王小白学习

QT学习笔记

Qt

“C:\Users\wang\Desktop\编程阅读书籍\my-books\C+±Qt5-范例开发大全.pdf”

文章目录

Qt

@[toc]

平时遇到的小问题

Vs 不能识别 Qt 组件问题

解决中文乱码问题：

窗体应用

QRect

固定窗体大小

设置窗体大小和背景颜色

修改标题栏图标

移动无边框窗体

去掉标题栏最大、最小化按钮

多窗体调用

字体形状窗体

控件应用

QPushButton 按钮

QLabel 标签

QLineEdit 单行文本

QTextEdit 多行文本

QPlainTextEdit 多行文本

QComboBox 下拉列表框

QFontComboBox 字体下拉列表框

QSpinBox 控件

QDateEdit 日期控件

QDateEdit 日期控件

QScrollBar 控件

QRadioButton 单选按钮

QCheckBox 复选框控件

QListView 列表控件

QTreeView 树控件

QTableView 表格控件

QHBoxLayout 横向布局

QGridLayout 网格布局

QGroupBox 分组框控件

QTabWidget 选项卡窗口控件

QMenu、QToolBar 菜单栏、工具栏控件

QSystemTrayIcon 任务栏托盘菜单

组件应用

日历组件

登录窗口

文件浏览对话框

颜色选择对话框

进度条实例

Timer实时更新时间

文件操作

创建文件夹

写入文件

修改文件内容:

删除文件

修改文件名

INI文件写入操作

INI文件读取操作

创建XML文件

读取XML文件

图形图像操作

绘制文字

绘制线条

绘制椭圆

显示静态图像

显示动态图像

图片水平移动

图片翻转

图片缩放

图片中加文字

图像扭曲

模糊效果

着色效果

阴影效果

透明效果

多媒体应用

音频、视频播放器

播放 Flash 动画

播放图片动画

操作系统

获取屏幕分辨率

获取本机名、IP地址

根据网址获取IP地址

判断键盘按下键值

获取系统环境变量

执行系统命令

注册表

写入注册表

查找注册表

修改 IE 浏览器的默认主页

数据库

查询数据库驱动

网络开发

TCP服务端

TCP客户端

线程与进程

线程管理器

线程 QThread 应用

线程 QRunnable 应用

平时遇到的小问题

qt操作 world 加 axcontainer 模块
判断相等
```
int A;
int B;
A.compare(B) == 0
```

字符串前的’R’字符

使字符串不被转义

const QString sql=R"(
                      CREATE TABLE IF NOT EXISTS  my_table (
                      id   INTEGER   PRIMARY KEY AUTOINCREMENT NOT NULL,
                      name CHAR (50) UNIQUE NOT NULL,
                      age  INTEGER
                      );)";

如：

“hello\nworld”

输出为

hello
world

R“hello\nworld”

输出为

hello\nworld

Vs 不能识别 Qt 组件问题

在项目属性页的vc++目录 -> 包含目录中增加 Qt 的 include 文件夹目录：

解决中文乱码问题：

在头文件加上：

#pragma execution_character_set("utf-8")

或者在每一中文前面加上：QStringLiteral()

button = new QPushButton(QStringLiteral("按钮A"), this);

mainwindows.h：

#pragma once
#pragma execution_character_set("utf-8")

#include 
#include  

#include "ui_MainWindow.h"

class MainWindow : public QMainWindow
{
	Q_OBJECT

public:
	MainWindow(QWidget *parent = Q_NULLPTR);

// 声明QPushButton
private:
	QPushButton *button;

	Ui::MainWindowClass ui;

// 声明QPushButton方法
private slots:
	void txtButton();
};

窗体应用

QRect

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include 

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 创建一个QLabel控件
    QLabel *label = new QLabel(this);
    // QLabel控件显示文字内容
    label->setText("Hekllo World");
    // 显示位置
    label->setGeometry(QRect(50,50,200,25));
}

MainWindow::~MainWindow()
{
    delete ui;
}

QRect(参数 1，参数 2，参数 3，参数 4)

参数 1：在窗体中 X 轴参数
参数 2：在窗体中 Y 轴参数
参数 3：QLabel 控件宽度
参数 4：QLabel 控件高度

    label->setGeometry(QRect(500,50,20,25));

固定窗体大小

设置最大、最小为同一值即可：

	// 窗体标题
    this->setWindowTitle("窗体应用");
    // 窗体最大 300*300
    this->setMaximumSize(300,300);
    // 窗体最小 300*300
    this->setMinimumSize(300,300);

设置窗体大小和背景颜色

	// 默认窗体居中显示，通过move或setGeometry更改
	// 设置X轴100，Y轴100
    this->move(100,100);
    // 背景红色
    this->setStyleSheet("background:red");

修改标题栏图标

	// 窗体标题
    this->setWindowTitle("窗体应用");
    // 窗体ICO图片，可以给图片取别名
    this->setWindowIcon(QIcon(":/images/qt.ico"));

移动无边框窗体

mainwindow.h:

...
    
#include 
#include 

...
    
class MainWindow : public QMainWindow
{
    
	...
    
// 定义鼠标三种状态方法
protected:
    // 鼠标按下
    void mousePressEvent(QMouseEvent *e);
    // 鼠标移动
    void mouseMoveEvent(QMouseEvent *e);
    // 鼠标释放
    void mouseReleaseEvent(QMouseEvent *e);

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

// 定义QPoint对象
private:
    QPushButton *btClose;
    QPoint last;

	...
    
};

...

mainwindow.cpp:

...

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ...

    // 标题名
    this->setWindowTitle("移动无边框窗体");
    // 去掉标题栏
    this->setWindowFlags(Qt::FramelessWindowHint);

    // 实例一个按钮控件，因为去掉标题栏，窗体就没有关闭按钮了。
    // 所以自己添加一个按钮实现关闭功能
    btClose = new QPushButton(this);
    btClose->setText("关闭");
    // 按钮点击事件
    connect(btClose,SIGNAL(clicked()),this,SLOT(close()));
        
    ...
}

// 获取鼠标点定位窗体的位置
void MainWindow::mousePressEvent(QMouseEvent *e){
    last = e->globalPos();
}

void MainWindow::mouseMoveEvent(QMouseEvent *e){
    int dx = e->globalX() - last.x();
    int dy = e->globalY() - last.y();

    last = e->globalPos();
    move(x()+dx, y()+dy);
}

void MainWindow::mouseReleaseEvent(QMouseEvent *e){
    int dx = e->globalX() - last.x();
    int dy = e->globalY() - last.y();

    move(x()+dx, y()+dy);
}

...

去掉标题栏最大、最小化按钮

	// 关闭按钮失效
    // this->setWindowFlags(Qt::FramelessWindowHint);
    // 去掉最大化、最小化按钮，保留关闭按钮
    this->setWindowFlags(Qt::WindowCloseButtonHint);

多窗体调用

选择 qt -> qt设计师界面类：

选择mainwindow，下一步：

修改类名为mainwindow2：

mainwindow.h:

...
    
#include  // 引入按钮类头文件
#include  // 引入mainwindow2类

...

class MainWindow : public QMainWindow
{
	...
        
private:
	...

    QPushButton *button;
    MainWindow2 w2;

    ...

// 实例方法
private slots:
    void showMainwindow2();
};
...

mainwindow.cpp:

	// 实例QPushButton控件
    button = new QPushButton(this);
    // 按钮显示位置
    button->setGeometry(QRect(50,50,100,25));
    // 按钮值
    button->setText("按钮");
    // 点击事件
    connect(button, SIGNAL(clicked()),this,SLOT(showMainwindow2()));

// 调用方法
void MainWindow::showMainwindow2(){
    // 显示MainWindow2窗体
    w2.show();
}

字体形状窗体

	// 去掉标题栏
    this->setWindowFlag(Qt::FramelessWindowHint);
    // 设置透明背景
    this->setAttribute(Qt::WA_TranslucentBackground, true);
    // 窗体添加样式，样式为css样式表
    // background-image:url 添加图片
    // background-repeat:no-repeat 不平铺
    this->setStyleSheet("background-image:url(:/images/op.png);background-repeat:no-repeat;");

控件应用

QPushButton 按钮

MainWindow.h:

#include

// 声明QPushButton
private:
	QPushButton *button;

// 声明QPushButton方法
private slots:
	void txtButton();

MainWindows.cpp:

	// 创建按钮
	//button = new QPushButton(QStringLiteral("按钮A"), this);
	button = new QPushButton("按钮A", this);
	// 定义按钮 X 轴，Y 轴，W 宽，H 高
	button->setGeometry(QRect(100, 100, 100, 25));
	// 给按钮添加槽事件（点击事件）
	connect(button, SIGNAL(released()), this, SLOT(txtButton()));

// 点击方法
void MainWindow::txtButton() 
{
	//  改变按钮文字
	button->setText("按钮B");
}

QLabel 标签

MainWindow.h：

#include

private:
	// 声明 QLabel
	QLabel *label;

MainWindow.cpp：

	// 实例 QLabel 控件
	label = new QLabel("我是QLabel", this);
	// QLabel 位置
	// label->move(100, 100);
	label->setGeometry(QRect(100, 100, 200, 300));
	// label 样式（css 样式）
	// font-size 字号
	// color 字体颜色
	// font-weight 自宽
	// font-style 字体样式
	label->setStyleSheet("font-size:20px; color:red; font-weight:bold; font-style:italic");

QLineEdit 单行文本

MainWindow.h：

#include

private:
	// 声明 QLineEdit 控件
	QLineEdit *lineEdit;

MainWindow.cpp：

	// 创建 QLineEdit 控件
	lineEdit = new QLineEdit(this);
	// 位置大小
	lineEdit->setGeometry(QRect(100, 100, 200, 25));
	// 样式
	// border 边框线大小
	// border-style 边框样式 solid 实线
	// border-color:blue red 上下蓝色 左右红色
	lineEdit->setStyleSheet("border:1px; border-style:solid; color:red; border-color:blue red;");
	// 限制最长输出12位
	lineEdit->setMaxLength(12);
	// 不可写入
	// lineEdit->setEchoMode(QLineEdit::NoEcho);
	// 密码*号输入
	lineEdit->setEchoMode(QLineEdit::Password);

QTextEdit 多行文本

MainWindow.h：

#include

private:
	// 声明	QTextEdit 控件
	QTextEdit *textEdit;

MainWindow.cpp：

	// 实例
	textEdit = new QTextEdit(this);
	// 位置
	textEdit->setGeometry(QRect(50, 50, 200, 100));
	// 添加内容
	textEdit->setText("我是第一行
我是第二行");

QPlainTextEdit 多行文本

MainWindow.h：

#include

private:
	// 声明 QPlainTextEdit 控件
	QPlainTextEdit *plainTextEdit;

MainWindow.cpp：

	// 实例
	plainTextEdit = new QPlainTextEdit(this);
	// 位置
	plainTextEdit->setGeometry(QRect(50, 50, 200, 150));
	// 添加内容
	plainTextEdit->setPlainText("我是第一行
我是第二行");

注：

QTextEdit 和 QPlainTextEdit 都为多行文本。但 QPlainTextEdit 可以理解为 QTextEdit 的低配版。QPlainTextEdit 支持纯文本显示，QTextEdit 支持富文本显示。就是多一个样式。
QPlainTextEdit 显示的效率比 QTextEdit 高，如果需要显示大量文字，尤其是需要滚动条来回滚动的时候，QPlainTextEdit 要好很多。

QComboBox 下拉列表框

MainWindow.h：

#include

private:	
	// 声明 QComboBox 控件
	QComboBox *comboBox;

MainWindow.cpp：

	// 实例 QComboBox
	comboBox = new QComboBox(this);
	// 控件显示位置大小
	comboBox->setGeometry(QRect(50, 50, 120, 25));
	// 定义字符串列表
	QStringList str;
	str << "数学" << "语文" << "地理";
	// 将字符串列表绑定 QComboBox 控件
	comboBox->addItems(str);

QFontComboBox 字体下拉列表框

MainWindow.h：

#include 
#include 
#include

private:	
	// 实例控件
	QFontComboBox *fontComboBox;
	QPushButton *button;
	QLabel *fontLabel;

MainWindow.cpp：

	// 实例 QFontComboBox
	fontComboBox = new QFontComboBox(this);
	// 实例 QPushButton
	button = new QPushButton(this);
	// 实例 QLabel
	fontLabel = new QLabel(this);
	fontLabel->setGeometry(QRect(50, 150, 300, 25));
	// 按钮名
	button->setText("按钮");
	// 位置
	button->move(180, 50);
	// 事件
	connect(button, SIGNAL(released()), this, SLOT(txtFontButton()));
	// QFontComboBox 控件位置
	fontComboBox->setGeometry(QRect(50, 50, 120, 25));

// 字体下拉方法
void MainWindow::txtFontButton()
{
	fontLabel->setText("选择字体:" + fontComboBox->currentText());
}

QSpinBox 控件

MainWindow.h:

#include

private:
	// 声明 QSpinBox 控件
	QSpinBox *spinBox;

MainWindow.cpp:

	// 实例 QSpinBox
	spinBox = new QSpinBox(this);
	// 位置
	spinBox->setGeometry(QRect(50, 50, 100, 25));
	// 值范围
	spinBox->setRange(0, 200);
	// 初始值
	spinBox->setValue(10);
	// 后缀
	spinBox->setSuffix("元");
	// 前缀
	spinBox->setPrefix("$");

QDateEdit 日期控件

MainWindow.h:

#include 
#include

private:
	// 声明 QTimeEdit 时间控件
	QTimeEdit *timeEdit;

MainWindow.cpp:

	// 实例 QTimeEdit
	timeEdit = new QTimeEdit(this);
	// 位置
	timeEdit->setGeometry(QRect(50, 50, 120, 25));
	// 获取系统时间
	QDateTime sysTime = QDateTime::currentDateTime();
	// 获取时分秒以 ':' 号拆分赋予list数组
	QStringList list = sysTime.toString("hh:mm:ss").split(':');
	// 将时分秒绑定控件 
	timeEdit->setTime(QTime(list[0].toInt(), list[1].toInt(), list[2].toInt()));

注：

Qt获取当前时间（超详细）_世纪隐龙的博客-CSDN博客_qt 时间

QDateEdit 日期控件

MainWindow.h:

#include 
#include

private:
	// 声明 QDateEdit 日期控件
	QDateEdit *dateEdit;

MainWindow.cpp:

	// 实例
	dateEdit = new QDateEdit(this);
	// 位置
	dateEdit->setGeometry(QRect(50, 50, 120, 25));
	// 获取系统时间
	QDateTime sysTime = QDateTime::currentDateTime();
	// 获取时间以 '-' 号拆分赋予 list 数组
	QStringList list = sysTime.toString("yyyy-MM-dd").split('-');
	// 将年月日绑定控件
	dateEdit->setDate(QDate(list[0].toInt(), list[1].toInt(), list[2].toInt()));

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QScrollBar 控件

MainWindow.h:

#include 
#include

private:
	// 实例控件
	QScrollBar *scrollBar;
	QSpinBox *spinBox;

MainWindow.cpp:

	// 实例
	scrollBar = new QScrollBar(this);
	spinBox = new QSpinBox(this);
	// 横显/竖显
	scrollBar->setOrientation(Qt::Horizontal);
	// 位置
	scrollBar->setGeometry(QRect(50, 50, 180, 20));
	spinBox->setGeometry(QRect(50, 90, 100, 25));
	// 控件条宽度
	scrollBar->setPageStep(10);
	// scrollBar 事件
	connect(scrollBar, SIGNAL(valueChanged(int)), spinBox, SLOT(setValue(int)));
	// 初始值
	scrollBar->setValue(50);

QRadioButton 单选按钮

MainWindow.h:

#include 
#include

private:
	// 实例控件
	QRadioButton *radioM;
	QRadioButton *radioW;
	QLabel *label;

private slots:
	// 单选按钮方法
	void radioChange();

MainWindow.cpp:

	// 实例
	radioM = new QRadioButton(this);
	radioW = new QRadioButton(this);
	label = new QLabel(this);
	// 位置
	radioM->setGeometry(QRect(50, 50, 50, 50));
	radioW->setGeometry(QRect(100, 50, 50, 50));
	label->setGeometry(QRect(50, 100, 100, 25));
	radioM->setText("男");
	radioW->setText("女");
	// 默认选择
	radioM->setChecked(true);
	label->setText("男");
	// 事件
	connect(radioM, SIGNAL(clicked()), this, SLOT(radioChange()));
	connect(radioW, SIGNAL(clicked()), this, SLOT(radioChange()));

// radio 点击方法
void MainWindow::radioChange()
{
	if (sender() == radioM)
	{
		label->setText("男");
	}
	else if (sender() == radioW)
	{
		label->setText("女");
	}
}

QCheckBox 复选框控件

MainWindow.h:

#include 
#include

private:
	// 实例复选框控件
	QCheckBox *checkBox01;
	QCheckBox *checkBox02;
	QCheckBox *checkBox03;
	QLabel *label;

private slots:
	// 复选框方法
	void checkChange();

MainWindow.cpp:

	//实例化 checkBox 控件
	checkBox01 = new QCheckBox(this);
	checkBox02 = new QCheckBox(this);
	checkBox03 = new QCheckBox(this);
	//实例 label 控件显示结果
	label = new QLabel(this);
	//控件位置
	checkBox01->setGeometry(QRect(50, 50, 50, 50));
	checkBox02->setGeometry(QRect(100, 50, 50, 50));
	checkBox03->setGeometry(QRect(150, 50, 50, 50));
	label->setGeometry(QRect(50, 100, 200, 30));
	//控件值
	checkBox01->setText("数学");
	checkBox02->setText("语文");
	checkBox03->setText("地理");
	//checkbox 控件点击事件
	connect(checkBox01, SIGNAL(clicked(bool)), this, SLOT(checkChange()));
	connect(checkBox02, SIGNAL(clicked(bool)), this, SLOT(checkChange()));
	connect(checkBox03, SIGNAL(clicked(bool)), this, SLOT(checkChange()));

// 定义接收变量
QString str;

void MainWindow::checkChange()
{
	if (sender() == checkBox01)
	{
		// 判断是否被选中
		if (checkBox01->checkState() == Qt::Checked)
		{
			str += "数学";
		}
		else
		{
			str = str.replace(QString("数学"), QString(""));
		}
	}
	else if (sender() == checkBox02)
	{
		if (checkBox02->checkState() == Qt::Checked)
		{
			str += "语文";
		}
		else
		{
			str = str.replace(QString("语文"), QString(""));
		}
	}
	else if (sender() == checkBox03)
	{
		if (checkBox03->checkState() == Qt::Checked)
		{
			str += "地理";
		}
		else
		{
			str = str.replace(QString("地理"), QString(""));
		}
	}
	// 绑定值
	label->setText(str);
}

QListView 列表控件

MainWindow.h:

#include  //QListView 类
#include  //数据模型类

private:
	// 实例列表控件
	QListView *listView;
	QStringListModel *model;

MainWindow.cpp:

	// 实例 listView 控件
	listView = new QListView(this);
	// 定义位置宽高
	listView->setGeometry(QRect(50, 50, 100, 100));
	// StringList 数组
	QStringList string;
	string << "数学" << "语文" << "外语" << "地理";
	// 添加数据
	model = new QStringListModel(string);
	// 将数据绑定 listView 控件
	listView->setModel(model);

QTreeView 树控件

MainWindow.h:

#include 
#include

private:
	// 实例树控件
	QTreeView *treeView;
	QStandardItemModel *model;

MainWindow.cpp:

	// 实例 QTreeView 控件
	treeView = new QTreeView(this);
	// 位置
	treeView->setGeometry(QRect(50, 50, 500, 500));
	// 实例数据类型 4 个节点，2 列
	model = new QStandardItemModel(3, 2);
	// 列名称
	model->setHeaderData(0, Qt::Horizontal, "第一列");
	model->setHeaderData(1, Qt::Horizontal, "第二列");
	// 定义节点
	QStandardItem *item1 = new QStandardItem("数学");
	item1->setIcon(QIcon(":/images/arm.png"));
	QStandardItem *item2 = new QStandardItem("语文");
	item2->setIcon(QIcon(":/images/arm.png"));
	QStandardItem *item3 = new QStandardItem("外语");
	item3->setIcon(QIcon(":/images/arm.png"));
	// 外语子项
	QStandardItem *item4 = new QStandardItem("外语 A");
	item4->setIcon(QIcon(":/images/arm.png"));
	item3->appendRow(item4);
	// 将节点添加至 QStandardItemModel
	model->setItem(0, 0, item1);
	model->setItem(1, 0, item2);
	model->setItem(2, 0, item3);
	// 将 QStandardItemModel 数据绑定 QTreeView 控件
	treeView->setModel(model);

QTableView 表格控件

MainWindow.h:

#include 
#include

private:
	// 实例表格控件
	QTableView *tableView;
	QStandardItemModel *model;

MainWindow.cpp:

	//实例
	tableView = new QTableView(this);
	//位置
	tableView->setGeometry(QRect(50, 50, 310, 200));
	//实例数据模型
	model = new QStandardItemModel();
	//定义列
	model->setHorizontalHeaderItem(0, new QStandardItem("数学"));
	model->setHorizontalHeaderItem(1, new QStandardItem("语文"));
	model->setHorizontalHeaderItem(2, new QStandardItem("外语"));
	//行数据 0 行,0 列
	model->setItem(0, 0, new QStandardItem("数学 A"));
	model->setItem(0, 1, new QStandardItem("语文 A"));
	model->setItem(0, 2, new QStandardItem("外语 A"));
	model->setItem(1, 0, new QStandardItem("数学 B"));
	model->setItem(1, 1, new QStandardItem("语文 B"));
	model->setItem(1, 2, new QStandardItem("外语 B"));
	//将数据模型绑定控件
	tableView->setModel(model);

QHBoxLayout 横向布局

MainWindow.h:

#include 
#include 
#include

private:
	// 定义横向布局控件
	QHBoxLayout *hboxLayout;
	QPushButton *button1;
	QPushButton *button2;
	QPushButton *button3;
	QWidget *widget;

MainWindow.cpp:

	// 创建横向布局
	hboxLayout = new QHBoxLayout();
	button1 = new QPushButton("按钮 1");
	button2 = new QPushButton("按钮 2");
	button3 = new QPushButton("按钮 3");
	// 向布局中添加控件
	hboxLayout->addWidget(button1);
	hboxLayout->addWidget(button2);
	hboxLayout->addWidget(button3);
	// 间隔
	hboxLayout->setSpacing(60);
	// 实例 QWidget
	widget = new QWidget();
	// 绑定布局
	widget->setLayout(hboxLayout);
	// 绑定界面
	this->setCentralWidget(widget);

QGridLayout 网格布局

MainWindow.h:

#include 
#include 
#include

private:
	// 定义网格布局控件
	QGridLayout *gridLayout;
	QPushButton *button1;
	QPushButton *button2;
	QPushButton *button3;
	QWidget *widget;

MainWindow.cpp:

	// 创建纵向布局
	gridLayout = new QGridLayout();
	button1 = new QPushButton("按钮 1");
	button2 = new QPushButton("按钮 2");
	button3 = new QPushButton("按钮 3");
	// 向布局中添加控件
	gridLayout->addWidget(button1, 0, 0, 1, 1);
	gridLayout->addWidget(button2, 0, 1, 1, 1);
	gridLayout->addWidget(button3, 1, 0, 1, 1);
	// 实例 QWidget
	widget = new QWidget();
	// 绑定布局
	widget->setLayout(gridLayout);
	// 绑定界面
	this->setCentralWidget(widget);

QGroupBox 分组框控件

MainWindow.h:

#include 
#include 
#include

private:
	// 实例控件
	QGroupBox *box;
	QPushButton *button;
	QVBoxLayout *vbox;

MainWindow.cpp:

	// 实例 QGroupBox
	box = new QGroupBox(this);
	// 位置、大小
	box->setGeometry(QRect(30, 30, 340, 100));
	// 标题
	box->setTitle("语音栏目");
	// 实例按钮
	button = new QPushButton();
	button->setText("按钮");
	// 实例布局
	vbox = new QVBoxLayout;
	// 将按钮加入布局
	vbox->addWidget(button);
	// 将布局加入 QGroupBox 控件
	box->setLayout(vbox);

QTabWidget 选项卡窗口控件

MainWindow.h:

#include 
#include 
#include

private:
	// 实例 QTabWidget 控件
	QTabWidget *tabWidget;

//tabA 类
class tabA :public QWidget
{
	Q_OBJECT
public:
	tabA(QWidget *parent = 0);
};

//tabB 类
class tabB :public QWidget
{
	Q_OBJECT
public:
	tabB(QWidget *parent = 0);
};

MainWindow.cpp:

	//实例 QTabWidget
	tabWidget = new QTabWidget(this);
	tabWidget->setGeometry(QRect(30, 30, 340, 140));
	tabWidget->addTab(new tabA, "A 栏目");
	tabWidget->addTab(new tabB, "B 栏目");

tabA::tabA(QWidget *parent) :QWidget(parent)
{
	QPushButton *buttonA = new QPushButton(this);
	buttonA->setText("页面 A");
}

tabB::tabB(QWidget *parent) :QWidget(parent)
{
	QPushButton *buttonB = new QPushButton(this);
	buttonB->setText("页面 B");
}

QMenu、QToolBar 菜单栏、工具栏控件

MainWindow.h:

#include 
#include 
#include 
#include 
#include

private:
	// 实例 QMenu QToolBar 控件
	QMenu *fileMenu, *editMenu, *helpMenu;
	QToolBar *fileToolBar, *editToolBar;
	QAction *newAct;
	QAction *cutAct;
	QAction *copyAct;
	QAction *pasteAct;
	QAction *aboutQtAct;

private slots:
	// 声明创建方法	
	void newFile();

MainWindow.cpp:

	// 实例菜单
	fileMenu = new QMenu(this);
	editMenu = new QMenu(this);
	helpMenu = new QMenu(this);
	// 填充菜单子节点
	newAct = new QAction(QIcon(":/images/new"), tr("新建"), this);
	newAct->setShortcut(tr("Ctrl+N"));
	newAct->setStatusTip(tr("新建文件"));
	connect(newAct, SIGNAL(triggered()), this, SLOT(newFile()));
	cutAct = new QAction(QIcon(":/images/cut"), tr("剪切"), this);
	cutAct->setShortcut(tr("Ctrl+X"));
	cutAct->setStatusTip(tr("剪切内容"));
	copyAct = new QAction(QIcon(":/images/copy"), tr("复制"), this);
	copyAct->setShortcut(tr("Ctrl+C"));
	copyAct->setStatusTip(tr("复制内容"));
	pasteAct = new QAction(QIcon(":/images/paste"), tr("粘贴"), this);
	pasteAct->setShortcut(tr("Ctrl+V"));
	pasteAct->setStatusTip(tr("粘贴内容"));
	aboutQtAct = new QAction(tr("关于 Qt"), this);
	aboutQtAct->setStatusTip(tr("关于 Qt 信息"));
	connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
	// 填充菜单
	fileMenu = menuBar()->addMenu(tr("文件"));
	fileMenu->addAction(newAct);
	fileMenu->addSeparator(); // 分割线
	editMenu = menuBar()->addMenu(tr("编辑"));
	editMenu->addAction(cutAct);
	editMenu->addAction(copyAct);
	editMenu->addAction(pasteAct);
	menuBar()->addSeparator();
	helpMenu = menuBar()->addMenu(tr("帮助"));
	helpMenu->addAction(aboutQtAct);
	// toolBar 工具条
	fileToolBar = addToolBar(tr("新建"));
	fileToolBar->addAction(newAct);
	editToolBar = addToolBar(tr("修改"));
	editToolBar->addAction(cutAct);
	editToolBar->addAction(copyAct);
	editToolBar->addAction(pasteAct);

// 子菜单事件
void MainWindow::newFile() {
	QMessageBox::warning(this, tr("Warning"), tr("创建新文件？"), QMessageBox::Yes | QMessageBox::Default, QMessageBox::No);
}

QSystemTrayIcon 任务栏托盘菜单

MainWindow.h:

#include //任务栏类
#include //菜单类

private:
	// 实例任务栏菜单控件
	QSystemTrayIcon *myTrayIcon;
	QMenu *myMenu;
	QAction *restoreWinAction;
	QAction *quitAction;
	void createMenu();

private slots:
	// 声明恢复方法
	void showNormal();

MainWindow.cpp:

	// 菜单
	createMenu();
	// 判断系统是否支持托盘图标
	if (!QSystemTrayIcon::isSystemTrayAvailable())
	{
		return;
	}
	// 实例 QSystemTrayIcon
	myTrayIcon = new QSystemTrayIcon(this);
	// 设置图标
	myTrayIcon->setIcon(QIcon(":/images/bitbug_favicon.ico"));
	// 鼠标放托盘图标上提示信息
	myTrayIcon->setToolTip("Qt 托盘图标功能");
	// 设置消息
	myTrayIcon->showMessage("托盘", "托盘管理", QSystemTrayIcon::Information, 10000);
	// 托盘菜单
	myTrayIcon->setContextMenu(myMenu);
	// 显示
	myTrayIcon->show();

// 绘制菜单
void MainWindow::createMenu()
{
	restoreWinAction = new QAction("恢复(&R)", this);
	quitAction = new QAction("退出(&Q)", this);
	// 恢复
	connect(restoreWinAction, SIGNAL(triggered()), this, SLOT(showNormal()));
	// 退出
	connect(quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
	myMenu = new QMenu((QWidget*)QApplication::desktop());
	// 添加菜单
	myMenu->addAction(restoreWinAction);
	// 分隔符
	myMenu->addSeparator();
	myMenu->addAction(quitAction);
}

// 恢复
void MainWindow::showNormal()
{
	this->show();
}

// 点击最小化按钮隐藏界面
void QWidget::changeEvent(QEvent *e)
{
	if ((e->type() == QEvent::WindowStateChange) && this->isMinimized())
	{
		//QTimer::singleShot(100, this, SLOT(hide()));
		this->hide();
	}
}

组件应用

日历组件

mainwindow.h:

#pragma once
#pragma execution_character_set("utf-8")

#include 
#include 
#include 
#include 

#include "ui_MainWindow.h"

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = Q_NULLPTR);

private:
    Ui::MainWindowClass ui;

	QLabel *label;
	QLineEdit *lineEdit;
	QCalendarWidget *calendarWidget;

private slots:
	void showTime();
	void setData();
};

mainwindow.cpp:

#include "MainWindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

	// 实例QLabel控件
	label = new QLabel(this);
	label->setText("选择日期:");
	// 位置
	label->setGeometry(QRect(50, 50, 100, 25));
	lineEdit = new QLineEdit(this);
	lineEdit->setGeometry(QRect(150, 50, 150, 22));
	// 事件
	connect(lineEdit, SIGNAL(cursorPositionChanged(int, int)), this, SLOT(showTime()));
	// 实例事件控件
	calendarWidget = new QCalendarWidget(this);
	// 位置
	calendarWidget->setGeometry(20, 75, 350, 180);
	// 隐藏时间控件
	calendarWidget->setHidden(true);
	// 时间控件点击事件
	connect(calendarWidget, SIGNAL(clicked(QDate)), this, SLOT(setData()));

}

void MainWindow::showTime()
{
	calendarWidget->setHidden(false);
}

void MainWindow::setData()
{
	// 选择接受时间
	QDate data = calendarWidget->selectedDate();
	// 时间格式化
	QString str = data.toString("yyyy-MM-dd");
	// 赋值
	lineEdit->setText(str);
	// 日期控件隐藏
	calendarWidget->setHidden(true);
}

登录窗口

Widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include 

#include 
#include  // 纵向布局
#include 
#include  // 按钮
#include  // 横向布局
#include  // 垂直布局
#include  // 消息对话框

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();

private:
    QLineEdit *usrLineEdit;
    QLineEdit *pwdLineEdit;
    QLabel *usrLabel;
    QLabel *pwdLabel;
    QGridLayout *gridLayout;
    QPushButton *okButton;
    QPushButton *canceButton;
    QVBoxLayout *vboxLayout;

public slots:
    virtual void accept();

};
#endif // WIDGET_H

Widget.cpp:

#include "widget.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    // 窗体最小宽度高度
        setMinimumSize(280, 150);
        // 窗体最大高度宽度
        setMaximumSize(280, 150);

        // 实例用户名 密码
        usrLabel = new QLabel(tr("用户名:"));
        pwdLabel = new QLabel(tr("密  码:"));
        usrLineEdit = new QLineEdit;
        pwdLineEdit = new QLineEdit;
        // 密码*号输入
        pwdLineEdit->setEchoMode(QLineEdit::Password);
        // 限制输入12位
        usrLineEdit->setMaxLength(12);
        pwdLineEdit->setMaxLength(12);

        // 实例网格布局控件
        gridLayout = new QGridLayout;

        // 添加布局 0，0，1，1 行 列 行间距 列间距
        gridLayout->addWidget(usrLabel, 0, 0, 1, 1);
        gridLayout->addWidget(usrLineEdit, 0, 1, 1, 1);

        // 间隔
        gridLayout->setSpacing(20);

        gridLayout->addWidget(pwdLabel, 1, 0, 1, 1);
        gridLayout->addWidget(pwdLineEdit, 1, 1, 1, 1);

        // 实例按钮控件
        okButton = new QPushButton(tr("确定"));
        canceButton = new QPushButton(tr("取消"));

        connect(okButton, SIGNAL(clicked()), this, SLOT(accept()));
        connect(canceButton, SIGNAL(clicked()), this, SLOT(reject()));

        QHBoxLayout *hboxLayout = new QHBoxLayout;

        hboxLayout->setSpacing(60);

        // 横向布局填充控件
        hboxLayout->addWidget(okButton);
        hboxLayout->addWidget(canceButton);

        // 实例纵向布局填充刚刚实例的两个布局
        vboxLayout = new QVBoxLayout;
        vboxLayout->addLayout(gridLayout);
        vboxLayout->addLayout(hboxLayout);

        // 显示内容
        this->setLayout(vboxLayout);
}

// 确定方法
void Widget::accept()
{
    // trimmed 去空字符
    if(usrLineEdit->text().trimmed() == "admin" && pwdLineEdit->text().trimmed() == "admin")
    {
        Widget::accept();
    }
    else
    {
        QMessageBox::warning(this,"警告","用户名或密码错误!!!", QMessageBox::Yes);
        usrLineEdit->setFocus();
    }
}


Widget::~Widget()
{
}

文件浏览对话框

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include  // 单行文本控制类
#include  // 按钮类
#include  // 引用文件浏览对话框

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QLineEdit *filename;
    QPushButton *button;

private slots:
    void showFiles();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 实例单行文本控件
    filename = new QLineEdit(this);
    // 位置
    filename->setGeometry(QRect(50,50,230,25));
    // 实例按钮
    button = new QPushButton(this);
    // 按钮位置
    button->setGeometry(QRect(280,50,80,25));
    // 按钮名
    button->setText("浏览");
    // 按钮点击事件
    connect(button,SIGNAL(clicked()),this,SLOT(showFiles()));
}

// 按钮点击方法
void MainWindow::showFiles()
{
    // 定义变量str接受QFileDialog对话框获取文件路径
    QString str = QFileDialog::getOpenFileName(this,"open file","/","text file(*.txt);;C file(*.cpp);;All file(*.*)");
    // 将变量绑定QLineEdit控件
    filename->setText(str.toUtf8());
}

MainWindow::~MainWindow()
{
    delete ui;
}

颜色选择对话框

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QPushButton *button;
    QLabel *label;

private slots:
    void editText();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 实例按钮
    button = new QPushButton(this);
    // 位置
    button->setGeometry(QRect(200,50,80,25));
    // 按钮值
    button->setText("选择颜色");
    // 按钮事件
    connect(button,SIGNAL(clicked()),this,SLOT(editText()));
    // 实例QLabel
    label = new QLabel(this);
    // label 位置
    label->setGeometry(QRect(50,50,200,25));
    // label 值
    label->setText("我的颜色可以改变");
}

MainWindow::~MainWindow()
{
    delete ui;
}

// 修改方法
void MainWindow::editText()
{
    // 颜色对话框设置
    QColorDialog::setCustomColor(0,QRgb(0xCCFFFF));
    // 定义QColor接受值
    QColor color = QColorDialog::getColor(QColor(0,250,0));
    // 定义Qpalette(调色板类)
    QPalette p = palette();
    // 调色板接受颜色
    p.setColor(QPalette::WindowText,QColor(color));
    // 给label绑定颜色
    label->setPalette(p);
}

进度条实例

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include  // 按钮类
#include  // 进度条类

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QPushButton *button;
    QProgressBar *bar;

private slots:
    void startBar();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 实例 QProgressBar 控件
    bar = new QProgressBar(this);
    // 位置
    bar->setGeometry(QRect(50,50,200,20));
    // 范围值
    bar->setRange(0,100000-1);
    // 初始值
    bar->setValue(0);
    // 实例button
    button = new QPushButton(this);
    // 位置
    button->setGeometry(QRect(270,50,80,25));
    // 值
    button->setText("开始");
    // 事件
    connect(button,SIGNAL(clicked()),this,SLOT(startBar()));
}

void MainWindow::startBar()
{
    for(int i = 0; i < 100000; ++i)
    {
        // 100% 结束
        if(i == 99999)
        {
            button->setText("结束");
        }

        // 赋值
        bar->setValue(i);
    }
}

MainWindow::~MainWindow()
{
    delete ui;
}

Timer实时更新时间

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QLabel *label;
    QTimer *timer;

private slots:
    void timerTime();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 实例 QLabel控件
    label = new QLabel(this);
    // 位置
    label->setGeometry(QRect(50,50,250,25));
    // 实例 QTimer 控件
    timer = new QTimer;
    // timer时间
    connect(timer,SIGNAL(timeout()),this,SLOT(timerTime()));
    // 执行
    timer->start(1000);
}

void MainWindow::timerTime()
{
    // 获取系统时间
    QDateTime sysTime = QDateTime::currentDateTime();
    label->setText(sysTime.toString());
}

MainWindow::~MainWindow()
{
    delete ui;
}

文件操作

创建文件夹

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QLineEdit *edit; // 写文件路径
    QPushButton *button; // 创建路径文件按钮

private slots:
    void createFolder(); // 创建文件
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include 
#include 

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 实例QLineEdit控件
    edit = new QLineEdit(this);
    // 位置
    edit->setGeometry(QRect(50,50,250,25));
    // 值
    edit->setText("D://CreateQtLearnFolder");
    // 实例按钮
    button = new QPushButton(this);
    // 按钮位置、大小
    button->setGeometry(QRect(280,50,80,25));
    // 值
    button->setText("创建");
    // 按钮事件
    connect(button,SIGNAL(clicked()),this,SLOT(createFolder()));

}

void MainWindow::createFolder()
{
    // 实例QDir
    QDir *folder = new QDir;
    // 判断创建文件夹是否存在
    bool exist = folder->exists(edit->text());
    if(exist)
    {
        QMessageBox::warning(this,tr("创建文件夹"),tr("文件夹已存在！"));
    } else
    {
        // 创建文件夹
        bool ok = folder->mkdir(edit->text());
        // 判断是否创建成功
        if(ok)
        {
            QMessageBox::warning(this,tr("创建文件夹"),tr("文件夹创建成功！"));
        } else
        {
            QMessageBox::warning(this,tr("创建文件夹"),tr("文件夹创建失败！"));
        }

    }
}

MainWindow::~MainWindow()
{
    delete ui;
}

写入文件

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QPushButton *button;
    QLineEdit *edit;
    QLineEdit *content;


private slots:
    void createFile(); // 创建文件
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include 
#include 

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 实例
    edit = new QLineEdit(this);
    // 位置
    edit->setGeometry(QRect(50,50,200,25));
    // 值
    edit->setText("D:/Qt02.txt");
    // 实例
    content = new QLineEdit(this);
    // 位置
    content->setGeometry(QRect(50,100,200,25));
    // 值
    content->setText("写入文件内容");

    // 实例button
    button = new QPushButton(this);
    // 位置
    button->setGeometry(QRect(270,50,80,25));
    // 值
    button->setText("创建");
    // 事件
    connect(button,SIGNAL(clicked()),this,SLOT(createFile()));
}

MainWindow::~MainWindow()
{
    delete ui;
}

// 创建文件
void MainWindow::createFile()
{
    // 实例 QFile
    QFile file(edit->text());
    // 判断文件是否存在
    if(file.exists())
    {
        QMessageBox::warning(this,"创建文件","文件已经存在！");
    }
    else
    {
        // 存在打开，不存在创建
        file.open(QIODevice::ReadWrite | QIODevice::Text);
        // 写入内容，这里需要转码，否则报错
        QByteArray str = content->text().toUtf8();
        // 写入 QByteArray 格式字符串
        file.write(str);
        // 提示成功
        QMessageBox::warning(this,"创建文件","文件创建成功！");
    }
    // 关闭文件
    file.close();
}

修改文件内容:

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QPushButton *browseBt;
    QPushButton *saveBt;
    QTextEdit *edit;
    QTextEdit *content;

private slots:
    // 保存文件
    void saveFile();
    // 浏览文件
    void browseFile();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include 
#include 
#include 
#include 

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 文件路径
    edit = new QTextEdit(this);
    edit->setGeometry(QRect(50,50,240,26));

    // 浏览文件按钮
    browseBt = new QPushButton(this);
    browseBt->setGeometry(QRect(290,50,80,25));
    browseBt->setText("浏览文件");
    connect(browseBt,SIGNAL(clicked()),this,SLOT(browseFile()));

    // 显示文件内容
    content = new QTextEdit(this);
    content->setGeometry(QRect(50,80,320,150));

    // 修改完毕，保存文件

    saveBt = new QPushButton(this);
    saveBt->setGeometry(QRect(290,240,80,25));
    saveBt->setText("保存");
    connect(saveBt,SIGNAL(clicked()),this,SLOT(saveFile()));
}

MainWindow::~MainWindow()
{
    delete ui;
}

// 保存文件
void MainWindow::saveFile()
{
    QFile file(edit->toPlainText());
    file.open(QIODevice::ReadWrite | QIODevice::Text);
    //  写入内容，这里需要转码，否则报错
    QByteArray str = content->toPlainText().toUtf8();
    // 写入QByteArray格式字符串
    file.write(str);
    // 提示成功
    QMessageBox::warning(this,"修改文件","修改文件成功!");
    file.close();
}

// 浏览文件
void MainWindow::browseFile()
{
    // 定义 str 接收 QFileDialog 对话框获取的文件路径
    QString str = QFileDialog::getOpenFileName(this,"open file","/","text file(*.txt);;C file(*.cpp);;All file(*.*)");
    // 将变量绑定QTextEdit控件
    edit->setText(str.toUtf8());
    // 判断是否选择文件
    if(edit->toPlainText().isEmpty())
    {
        return;
    }
    QFile file(edit->toPlainText());
    // 判断文件是否成功打开
    if(!file.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        QMessageBox::warning(this,"打开文件","打开文件失败!");
        return;
    }
    QTextStream ts(&file);
    // 循环文档数据至结尾
    while (!ts.atEnd())
    {
        // 将全部数据绑定至content控件
         content->setPlainText(ts.readAll());
    }

    // 关闭文档
    file.close();
}

删除文件

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QLineEdit *filePath;
    QPushButton *browseBt;
    QPushButton *deleteBt;

private slots:
    // 浏览文件
    void browseFile();
    // 删除文件
    void deleteFile();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include 

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 显示文件路径
    filePath = new QLineEdit(this);
    filePath->setGeometry(QRect(50,50,200,25));

    // 浏览文件按钮
    browseBt = new QPushButton(this);
    browseBt->setText("浏览文件");
    browseBt->setGeometry(QRect(270,50,80,25));
    connect(browseBt,SIGNAL(clicked()),this,SLOT(browseFile()));

    // 删除文件按钮
    deleteBt = new QPushButton(this);
    deleteBt->setText("删除文件");
    deleteBt->setGeometry(QRect(50,100,80,25));
    connect(deleteBt,SIGNAL(clicked()),this,SLOT(deleteFile()));
}

MainWindow::~MainWindow()
{
    delete ui;
}

// 浏览文件
void MainWindow::browseFile()
{
    // 定义变量str接收QFileDialog对话框获取的文件路径
    QString str = QFileDialog::getOpenFileName(this,"open file","/","text file(*.txt);;C file(*.cpp);;All file(*.*)");
    // 将变量绑定QTextEdit控件
    filePath->setText(str.toUtf8());
}

// 删除文件
void MainWindow::deleteFile()
{
    // 删除文件
    QFile::remove(filePath->text());
}

修改文件名

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QLineEdit *filePath;
    QLineEdit *newName;
    QPushButton *browseBt;
    QPushButton *saveBt;

private slots:
    // 浏览文件
    void browseFile();
    // 删除文件
    void saveFile();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include 
#include 

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 文件路径
    filePath = new QLineEdit(this);
    filePath->setGeometry(50,50,200,25);

    // 浏览按钮
    browseBt = new QPushButton(this);
    browseBt->setGeometry(QRect(270,50,80,25));
    browseBt->setText("浏览");
    connect(browseBt,SIGNAL(clicked()),this,SLOT(browseFile()));

    // 新名字
    newName = new QLineEdit(this);
    newName->setGeometry(QRect(50,90,200,25));
    newName->setText("新名字.txt");

    // 保存按钮
    saveBt = new QPushButton(this);
    saveBt->setGeometry(QRect(270,90,80,25));
    saveBt->setText("保存");
    connect(saveBt,SIGNAL(clicked()),this,SLOT(saveFile()));
}

MainWindow::~MainWindow()
{
    delete ui;
}

// 浏览
void MainWindow::browseFile()
{
    // 定义变量str接受QFileDialog对话框获取的文件路径
    QString str = QFileDialog::getOpenFileName(this,"open file","/","text file(*.txt);;C file(*.cpp);;All file(*.*)");
    // 将变量绑定QTextEdit控件
    filePath->setText(str.toUtf8());
}

// 保存
void MainWindow::saveFile()
{
    // 实例QFileInfo函数
    QFileInfo file(filePath->text());
    // 获取文件路径
    QString path = file.absolutePath();
    // bool型变量接受是否修改成功，成功为true，不成功为false
    bool x = QFile::rename(filePath->text(), path + "/" + newName->text());
    if(x)
    {
        QMessageBox::warning(this,"修改文件名","文件修改成功!");
    } else
    {
        QMessageBox::warning(this,"修改文件名","文件修改失败!");
    }
}

INI文件写入操作

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 
#include 
#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QGridLayout *gLayout;
    QWidget *widget;
    QLabel *filePathL; // ini 文件路径Label
    QLineEdit *filePath; // ini 文件路径输入框
    QLabel *nodeL; // 节点Label
    QLineEdit *nodeEdit; // 节点输入框
    QLabel *keyL; // 键Label
    QLineEdit *keyEdit; // 键输入框
    QLabel *valL; // 值Label
    QLineEdit *valEdit;// 值输入框
    QPushButton *writeBt; // 按钮
    QSettings *writeIni;

private slots:
    void writeFile();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // ini 文件路径Label
    filePathL = new QLabel;
    filePathL->setText("ini 文件完整路径");

    // ini 文件路径输入框
    filePath = new QLineEdit;
    filePath->setText("D:/a001.ini");

    // 节点Label
    nodeL = new QLabel;
    nodeL->setText("节点名");

    // 节点输入框
    nodeEdit = new QLineEdit;
    nodeEdit->setText("node");

    // 键Label
    keyL = new QLabel;
    keyL->setText("键值");

    // 键输入框
    keyEdit = new QLineEdit;
    keyEdit->setText("ip");

    // 值Label
    valL = new QLabel;
    valL->setText("值");

    // 值输入框
    valEdit = new QLineEdit;
    valEdit->setText("192.168.1.1");

    // 按钮
    writeBt = new QPushButton;
    writeBt->setText("写入文件");
    connect(writeBt,SIGNAL(clicked()),this,SLOT(writeFile()));

    gLayout = new QGridLayout;
    gLayout->addWidget(filePathL,0,0,1,1);
    gLayout->addWidget(filePath,0,1,1,4);
    gLayout->addWidget(nodeL,1,0,1,1);
    gLayout->addWidget(nodeEdit,1,1,1,1);
    gLayout->addWidget(keyL,2,0,1,1);
    gLayout->addWidget(keyEdit,2,1,1,1);
    gLayout->addWidget(valL,2,3,1,1);
    gLayout->addWidget(valEdit,2,4,1,1);
    gLayout->addWidget(writeBt,3,4,1,1);

    // 实例QWidget
    widget = new QWidget();
    // 绑定布局
    widget->setLayout(gLayout);
    this->setCentralWidget(widget);
}

MainWindow::~MainWindow()
{
    delete ui;
}

// 写入文件
void MainWindow::writeFile()
{
    // QSettings 构造函数的第一个参数是ini文件的路径，第二个参数表示针对ini文件
    writeIni = new QSettings(filePath->text(),QSettings::IniFormat);
    // 写入键、值
    writeIni->setValue(nodeEdit->text() + "/" + keyEdit->text(), valEdit->text());
    // 写入完成删除指针
    delete writeIni;
}

INI文件读取操作

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 
#include 
#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QGridLayout *gLayout;
    QWidget *widget;
    QLabel *filePathL;// ini 文件路径Label
    QLineEdit *filePath;// ini 文件路径输入框
    QLabel *nodeL;// 节点Label
    QLineEdit *nodeEdit;// 节点输入框
    QLabel *keyL;// 键Label
    QLineEdit *keyEdit;// 键输入框
    QLabel *valL;// 值Label
    QLineEdit *valEdit;// 值输入框
    QPushButton *readBt;// 按钮
    QSettings *readIni;

private slots:
    void readFile();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // ini 文件路径Label
    filePathL = new QLabel;
    filePathL->setText("ini 文件完整路径");

    // ini 文件路径输入框
    filePath = new QLineEdit;
    filePath->setText("D:/a001.ini");

    // 节点Label
    nodeL = new QLabel;
    nodeL->setText("节点名");

    // 节点输入框
    nodeEdit = new QLineEdit;
    nodeEdit->setText("node");

    // 键Label
    keyL = new QLabel;
    keyL ->setText("键值");

    // 键输入框
    keyEdit = new QLineEdit;
    keyEdit->setText("ip");

    // 值Label
    valL = new QLabel;
    valL->setText("值");

    // 值输入框
    valEdit = new QLineEdit;

    // 按钮
    readBt = new QPushButton;
    readBt->setText("读取文件");
    connect(readBt,SIGNAL(clicked()),this,SLOT(readFile()));

    gLayout = new QGridLayout;
    gLayout->addWidget(filePathL,0,0,1,1);
    gLayout->addWidget(filePath,0,1,1,4);
    gLayout->addWidget(nodeL,1,0,1,1);
    gLayout->addWidget(nodeEdit,1,1,1,1);
    gLayout->addWidget(keyL,2,0,1,1);
    gLayout->addWidget(keyEdit,2,1,1,1);
    gLayout->addWidget(valL,2,3,1,1);
    gLayout->addWidget(valEdit,2,4,1,1);
    gLayout->addWidget(readBt,3,4,1,1);

    // 实例QWidget
    widget = new QWidget();
    // 绑定布局
    widget->setLayout(gLayout);
    this->setCentralWidget(widget);
}

MainWindow::~MainWindow()
{
    delete ui;
}

// 读取文件
void MainWindow::readFile()
{
    // QSettings构造函数的第一个参数是ini文件的路径，第二个参数表示针对ini文件
    readIni = new QSettings(filePath->text(),QSettings::IniFormat);
    // 将读取到的ini文件保存在QString中，先取值，然后通过toString（）函数换成QString类型
    QString STR = nodeEdit->text() + "/" + keyEdit->text();
    QString ipResult = readIni->value(STR).toString();
    // 将结果绑定IP值控件上
    valEdit->setText(ipResult);
    // 写入完成删除指针
    delete readIni;
}

创建XML文件

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QLabel *explainL;
    QPushButton *createBt;

private slots:
    void createFile();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include 
#include 

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 实例QLabel
    explainL = new QLabel(this);
    explainL->setText("这里就不重复写类似txt读写布局了，直接在代码中\r\n填写节点等操作。\r\n文件路径：D:/a001.xml\r\n根节点：Root");
    explainL->setGeometry(QRect(50,50,300,100));

    // 实例按钮
    createBt = new QPushButton(this);
    createBt->setText("创建XML文件");
    createBt->setGeometry(QRect(50,180,100,25));
    connect(createBt,SIGNAL(clicked()),this,SLOT(createFile()));
}

MainWindow::~MainWindow()
{
    delete ui;
}

// 创建文件
void MainWindow::createFile()
{
    // 文件路径
    QString xmlPath = "D:/a001.xml";
    QFile file(xmlPath);
    if(file.open(QIODevice::WriteOnly|QIODevice::Text))
    {
        // 实例QXmlStreamWriter
        QXmlStreamWriter stream(&file);
        stream.setAutoFormatting(true);
        // 文档头
        stream.writeStartDocument();
        // 根节点
        stream.writeStartElement("Root");
        // 元素、值
        stream.writeAttribute("href","http://qt.nokia.com/");
        // 节点内容
        stream.writeTextElement("title","Qt Home");
        stream.writeEndElement();
        stream.writeEndDocument();
        // 关闭文件
        file.close();
    }
}

读取XML文件

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

    QLabel *resultL;
    QPushButton *readBt;

private slots:
    void readNode();
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include 
#include 

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 实例QLabel
    resultL = new QLabel(this);
    resultL->setGeometry(QRect(50,50,300,100));

    // 实例按钮
    readBt = new QPushButton(this);
    readBt->setText("读取title节点");
    readBt->setGeometry(QRect(50,180,150,25));
    connect(readBt,SIGNAL(clicked()),this,SLOT(readNode()));
}

MainWindow::~MainWindow()
{
    delete ui;
}

// 读取节点
void MainWindow::readNode()
{
    // 文件路径
    QString xmlPath = "D:/a001.xml";
    QFile file(xmlPath);

    // 定义变量接受信息
    QString str;
    // 判断文件是否存在
    if(file.exists())
    {
        if(file.open(QIODevice::ReadOnly|QIODevice::Text))
        {
            // 实例QXmlStreamReader对象读取文件
            QXmlStreamReader xmlRead(&file);

            // 循环节点
            while (!xmlRead.atEnd()) {
                // 指针下移
                xmlRead.readNext();
                if(xmlRead.isStartElement())
                {
                    // 如果节点有等于title的
                    if(xmlRead.name() == "title")
                    {
                        // 取title值赋予变量str
                        str = xmlRead.readElementText();
                    } else {
                        str = "没有找到节点";
                    }
                }
            }
            // 将值绑定QLabel控件显示
            resultL->setText(str);
        } else {
            resultL->setText("文件打开失败");
        }
        // 关闭文件
        file.close();
    }else {
        resultL->setText("文件不存在");
    }
}

图形图像操作

绘制文字

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include 
#include 

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    // 实例QGraphicsScene
    QGraphicsScene *scene = new QGraphicsScene;
    // 背景色
    scene->setForegroundBrush(QColor(0,255,255,127));
    // 字体设置
    QFont font("黑体",60);
    // 添加文字
    scene->addSimpleText("图形图像",font);
    // 网格
    // scene->setForegroundBrush(QBrush(Qt::lightGray,Qt::CrossPattern));
    // 实例QGraphicsView
    QGraphicsView *view = new QGraphicsView(scene);
    // 显示
    this->setCentralWidget(view);
}

MainWindow::~MainWindow()
{
    delete ui;
}

绘制线条

qtLearn5PaintLine.cpp:

#include "qtLearn5PaintLine.h"

#include 
#include 

qtLearn5PaintLine::qtLearn5PaintLine(QWidget *parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);

	// 实例QGraphicsScene
	QGraphicsScene *scene = new QGraphicsScene;

	// QPen 属性
	QPen pen;
	pen.setStyle(Qt::DashLine);// 虚线
	pen.setWidth(2);
	pen.setBrush(Qt::black);
	pen.setCapStyle(Qt::RoundCap);// 顶端是半圆形
	pen.setJoinStyle(Qt::RoundJoin);// 两条线之间有弧度，就是很圆滑

	// 绘制线条
	scene->addLine(30, 30, 200, 30, pen); // 起点的x y坐标,终点的x y坐标
	// 实例QGraphicsView
	QGraphicsView *view = new QGraphicsView(scene);
	// 显示
	this->setCentralWidget(view);
}

绘制椭圆

qtLearn5DrawLine.cpp:

#include "qtLearn5DrawLine.h"

#include 
#include 

qtLearn5DrawLine::qtLearn5DrawLine(QWidget* parent) : QMainWindow(parent) {
  ui.setupUi(this);

  // 实例 QGraphicsScene
  QGraphicsScene* scene = new QGraphicsScene;
  // 绘制椭圆
  scene->addEllipse(50, 50, 100, 120);  // 左上角x，y坐标，椭圆宽、高
  // 实例 QGraphicsView
  QGraphicsView* view = new QGraphicsView(scene);
  // 显示
  this->setCentralWidget(view);
}

qtLearn5DrawLine::~qtLearn5DrawLine() {}

显示静态图像

qtLearn5ShowStaticImage.h:

#pragma once

#include 
#include 

#include "ui_qtLearn5ShowStaticImage.h"

class qtLearn5ShowStaticImage : public QMainWindow {
  Q_OBJECT

 public:
  qtLearn5ShowStaticImage(QWidget *parent = nullptr);
  ~qtLearn5ShowStaticImage();

 protected:
  // paintEvent(QPaintEvent*)函数是QWidget类中的虚函数，用于ui的绘制，会在多种情况下被其他函数自动调用，比如update()时
  void paintEvent(QPaintEvent *);

 private:
  Ui::qtLearn5ShowStaticImageClass ui;
};

qtLearn5ShowStaticImage.cpp:

#include "qtLearn5ShowStaticImage.h"

qtLearn5ShowStaticImage::qtLearn5ShowStaticImage(QWidget *parent)
    : QMainWindow(parent) {
  ui.setupUi(this);
}

qtLearn5ShowStaticImage::~qtLearn5ShowStaticImage() {}

void qtLearn5ShowStaticImage::paintEvent(QPaintEvent *) {
  // 实例 QPixmap
  // 从路径的文件构造像素图。如果文件不存在或格式未知，则像素图变为空像素图
  QPixmap image(":/new/prefix/dog.png");
  // 实例 QPainter 绘制类
  QPainter painter(this);
  // 绘制图片
  painter.drawPixmap(20, 20, 200, 257, image);
}

显示动态图像

qtLearn5ShowDynamicImage.cpp:

#include "qtLearn5ShowDynamicImage.h"

#include 
#include 
#include 

qtLearn5ShowDynamicImage::qtLearn5ShowDynamicImage(QWidget *parent)
    : QMainWindow(parent) {
  ui.setupUi(this);

  // 实例 QLabel
  QLabel *label = new QLabel(this);
  label->setGeometry(QRect(50, 50, 88, 51));
  // 实例 QMovie
  QMovie *movie = new QMovie(":/new/prefix/img.gif");
  // 3 秒后图片消失
  QTimer::singleShot(3000, label, SLOT(close()));
  label->setMovie(movie);
  movie->start();
}

qtLearn5ShowDynamicImage::~qtLearn5ShowDynamicImage() {}

图片水平移动

qtLearn5PictureMoveHorizontal.h:

#pragma once

#include 
#include 
#include 
#include 

#include "ui_qtLearn5PictureMoveHorizontal.h"

class qtLearn5PictureMoveHorizontal : public QMainWindow {
  Q_OBJECT

 public:
  qtLearn5PictureMoveHorizontal(QWidget *parent = nullptr);
  ~qtLearn5PictureMoveHorizontal();

 private:
  Ui::qtLearn5PictureMoveHorizontalClass ui;

  QLabel *label;
  QImage *image;
  QPushButton *button;

 private slots:
  void moveImg();
};

qtLearn5PictureMoveHorizontal.cpp:

#include "qtLearn5PictureMoveHorizontal.h"

qtLearn5PictureMoveHorizontal::qtLearn5PictureMoveHorizontal(QWidget *parent)
    : QMainWindow(parent) {
  ui.setupUi(this);

  // 初始化 QLabel
  label = new QLabel(this);
  label->setGeometry(QRect(50, 50, 250, 150));

  // 实例 QImage
  image = new QImage;
  // QImage 加载图片
  image->load(":/new/prefix1/hd.png");
  // Label 显示图片
  label->setPixmap(QPixmap::fromImage(*image));

  // 实例 button
  button = new QPushButton(this);
  button->setGeometry(QRect(50, 250, 100, 50));
  button->setText(QString::fromLocal8Bit("移动"));
  connect(button, SIGNAL(clicked()), this, SLOT(moveImg()));
}

qtLearn5PictureMoveHorizontal::~qtLearn5PictureMoveHorizontal() {}

// 点击移动
int i = 60;
void qtLearn5PictureMoveHorizontal::moveImg() {
  // 移动 label 控件
  label->move(i, 50);
  i += 10;
}

图片翻转

qtLearnPictureReversal.h:

#pragma once
#pragma execution_character_set("utf-8")

#include 
#include 
#include 
#include 

#include "ui_qtLearnPictureReversal.h"

class qtLearnPictureReversal : public QMainWindow {
	Q_OBJECT

public:
	qtLearnPictureReversal(QWidget* parent = nullptr);
	~qtLearnPictureReversal();

private:
	Ui::qtLearnPictureReversalClass ui;

	QLabel* label;
	QImage* img;
	QPushButton* hBt;
	QPushButton* vBt;
	QPushButton* angleBt;

private slots:
	void hShow();
	void vShow();
	void angleShow();
};

qtLearnPictureReversal.cpp:

#include "qtLearnPictureReversal.h"

#include 

qtLearnPictureReversal::qtLearnPictureReversal(QWidget* parent)
	: QMainWindow(parent) {
	ui.setupUi(this);

	// 实例 QLabel
	label = new QLabel(this);
	label->setGeometry(QRect(160, 50, 2500, 150));

	// 实例 QImage
	img = new QImage;
	// Image 加载图片
	img->load(":/new/prefix/hd.png");
	// Label 显示图片
	label->setPixmap(QPixmap::fromImage(*img));

	// 实例水平操作按钮
	hBt = new QPushButton(this);
	hBt->setGeometry(QRect(50, 200, 80, 25));
	hBt->setText("水平翻转");
	connect(hBt, SIGNAL(clicked()), this, SLOT(hShow()));

	// 实例垂直操作按钮
	vBt = new QPushButton(this);
	vBt->setGeometry(QRect(160, 200, 80, 25));
	vBt->setText("垂直操作");
	connect(vBt, SIGNAL(clicked()), this, SLOT(vShow()));

	// 实例角度操作按钮 88°
	angleBt = new QPushButton(this);
	angleBt->setGeometry(QRect(270, 200, 80, 25));
	angleBt->setText("角度操作");
	connect(angleBt, SIGNAL(clicked()), this, SLOT(angleShow()));
}

qtLearnPictureReversal::~qtLearnPictureReversal() {}

// 水平操作
void qtLearnPictureReversal::hShow() {
	// 水平翻转
	*img = img->mirrored(true, false);
	// 显示图片
	label->setPixmap(QPixmap::fromImage(*img));
}


// 垂直操作
void qtLearnPictureReversal::vShow() {
	// 垂直翻转
	*img = img->mirrored(false, true);
	// 显示图片
	label->setPixmap(QPixmap::fromImage(*img));
}


// 角度操作
void qtLearnPictureReversal::angleShow() {
	QMatrix matrix;
	// 88 角度
	matrix.rotate(88);
	*img = img->transformed(matrix);
	// 显示图片
	label->setPixmap(QPixmap::fromImage(*img));
}

图片缩放

qtLearn5PictureResize.h:

#pragma once
#pragma execution_character_set("utf-8")

#include 
#include "ui_qtLearn5PictureResize.h"

#include 
#include 
#include 

class qtLearn5PictureResize : public QMainWindow
{
	Q_OBJECT

public:
	qtLearn5PictureResize(QWidget* parent = nullptr);
	~qtLearn5PictureResize();

private:
	Ui::qtLearn5PictureResizeClass ui;

	QLabel* label;
	QImage* img;
	QPushButton* bigBt;
	QPushButton* smallBt;

private slots:
	void bShow();
	void sShow();

};

qtLearn5PictureResize.cpp:

#include "qtLearn5PictureResize.h"

qtLearn5PictureResize::qtLearn5PictureResize(QWidget* parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);

	// 实例 QLabel
	label = new QLabel(this);
	label->setGeometry(QRect(160, 50, 250, 150));

	// 实例 QImage
	img = new QImage;
	// QImage 加载图片
	img->load(":/new/prefix/hd.png");
	// label 显示图片
	label->setPixmap(QPixmap::fromImage(*img));

	// 实例放大按钮
	bigBt = new QPushButton(this);
	bigBt->setGeometry(QRect(50, 200, 80, 25));
	bigBt->setText("放大");
	connect(bigBt, SIGNAL(clicked()), this, SLOT(bShow()));

	// 实例缩小按钮
	smallBt = new QPushButton(this);
	smallBt->setGeometry(QRect(260, 200, 80, 25));
	smallBt->setText("缩小");
	connect(smallBt, SIGNAL(clicked()), this, SLOT(sShow()));
}

qtLearn5PictureResize::~qtLearn5PictureResize()
{}

// 放大操作
void qtLearn5PictureResize::bShow()
{
	*img = img->scaled(100, 100, Qt::IgnoreAspectRatio);
	// 显示图片
	label->setPixmap(QPixmap::fromImage(*img));

}

// 缩小操作
void qtLearn5PictureResize::sShow()
{
	*img = img->scaled(60, 60, Qt::IgnoreAspectRatio);
	// 显示图片
	label->setPixmap(QPixmap::fromImage(*img));
}

图片中加文字

qtLearn5PictureAddCharacter.cpp:

#include "qtLearn5PictureAddCharacter.h"

#include 
#include 
#include 

qtLearn5PictureAddCharacter::qtLearn5PictureAddCharacter(QWidget* parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);

	// 实例 QLabel
	QLabel* label = new QLabel(this);
	label->setGeometry(QRect(50, 50, 300, 250));
	//label->setText("图片已经生成，保存在项目文件中[text.jpg]。");

	// 实例 QImage
	QImage image = QPixmap(":/new/prefix/bg.png").toImage();
	// 实例 QPainter
	QPainter painter(&image);
	// 设置画刷模式
	painter.setCompositionMode(QPainter::CompositionMode_SourceIn);
	// 改变画笔和字体
	QPen pen = painter.pen();
	pen.setColor(Qt::red);
	QFont font = painter.font();
	font.setBold(true); // 加粗
	font.setPixelSize(25); // 改变字体大小
	painter.setPen(pen);
	painter.setFont(font);
	// 将文字绘制在图片中心位置
	painter.drawText(image.rect(), Qt::AlignCenter, "你好，朋友");
	// 这个为这个图片压缩度 0/100
	int n = 100;
	// 保存图片
	image.save("text.jpg", "JPG", n);
	label->setPixmap(QPixmap::fromImage(image));
}

qtLearn5PictureAddCharacter::~qtLearn5PictureAddCharacter()
{}

图像扭曲

qtLearn5PictureWarp.h:

#pragma once

#include 
#include 

#include "ui_qtLearn5PictureWarp.h"

class qtLearn5PictureWarp : public QMainWindow
{
    Q_OBJECT

public:
    qtLearn5PictureWarp(QWidget *parent = nullptr);
    ~qtLearn5PictureWarp();

protected:
    void paintEvent(QPaintEvent*);

private:
    Ui::qtLearn5PictureWarpClass ui;
};

qtLearn5PictureWarp.cpp:

#include "qtLearn5PictureWarp.h"

#include 

qtLearn5PictureWarp::qtLearn5PictureWarp(QWidget* parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);
}

qtLearn5PictureWarp::~qtLearn5PictureWarp()
{}

void qtLearn5PictureWarp::paintEvent(QPaintEvent*)
{
	// 实例 QPainter
	QPainter painter(this);
	// 实例 QPixmap
	QPixmap pix;
	// 加载图片
	pix.load(":/new/prefix/bg.png");
	// 原图显示
	painter.drawPixmap(0, 50, 183, 160, pix);
	// 扭曲
	painter.shear(0.5, 0); // 横向扭曲
	// 绘制扭曲图
	painter.drawPixmap(190, 50, 183, 160, pix);
}

模糊效果

qtLearn5Blur.cpp:

#include "qtLearn5Blur.h"

#include 
#include 

qtLearn5Blur::qtLearn5Blur(QWidget* parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);

	// 实例 QLabel
	QLabel* label = new QLabel(this);
	// QLabel 位置
	label->setGeometry(QRect(50, 50, 254, 153));
	// 实例 QImage
	QImage* img = new QImage;
	// 加载图片
	img->load(":/new/prefix/yu.png");
	label->setPixmap(QPixmap::fromImage(*img));
	// 实例 QGraphicsBlurEffect
	QGraphicsBlurEffect* effrct = new QGraphicsBlurEffect(this);
	// 模糊值 值越大越模糊
	effrct->setBlurRadius(5);
	label->setGraphicsEffect(effrct);
}

qtLearn5Blur::~qtLearn5Blur()
{}

着色效果

qtLearn5Coloration.cpp:

#include "qtLearn5Coloration.h"

#include 
#include 

qtLearn5Coloration::qtLearn5Coloration(QWidget* parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);

	// 实例 QLabel
	QLabel* label = new QLabel(this);
	// QLabel 位置
	label->setGeometry(QRect(50, 50, 254, 153));
	// 实例 QImage
	QImage* img = new QImage;
	// 加载图片
	img->load(":/new/prefix/yu.png");
	label->setPixmap(QPixmap::fromImage(*img));
	// 实例 QGraphicsColorizeEffect
	QGraphicsColorizeEffect* effect = new QGraphicsColorizeEffect(this);
	// 设定着色
	effect->setColor(QColor(0, 0, 192));
	label->setGraphicsEffect(effect);
}

qtLearn5Coloration::~qtLearn5Coloration()
{}

阴影效果

qtLearn5Shadows.cpp:

#include "qtLearn5Shadows.h"

#include 
#include 

qtLearn5Shadows::qtLearn5Shadows(QWidget* parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);

	// 实例 QLabel
	QLabel* label = new QLabel(this);
	// QLabel 位置 
	label->setGeometry(QRect(50, 50, 254, 153));
	// 实例 QImage
	QImage* img = new QImage;
	// 加载图片
	img->load(":/new/prefix/yu.png");
	label->setPixmap(QPixmap::fromImage(*img));
	// 实例 QGraphicsDropShadowEffect
	QGraphicsDropShadowEffect* effect = new QGraphicsDropShadowEffect(this);
	// 设定阴影
	effect->setOffset(8, 8);
	label->setGraphicsEffect(effect);
}

qtLearn5Shadows::~qtLearn5Shadows()
{}

透明效果

qtLearn5TransparentEffect.cpp:

#include "qtLearn5TransparentEffect.h"
#include 
#include 

qtLearn5TransparentEffect::qtLearn5TransparentEffect(QWidget* parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);

	// 实例 QLabel
	QLabel* label = new QLabel(this);
	// QLabel 位置
	label->setGeometry(QRect(50, 50, 254, 153));
	// 实例 QImage
	QImage* img = new QImage;
	// 加载图片
	img->load(":/new/prefix/yu.png");
	label->setPixmap(QPixmap::fromImage(*img));
	// 实例 QGraphicsOpacityEffect
	QGraphicsOpacityEffect* effect = new QGraphicsOpacityEffect(this);
	// 设置透明值
	effect->setOpacity(0.5);
	label->setGraphicsEffect(effect);
}

qtLearn5TransparentEffect::~qtLearn5TransparentEffect() {}

多媒体应用

音频、视频播放器

CONFIG += qaxcontainer

HEADERS = playerwindow.h

在vs中Qt Projrct Setting的Qt Model中勾选Active Qt(Container)

qtLearn6MovePlayer.h:

#pragma once
#pragma execution_character_set("utf-8")

#include 
#include 
#include 
#include 
#include 

#include "ui_qtLearn6MovePlayer.h"

class qtLearn6MovePlayer : public QMainWindow {
    Q_OBJECT
  public:
    qtLearn6MovePlayer(QWidget* parent = nullptr);
    ~qtLearn6MovePlayer();

    // 播放状态 枚举类型
    enum PlayStateConstants { Stopped = 0, Paused = 1, Playing = 2 };

    enum ReadyStateConstants {
        Uninitialized = 0,
        Loading       = 1,
        Interactive   = 3,
        Complete      = 4
    };
    // Q_ENUMS() 宏的参数是枚举类型
    Q_ENUMS(ReadyStateConstants)

  protected:
    // 播放进度
    void timerEvent(QTimerEvent* event);

  private:
    Ui::qtLearn6MovePlayerClass ui;

    QAxWidget*   axWidget;         // 播放器
    QToolButton* openButton;       // 浏览按钮
    QToolButton* playPauseButton;  // 暂停播放按钮
    QToolButton* stopButton;       // 停止播放按钮
    QSlider*     seekSlider;       // 进度条
    QString      fileFilters;      // 文件格式
    int          updateTimer;      // 播放进度
    QWidget*     widget;           // QWidget

  private slots:
    void openFile();
    void onPlayStateChange(int oldState, int newState);
    void onReadyStateChange(ReadyStateConstants readyState);
    void onPositionChange(double oldPos, double newPos);
    void sliderValueChanged(int newValue);
};

qtLearn6MovePlayer.cpp:

#include "qtLearn6MovePlayer.h"

#include 
#include 
#include 

qtLearn6MovePlayer::qtLearn6MovePlayer(QWidget* parent) : QMainWindow(parent)
{
    ui.setupUi(this);

    // 实例 QAxWidget（播放器插件）
    axWidget = new QAxWidget;

    // 注册表键值，调用插件
    /*
     * 老版本ID "22D6F312-B0F6-11D0-94AB-0080C74C7E95" (Windows Media
     * Player 6.4)，向后兼容
     * 新版本ID "6BF52A52-394A-11D3-B153-00C04F79FAA6" (Windows Media Player 10)
     */
    axWidget->setControl("{22D6F312-B0F6-11D0-94AB-0080C74C7E95}");
    axWidget->setProperty("ShowControls", false);
    axWidget->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
    connect(axWidget, SIGNAL(PlayStateChange(int, int)), this,
            SLOT(onPlayStateChange(int, int)));
    connect(axWidget, SIGNAL(ReadyStateChange(ReadyStateConstants)), this,
            SLOT(onReadyStateChange(ReadyStateConstants)));
    connect(axWidget, SIGNAL(PositionChange(double, double)), this,
            SLOT(onPositionChange(double, double)));

    // 实例打开文件按钮
    openButton = new QToolButton;
    openButton->setText(tr("浏览.."));
    connect(openButton, SIGNAL(clicked()), this, SLOT(openFile()));

    // 实例播放暂停按钮
    playPauseButton = new QToolButton;
    playPauseButton->setText(tr("播放"));
    playPauseButton->setEnabled(false);  // 按钮不可点击
    connect(playPauseButton, SIGNAL(clicked()), axWidget, SLOT(Play()));

    // 停止按钮
    stopButton = new QToolButton;
    stopButton->setText(tr("停止"));
    stopButton->setEnabled(false);
    connect(stopButton, SIGNAL(clicked()), axWidget, SLOT(Stop()));

    // 进度条
    seekSlider = new QSlider(Qt::Horizontal);
    seekSlider->setEnabled(false);
    connect(seekSlider, SIGNAL(valueChange(int)), this,
            SLOT(sliderValueChanged(int)));
    connect(seekSlider, SIGNAL(sliderPressed()), axWidget, SLOT(Pause()));

    // 可播放格式 此处简写下面几个
    fileFilters = tr("Video file (*.mpg *.mpeg *.avi *.wmv *.mp4)\n"
                     "Audio files (*.mp3 *.wav)");
    // 初始化播放速度
    updateTimer = 0;

    // 三个按钮横向布局
    QHBoxLayout* buttonLayout = new QHBoxLayout;
    buttonLayout->addWidget(openButton);
    buttonLayout->addWidget(playPauseButton);
    buttonLayout->addWidget(stopButton);

    // 纵向布局 上面播放器下面三个按钮
    QVBoxLayout* mainLayout = new QVBoxLayout;
    mainLayout->addWidget(axWidget);
    mainLayout->addLayout(buttonLayout);
    mainLayout->addWidget(seekSlider);

    // 显示布局控件
    widget = new QWidget();
    widget->setLayout(mainLayout);
    this->setCentralWidget(widget);
}

qtLearn6MovePlayer::~qtLearn6MovePlayer() {}

// 进度条随播放器移动
void qtLearn6MovePlayer::timerEvent(QTimerEvent* event)
{
    if (event->timerId() == updateTimer) {
        double curPos = axWidget->property("CurrentPosition").toDouble();
        onPositionChange(-1, curPos);
    }
    else {
        QWidget::timerEvent(event);
    }
}

// 选择音频视频文件
void qtLearn6MovePlayer::openFile()
{
    // 定义 QString 变量接受文件
    QString fileName =
        QFileDialog::getOpenFileName(this, tr("Select File"), ".", fileFilters);
    // 如果文件不为空 则播放
    if (!fileName.isEmpty()) {
        axWidget->setProperty("FileName", QDir::toNativeSeparators(fileName));
    }
}

void qtLearn6MovePlayer::onPlayStateChange(int oldState, int newState)
{
    playPauseButton->disconnect(axWidget);

    switch (newState) {
        case Stopped:
            if (updateTimer) {
                killTimer(updateTimer);
                updateTimer = 0;
            }

        case Paused:
            connect(playPauseButton, SIGNAL(clicked()), axWidget, SLOT(Play()));
            stopButton->setEnabled(false);
            playPauseButton->setText(tr("播放"));
            break;

        case Playing:
            if (!updateTimer) {
                updateTimer = startTimer(100);
            }
            connect(playPauseButton, SIGNAL(clicked()), axWidget,
                    SLOT(Paused()));
            stopButton->setEnabled(true);
            playPauseButton->setText(tr("暂停"));
    }
}

void qtLearn6MovePlayer::onReadyStateChange(ReadyStateConstants readyState)
{
    if (readyState == Complete) {
        double duration = 60 * axWidget->property("DUration").toDouble();
        seekSlider->setMinimum(0);
        seekSlider->setMaximum(int(duration));
        seekSlider->setEnabled(true);
        playPauseButton->setEnabled(true);
    }
}

void qtLearn6MovePlayer::onPositionChange(double oldPos, double newPos)
{
    seekSlider->blockSignals(true);
    seekSlider->setValue(int(newPos * 60));
    seekSlider->blockSignals(false);
}

void qtLearn6MovePlayer::sliderValueChanged(int newValue)
{
    seekSlider->blockSignals(true);
    axWidget->setProperty("CurrentPosition", double(newValue) / 60);
    seekSlider->blockSignals(false);
}

[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-ewJZj21X-1664264171658)(…/images/image-20220815162202829.png)]

使用 “6BF52A52-394A-11D3-B153-00C04F79FAA6” Windows Media Player 10：

播放 Flash 动画

qtLearn5FlashPlayer.cpp：

#include "qtLearn5FlashPlayer.h"

#include 
#include 
#include 
#include 

qtLearn5FlashPlayer::qtLearn5FlashPlayer(QWidget* parent) : QMainWindow(parent)
{
    ui.setupUi(this);

    // 实例 QAxWidget
    QAxWidget* flash = new QAxWidget(0, 0);
    // 显示大小
    flash->resize(460, 370);  // 设置该空间的初始大小
    // 设置注册表键值 调用 ActiveX 插件
    flash->setControl(
        QString::fromUtf8("{d27cdb6e-ae6d-11cf-96b8-444553540000}"));
    // 设置控制器
    // 文件路径 注意如果发布可执行文件 播放文字路劲需要拷贝一份
    flash->dynamicCall("LoadMove(long,string)", 0,
                       QDir::currentPath() + "/flash/map.swf");
    // 纵向布局
    QVBoxLayout* layout = new QVBoxLayout;
    // 布局填充 QAxWidget
    layout->addWidget(flash);
    // 实例 QWidget
    QWidget* widget = new QWidget();
    widget->setLayout(layout);
    // 界面显示
    this->setCentralWidget(widget);
    // 界面标题为路劲注意查看路径
    this->setWindowTitle(QDir::currentPath());
}

qtLearn5FlashPlayer::~qtLearn5FlashPlayer() {}

flash不支持64位，且需要安装FlashActiveX插件

播放图片动画

qtLearn6ImagePlayer.h:

#pragma once

#include 
#include 
#include 
#include 

#include "ui_qtLearn6ImagePlayer.h"

class qtLearn6ImagePlayer : public QMainWindow {
    Q_OBJECT

  public:
    qtLearn6ImagePlayer(QWidget* parent = nullptr);
    ~qtLearn6ImagePlayer();

  private:
    Ui::qtLearn6ImagePlayerClass ui;

    QPixmap* pm;
    QLabel*  label;
    QTimer*  timer;

  private slots:
    void changeImg();
};

qtLearn6ImagePlayer.cpp:

#include "qtLearn6ImagePlayer.h"
#include 

qtLearn6ImagePlayer::qtLearn6ImagePlayer(QWidget* parent) : QMainWindow(parent)
{
    ui.setupUi(this);

    //实例 QPixmap
    pm = new QPixmap;
    //加载第一张图片
    pm->load(":/image/a0");
    //实例 QLabel
    label = new QLabel(this);
    //位置
    label->setGeometry(QRect(50, 50, 350, 150));
    // Label 加载 QPixmap
    label->setPixmap(*pm);
    //实例 QTimer
    timer = new QTimer;
    //事件
    connect(timer, SIGNAL(timeout()), this, SLOT(changeImg()));
    //启动 QTimer
    timer->start(100);
}

qtLearn6ImagePlayer::~qtLearn6ImagePlayer() {}

//初始值
int  i = -1;
void qtLearn6ImagePlayer::changeImg()
{
    // i 不可大于 7，因为只准备了 8 张图片，i 从 0 开始。
    if (i < 7) {
        //每次 QTimer 执行 i+1；
        i++;
        //资源文件图片变量
        QString str = ":/image/a" + QString::number(i);
        //加载图片路径
        pm->load(str.toUtf8());
        // QLabel 显示图片
        label->setPixmap(*pm);
    }
    else {
        //循环一圈后，回到初始值，继续执行。
        i = -1;
    }
}

操作系统

获取屏幕分辨率

qtLearn7ScreenResolution.cpp:

#include "qtLearn7ScreenResolution.h"

#include 
#include 

qtLearn7ScreenResolution::qtLearn7ScreenResolution(QWidget* parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

    // 实例 QLabel
    QLabel* label = new QLabel(this);
    // QLabel 位置
    label->setGeometry(QRect(50, 50, 250, 25));
    // 实例 QDesktopWidget
    QDesktopWidget* desktopWidget = QApplication::desktop();
    // 实例 QRect 接受屏幕信息
    QRect screenRect = desktopWidget->screenGeometry();
    // 定义字符串
    QString str = "屏幕分辨率为: ";
    // 屏幕宽度
    int sWidth = screenRect.width();
    // 屏幕高度
    int sHeight = screenRect.height();
    // 输出结果
    label->setText(
        str + QString::number(sWidth, 10) + " " +
        QString::number(sHeight, 10));  // QString::number 第二个参数转换进制
}

qtLearn7ScreenResolution::~qtLearn7ScreenResolution() {}

注：

用 Qt5 之前的编译版本，Qt 6.0 及之后版本，QDesktopWidget 已从 QtWidgets 模块中被彻底移除，可使用 QtGui::QScreen 代替 QtWidgets::QDesktopWidget

获取本机名、IP地址

qtLearn7GetAddressByLocalhost.cpp:

#pragma execution_character_set("utf-8")

#include "qtLearn7GetAddressByLocalhost.h"

#include 
#include 

qtLearn7GetAddressByLocalhost::qtLearn7GetAddressByLocalhost(QWidget* parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

    // 获取计算机名称
    QString localHostName = QHostInfo::localHostName();
    qDebug() << "计算机名: " << localHostName;

    // 遍历 IP 地址
    QHostInfo info = QHostInfo::fromName(localHostName);
    // 遍历地址，只获取 IPV4 地址
    foreach (QHostAddress address, info.addresses()) {
        if (address.protocol() == QAbstractSocket::IPv4Protocol) {
            qDebug() << "ipv4地址: " << address.toString();
        }
    }
}

qtLearn7GetAddressByLocalhost::~qtLearn7GetAddressByLocalhost() {}

输出：

计算机名:  "wgq"
ipv4地址:  "192.168.1.2"

根据网址获取IP地址

qt 添加 network 模块

qtLraen7GetIPAddress.h:

#pragma once
#pragma execution_character_set("utf-8")

#include 
#include 
#include 
#include 
#include 

#include "ui_qtLraen7GetIPAddress.h"

class qtLraen7GetIPAddress : public QMainWindow {
    Q_OBJECT

  public:
    qtLraen7GetIPAddress(QWidget* parent = nullptr);
    ~qtLraen7GetIPAddress();

  private:
    Ui::qtLraen7GetIPAddressClass ui;

    QLabel*      label;
    QPushButton* button;
    QLineEdit*   edit;
    QLabel*      result;

  private slots:
    void sendUrl();
    void lookedUp(const QHostInfo& host);
};

qtLraen7GetIPAddress.cpp:

#include "qtLraen7GetIPAddress.h"

#include 

qtLraen7GetIPAddress::qtLraen7GetIPAddress(QWidget* parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

    // 实例 QLabel
    label = new QLabel(this);
    label->setGeometry(QRect(50, 50, 40, 25));
    label->setText("网址: ");

    // 实例 QLineEdit
    edit = new QLineEdit(this);
    edit->setGeometry(QRect(100, 50, 150, 25));
    edit->setText("www.baidu.com");

    // 实例 QPushButton
    button = new QPushButton(this);
    button->setGeometry(QRect(260, 50, 80, 25));
    button->setText("查询");
    connect(button, SIGNAL(clicked()), this, SLOT(sendUrl()));

    // 实例 QLabel
    result = new QLabel(this);
    result->setGeometry(QRect(50, 90, 250, 25));
}

qtLraen7GetIPAddress::~qtLraen7GetIPAddress() {}

void qtLraen7GetIPAddress::sendUrl()
{
    QHostInfo::lookupHost(edit->text(), this, SLOT(lookedUp(QHostInfo)));
}

void qtLraen7GetIPAddress::lookedUp(const QHostInfo& host)
{
    result->setText("IP地址: " + host.addresses().first().toString());
}

判断键盘按下键值

QtLearn7JudgeKey.h

#pragma once
#pragma execution_character_set("utf-8")

#include 
#include 

#include "ui_QtLearn7JudgeKey.h"

class QtLearn7JudgeKey : public QMainWindow {
    Q_OBJECT

  public:
    QtLearn7JudgeKey(QWidget* parent = nullptr);
    ~QtLearn7JudgeKey();

    // 键盘事件方法
    void keyPressEvent(QKeyEvent* event);

  private:
    Ui::QtLearn7JudgeKeyClass ui;

    QLabel* label;
};

QtLearn7JudgeKey.cpp:

#include "QtLearn7JudgeKey.h"

#include 

QtLearn7JudgeKey::QtLearn7JudgeKey(QWidget* parent) : QMainWindow(parent)
{
    ui.setupUi(this);

    // 实例 QLabel
    label = new QLabel(this);
    label->setGeometry(QRect(50, 50, 200, 25));
    label->setText("按Q键改变文字");
}

QtLearn7JudgeKey::~QtLearn7JudgeKey() {}

// 键盘事件
void QtLearn7JudgeKey::keyPressEvent(QKeyEvent* event)
{
    // 键值如果等于Q
    if (event->key() == Qt::Key_Q) {
        label->setText("你按下了Q键");
    }
}

获取系统环境变量

QtLearn7GetSystemEnvironVariables.cpp:

#pragma execution_character_set("utf-8")

#include "QtLearn7GetSystemEnvironVariables.h"

#include 
#include 
#include 

QtLearn7GetSystemEnvironVariables::QtLearn7GetSystemEnvironVariables(
    QWidget* parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

    // 标题
    this->setWindowTitle("获取Path环境变量");
    // 实例 QListView
    QListView* listView = new QListView(this);
    // QListView 位置
    listView->setGeometry(QRect(10, 15, 450, 350));
    // 实例 QStringList 接受 path 系统变量
    QStringList strList = QProcess::systemEnvironment();
    // 装载数据模型
    QStringListModel* model = new QStringListModel(strList);
    // 绑定数据
    listView->setModel(model);
}

QtLearn7GetSystemEnvironVariables::~QtLearn7GetSystemEnvironVariables() {}

执行系统命令

QtLearn7RunSystemCommand.h:

#pragma once
#pragma execution_character_set("utf-8")

#include "ui_QtLearn7RunSystemCommand.h"
#include 
#include 
#include 
#include 
#include 
#include 

class QtLearn7RunSystemCommand : public QMainWindow {
    Q_OBJECT

  public:
    QtLearn7RunSystemCommand(QWidget* parent = nullptr);
    ~QtLearn7RunSystemCommand();

  private:
    Ui::QtLearn7RunSystemCommandClass ui;

    QLineEdit*      comn;     // dos 命令输入框
    QPlainTextEdit* outEdit;  // 命令执行反馈框
    QPushButton*    btClick;  // 执行按钮
    QProcess*       process;  // QProcess
    QString         output;   // 接受反馈信息
    QLabel*         label;

  private slots:
    void clickExecution();  // 点击按钮事件
    void readOutput();      // QProcess 事件
};

QtLearn7RunSystemCommand.cpp:

#include "QtLearn7RunSystemCommand.h"

QtLearn7RunSystemCommand::QtLearn7RunSystemCommand(QWidget* parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

    // 实例命令输入框
    comn = new QLineEdit(this);
    comn->setText("ipconfig");
    comn->setGeometry(QRect(20, 20, 260, 25));

    // 实例执行按钮
    btClick = new QPushButton(this);
    btClick->setText("执行");
    btClick->setGeometry(QRect(290, 20, 80, 25));
    connect(btClick, SIGNAL(clicked()), this, SLOT(clickExecution()));

    // 实例输出对话框
    outEdit = new QPlainTextEdit(this);
    outEdit->setGeometry(QRect(20, 60, 450, 200));

    // 实例 QProcess
    process = new QProcess;
    connect(process, SIGNAL(readyRead()), this, SLOT(readOutput()));

    // dos 命令查阅
    label = new QLabel(this);
    label->setGeometry(QRect(30, 265, 200, 25));
    label->setText(tr(
        "命令DOS查阅"));
    // 开启超链接
    label->setOpenExternalLinks(true);
}

QtLearn7RunSystemCommand::~QtLearn7RunSystemCommand() {}

// 执行 DOS 命令
void QtLearn7RunSystemCommand::clickExecution()
{
    // 定义变量接受 dos 命令
    QString info = comn->text();
    // 执行命令
    process->start(info);
    // 绑定反馈值
    // outEdit->setPlainText(output);
}

// QProcess 事件
void QtLearn7RunSystemCommand::readOutput()
{
    // 接受反馈信息
    output += QString::fromLocal8Bit(process->readAll());
    // 将返回值绑定控件
    outEdit->setPlainText(output);
}

注册表

写入注册表

QtLearn8WriteRegedit.cpp:

#pragma execution_character_set("utf-8")

#include "QtLearn8WriteRegedit.h"
#include 

QtLearn8WriteRegedit::QtLearn8WriteRegedit(QWidget* parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

    // 实例 QSettings
    // 参数 1：注册表位置
    // 参数 2：操作 windows 注册表 QSettings::NativeFormat
    // 说明：QSettings::IniFormat 读写 ini 格式的配置文件
    QSettings* reg = new QSettings("HKEY_CURRENT_USER\\Software\\Qt01",
                                   QSettings::NativeFormat);

    // 设定值有修改，没有创建
    reg->setValue("键名001", "值001");
    reg->setValue("键名002", true);
    // 用完删除QSettings
    delete reg;
}

QtLearn8WriteRegedit::~QtLearn8WriteRegedit() {}

查找注册表

QtLraen8FindRegedit.cpp:

#pragma execution_character_set("utf-8")
#include "QtLraen8FindRegedit.h"

#include 
#include 

QtLraen8FindRegedit::QtLraen8FindRegedit(QWidget* parent) : QMainWindow(parent)
{
    ui.setupUi(this);

    // 输出键值
    QLabel* label = new QLabel(this);
    label->setGeometry(QRect(50, 50, 200, 25));

    // 实例 QSettings
    // 参数 1：注册表在前面注册的QT001
    QSettings* reg = new QSettings("HKEY_CURRENT_USER\\Software\\Qt01",
                                   QSettings::NativeFormat);
    // 判断 value 是否为空，不为空则输出
    if (reg->value("键名001") != "") {
        QString str = reg->value("键名001").toString();
        label->setText("键名001::" + reg->value("键名001").toString());
    }
    // 删除 QSettings
    delete reg;
}

QtLraen8FindRegedit::~QtLraen8FindRegedit() {}

修改 IE 浏览器的默认主页

想要修改注册表中软件的信息，首先需要找到该软件对应的键，例：IE键路径如下：[HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main]子项，找到名称为“Start Page”的项

QtLearn8RemoveIEHome.cpp:

#include "QtLearn8RemoveIEHome.h"
#include 

QtLearn8RemoveIEHome::QtLearn8RemoveIEHome(QWidget* parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

    // 实例 QSettings
    QSettings* reg = new QSettings(
        "HKEY_CURRENT_USER\\Software\\Microsoft\\Internet Explorer\\Main",
        QSettings::NativeFormat);
    // 判断value是否为空，不为空则输出
    if (reg->value("Start Page") != "") {
        // IE 默认主页修改为百度
        reg->setValue("Start Page", "http://www.baidu.com");
    }
    // 删除 QSettings
    delete reg;
}

QtLearn8RemoveIEHome::~QtLearn8RemoveIEHome() {}

数据库

安装 sqlite3 并配置环境：

在.pro工程文件加sql:

MainWindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;

private slots:
    void initDb();
    void createTable();
    void insertRecord(const QString &name, int age);
    void deleteRecord(const QString &name);
    void updateRecord(const QString &name, int age);
    int searchRecord(const QString &name);
};
#endif // MAINWINDOW_H

MainWindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"


#include 
#include 
#include 
#include 

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    initDb();

}

// 表的初始化
void MainWindow::initDb()
{
    qDebug()<



注：

lastError 输出sql错误信息

#include 
...
QSqlQuery query;
qDebug() << "init table error" << query.lastError();


查询数据需要next、first

查询语句的结果需要next或first才能得到第一条数据，否则record停留在上一条记录
	QSqlQuery query;	
	const QString sql = R"(SELECT age FROM my_table WHERE name='%1';
    
    if(query.exec(sql.arg(name))){
    	...sqlerror
    } else {
    	if (query.next()){
    		...success...
    	} else {
    		...no select...
    	}
    }


查询数据库驱动
qtLearn9QueryDBDriver.cpp:
#include "qtLearn9QueryDBDriver.h"
#include 
#include 
#include 

qtLearn9QueryDBDriver::qtLearn9QueryDBDriver(QWidget* parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

    // 实例 QStringList 接收驱动信息
    QStringList drivers = QSqlDatabase::drivers();
    // 循环输出
    foreach (QString driver, drivers) {
        qDebug() << "\r" << driver;
    }
}

qtLearn9QueryDBDriver::~qtLearn9QueryDBDriver() {}


输出：
 "QSQLITE"

 "QODBC"

 "QODBC3"

 "QPSQL"

 "QPSQL7"

网络开发
TCP服务端
MainWindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow {
    Q_OBJECT

  public:
    explicit MainWindow(QWidget* parent = nullptr);
    ~MainWindow();

  signals:
    void newMessage(QString);
  private slots:
    void newConnection();
    void appendToSocketList(QTcpSocket* socket);

    void readSocket();
    void discardSocket();
    void displayError(QAbstractSocket::SocketError socketError);

    void displayMessage(const QString& str);
    void sendMessage(QTcpSocket* socket);
    void sendAttachment(QTcpSocket* socket, QString filePath);

    void on_pushButton_sendMessage_clicked();
    void on_pushButton_sendAttachment_clicked();

    void refreshComboBox();

  private:
    Ui::MainWindow* ui;

    QTcpServer*       m_server;        // 服务器指针
    QSet connection_set;  // 客户端连接列表
};

#endif  // MAINWINDOW_H


MainWindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget* parent)
    : QMainWindow(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    m_server = new QTcpServer();

    // 监听
    if (m_server->listen(QHostAddress::Any, 8080)) {
        connect(this, &MainWindow::newMessage, this,
                &MainWindow::displayMessage);  // 监听消息
        connect(m_server, &QTcpServer::newConnection, this,
                &MainWindow::newConnection);  // 监听连接
        ui->statusBar->showMessage("Server is listening...");
    }
    else {
        QMessageBox::critical(this, "QTCPServer",
                              QString("Unable to start the server: %1.")
                                  .arg(m_server->errorString()));
        exit(EXIT_FAILURE);
    }
}

MainWindow::~MainWindow()
{
    foreach (QTcpSocket* socket, connection_set) {
        socket->close();
        socket->deleteLater();
    }

    m_server->close();
    m_server->deleteLater();

    delete ui;
}

// 客户端建立新连接
void MainWindow::newConnection()
{
    while (m_server->hasPendingConnections())
        appendToSocketList(m_server->nextPendingConnection());
}

// 新客户端绑定服务器连接
void MainWindow::appendToSocketList(QTcpSocket* socket)
{
    connection_set.insert(socket);
    connect(socket, &QTcpSocket::readyRead, this, &MainWindow::readSocket);
    connect(socket, &QTcpSocket::disconnected, this,
            &MainWindow::discardSocket);
    connect(socket, &QAbstractSocket::errorOccurred, this,
            &MainWindow::displayError);
    ui->comboBox_receiver->addItem(QString::number(socket->socketDescriptor()));
    displayMessage(
        QString("INFO :: Client with sockd:%1 has just entered the room")
            .arg(socket->socketDescriptor()));
}

// 读取传过来的数据
void MainWindow::readSocket()
{
    QTcpSocket* socket = reinterpret_cast(sender());

    QByteArray buffer;

    QDataStream socketStream(socket);
    // 当操作复杂数据类型时，我们就要确保读取和写入时的QDataStream版本是一样的
    // 如果你需要向前和向后兼容，可以在代码中使用硬编码指定流的版本号
    socketStream.setVersion(QDataStream::Qt_5_15);

    socketStream.startTransaction();
    socketStream >> buffer;  // 获取数据流的头

    if (!socketStream.commitTransaction()) {
        QString message = QString("%1 :: Waiting for more data to come..")
                              .arg(socket->socketDescriptor());
        emit newMessage(message);
        return;
    }

    // 拆分头判断数据类型
    QString header   = buffer.mid(0, 128);
    QString fileType = header.split(",")[0].split(":")[1];

    buffer = buffer.mid(128);

    if (fileType == "attachment") {
        QString fileName = header.split(",")[1].split(":")[1];
        QString ext      = fileName.split(".")[1];
        QString size     = header.split(",")[2].split(":")[1].split(";")[0];

        if (QMessageBox::Yes ==
            QMessageBox::question(
                this, "QTCPServer",
                QString("You are receiving an attachment from sd:%1 of size: "
                        "%2 bytes, called %3. Do you want to accept it?")
                    .arg(socket->socketDescriptor())
                    .arg(size)
                    .arg(fileName))) {
            QString filePath = QFileDialog::getSaveFileName(
                this, tr("Save File"),
                QStandardPaths::writableLocation(
                    QStandardPaths::DocumentsLocation) +
                    "/" + fileName,
                QString("File (*.%1)").arg(ext));

            QFile file(filePath);
            if (file.open(QIODevice::WriteOnly)) {
                file.write(buffer);
                QString message =
                    QString("INFO :: Attachment from sd:%1 successfully stored "
                            "on disk under the path %2")
                        .arg(socket->socketDescriptor())
                        .arg(QString(filePath));
                emit newMessage(message);
            }
            else
                QMessageBox::critical(
                    this, "QTCPServer",
                    "An error occurred while trying to write the attachment.");
        }
        else {
            QString message = QString("INFO :: Attachment from sd:%1 discarded")
                                  .arg(socket->socketDescriptor());
            emit newMessage(message);
        }
    }
    else if (fileType == "message") {
        QString message =
            QString("%1 :: %2")
                .arg(socket->socketDescriptor())
                .arg(QString::fromStdString(buffer.toStdString()));
        emit newMessage(message);
    }
}

// 客户端断开连接
void MainWindow::discardSocket()
{
    QTcpSocket* socket             = reinterpret_cast(sender());
    QSet::iterator it = connection_set.find(socket);
    if (it != connection_set.end()) {
        displayMessage(QString("INFO :: A client has just left the room")
                           .arg(socket->socketDescriptor()));
        connection_set.remove(*it);
    }
    refreshComboBox();

    socket->deleteLater();
}

// 处理异常 错误弹窗
void MainWindow::displayError(QAbstractSocket::SocketError socketError)
{
    switch (socketError) {
        case QAbstractSocket::RemoteHostClosedError: break;
        case QAbstractSocket::HostNotFoundError:
            QMessageBox::information(this, "QTCPServer",
                                     "The host was not found. Please check the "
                                     "host name and port settings.");
            break;
        case QAbstractSocket::ConnectionRefusedError:
            QMessageBox::information(
                this, "QTCPServer",
                "The connection was refused by the peer. Make sure QTCPServer "
                "is running, and check that the host name and port settings "
                "are correct.");
            break;
        default:
            QTcpSocket* socket = qobject_cast(sender());
            QMessageBox::information(
                this, "QTCPServer",
                QString("The following error occurred: %1.")
                    .arg(socket->errorString()));
            break;
    }
}

// 服务器发送消息
void MainWindow::on_pushButton_sendMessage_clicked()
{
    QString receiver = ui->comboBox_receiver->currentText();

    // 发送给所有客户端
    if (receiver == "Broadcast") {
        foreach (QTcpSocket* socket, connection_set) {
            sendMessage(socket);
        }
    }
    //发送给指定客户端
    else {
        foreach (QTcpSocket* socket, connection_set) {
            if (socket->socketDescriptor() == receiver.toLongLong()) {
                sendMessage(socket);
                break;
            }
        }
    }
    ui->lineEdit_message->clear();
}

// 服务器发送文件
void MainWindow::on_pushButton_sendAttachment_clicked()
{
    QString receiver = ui->comboBox_receiver->currentText();

    QString filePath = QFileDialog::getOpenFileName(
        this, ("Select an attachment"),
        QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation),
        ("File (*.json *.txt *.png *.jpg *.jpeg)"));

    if (filePath.isEmpty()) {
        QMessageBox::critical(this, "QTCPClient",
                              "You haven't selected any attachment!");
        return;
    }

    // 发送给所有客户端
    if (receiver == "Broadcast") {
        foreach (QTcpSocket* socket, connection_set) {
            sendAttachment(socket, filePath);
        }
    }
    // 发送给指定客户端
    else {
        foreach (QTcpSocket* socket, connection_set) {
            if (socket->socketDescriptor() == receiver.toLongLong()) {
                sendAttachment(socket, filePath);
                break;
            }
        }
    }
    ui->lineEdit_message->clear();
}

// 发送消息
void MainWindow::sendMessage(QTcpSocket* socket)
{
    if (socket) {
        if (socket->isOpen()) {
            QString str = ui->lineEdit_message->text();

            QDataStream socketStream(socket);
            socketStream.setVersion(QDataStream::Qt_5_15);

            QByteArray header;
            header.prepend(
                QString("fileType:message,fileName:null,fileSize:%1;")
                    .arg(str.size())
                    .toUtf8());
            header.resize(128);

            QByteArray byteArray = str.toUtf8();
            byteArray.prepend(header);

            socketStream << byteArray;
        }
        else
            QMessageBox::critical(this, "QTCPServer",
                                  "Socket doesn't seem to be opened");
    }
    else
        QMessageBox::critical(this, "QTCPServer", "Not connected");
}

// 发送文件
void MainWindow::sendAttachment(QTcpSocket* socket, QString filePath)
{
    if (socket) {
        if (socket->isOpen()) {
            QFile m_file(filePath);
            if (m_file.open(QIODevice::ReadOnly)) {
                QFileInfo fileInfo(m_file.fileName());
                QString   fileName(fileInfo.fileName());

                QDataStream socketStream(socket);
                socketStream.setVersion(QDataStream::Qt_5_15);

                QByteArray header;
                header.prepend(
                    QString("fileType:attachment,fileName:%1,fileSize:%2;")
                        .arg(fileName)
                        .arg(m_file.size())
                        .toUtf8());
                header.resize(128);

                QByteArray byteArray = m_file.readAll();
                byteArray.prepend(header);

                socketStream << byteArray;
            }
            else
                QMessageBox::critical(this, "QTCPClient",
                                      "Couldn't open the attachment!");
        }
        else
            QMessageBox::critical(this, "QTCPServer",
                                  "Socket doesn't seem to be opened");
    }
    else
        QMessageBox::critical(this, "QTCPServer", "Not connected");
}

// 消息展示
void MainWindow::displayMessage(const QString& str)
{
    ui->textBrowser_receivedMessages->append(str);
}

// 客户端断开后删除combobox中ip连接
void MainWindow::refreshComboBox()
{
    ui->comboBox_receiver->clear();
    ui->comboBox_receiver->addItem("Broadcast");
    foreach (QTcpSocket* socket, connection_set)
        ui->comboBox_receiver->addItem(
            QString::number(socket->socketDescriptor()));
}



TCP客户端
MainWindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
signals:
    void newMessage(QString);
private slots:
    void readSocket();
    void discardSocket();
    void displayError(QAbstractSocket::SocketError socketError);

    void displayMessage(const QString& str);
    void on_pushButton_sendMessage_clicked();
    void on_pushButton_sendAttachment_clicked();
private:
    Ui::MainWindow *ui;

    QTcpSocket* socket;
};

#endif // MAINWINDOW_H


MainWindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget* parent)
    : QMainWindow(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    socket = new QTcpSocket(this);

    connect(this, &MainWindow::newMessage, this,
            &MainWindow::displayMessage);  // 展示消息
    connect(socket, &QTcpSocket::readyRead, this,
            &MainWindow::readSocket);  // 建立连接，读取消息
    connect(socket, &QTcpSocket::disconnected, this,
            &MainWindow::discardSocket);  // 没有成功建立连接
    connect(socket, &QAbstractSocket::errorOccurred, this,
            &MainWindow::displayError);  // 错误异常

    socket->connectToHost(QHostAddress::LocalHost, 8080);

    if (socket->waitForConnected())
        ui->statusBar->showMessage("Connected to Server");
    else {
        QMessageBox::critical(this, "QTCPClient",
                              QString("The following error occurred: %1.")
                                  .arg(socket->errorString()));
        exit(EXIT_FAILURE);
    }
}

MainWindow::~MainWindow()
{
    if (socket->isOpen())
        socket->close();
    delete ui;
}

// 读取消息
void MainWindow::readSocket()
{
    QByteArray buffer;

    QDataStream socketStream(socket);
    socketStream.setVersion(QDataStream::Qt_5_15);

    socketStream.startTransaction();
    socketStream >> buffer;

    if (!socketStream.commitTransaction()) {
        QString message = QString("%1 :: Waiting for more data to come..")
                              .arg(socket->socketDescriptor());
        emit newMessage(message);
        return;
    }

    // mid
    // 从位置pos开始，从该字节数组返回一个包含len个字节的字节数组。
    // 如果len为-1（默认值），或者pos+ len> =size（），
    // 则返回一个字节数组，其中包含从位置pos到字节数组末尾的所有字节
    QString header   = buffer.mid(0, 128);
    QString fileType = header.split(",")[0].split(":")[1];

    buffer = buffer.mid(128);

    // 读取文件
    if (fileType == "attachment") {
        QString fileName = header.split(",")[1].split(":")[1];
        QString ext      = fileName.split(".")[1];
        QString size     = header.split(",")[2].split(":")[1].split(";")[0];

        if (QMessageBox::Yes ==
            QMessageBox::question(
                this, "QTCPServer",
                QString("You are receiving an attachment from sd:%1 of size: "
                        "%2 bytes, called %3. Do you want to accept it?")
                    .arg(socket->socketDescriptor())
                    .arg(size)
                    .arg(fileName))) {
            QString filePath = QFileDialog::getSaveFileName(
                this, tr("Save File"),
                QStandardPaths::writableLocation(
                    QStandardPaths::DocumentsLocation) +
                    "/" + fileName,
                QString("File (*.%1)").arg(ext));

            QFile file(filePath);
            if (file.open(QIODevice::WriteOnly)) {
                file.write(buffer);
                QString message =
                    QString("INFO :: Attachment from sd:%1 successfully stored "
                            "on disk under the path %2")
                        .arg(socket->socketDescriptor())
                        .arg(QString(filePath));
                emit newMessage(message);
            }
            else
                QMessageBox::critical(
                    this, "QTCPServer",
                    "An error occurred while trying to write the attachment.");
        }
        else {
            QString message = QString("INFO :: Attachment from sd:%1 discarded")
                                  .arg(socket->socketDescriptor());
            emit newMessage(message);
        }
    }
    // 读取消息
    else if (fileType == "message") {
        QString message =
            QString("%1 :: %2")
                .arg(socket->socketDescriptor())
                .arg(QString::fromStdString(buffer.toStdString()));
        emit newMessage(message);
    }
}

// 没有成功连接服务器
void MainWindow::discardSocket()
{
    socket->deleteLater();
    socket = nullptr;

    ui->statusBar->showMessage("Disconnected!");
}

// 错误异常
void MainWindow::displayError(QAbstractSocket::SocketError socketError)
{
    switch (socketError) {
        case QAbstractSocket::RemoteHostClosedError: break;
        case QAbstractSocket::HostNotFoundError:
            QMessageBox::information(this, "QTCPClient",
                                     "The host was not found. Please check the "
                                     "host name and port settings.");
            break;
        case QAbstractSocket::ConnectionRefusedError:
            QMessageBox::information(
                this, "QTCPClient",
                "The connection was refused by the peer. Make sure QTCPServer "
                "is running, and check that the host name and port settings "
                "are correct.");
            break;
        default:
            QMessageBox::information(
                this, "QTCPClient",
                QString("The following error occurred: %1.")
                    .arg(socket->errorString()));
            break;
    }
}

// 发送消息
void MainWindow::on_pushButton_sendMessage_clicked()
{
    if (socket) {
        if (socket->isOpen()) {
            QString str = ui->lineEdit_message->text();

            QDataStream socketStream(socket);
            socketStream.setVersion(QDataStream::Qt_5_15);

            QByteArray header;
            header.prepend(
                QString("fileType:message,fileName:null,fileSize:%1;")
                    .arg(str.size())
                    .toUtf8());
            header.resize(128);

            QByteArray byteArray = str.toUtf8();
            byteArray.prepend(header);

            socketStream << byteArray;

            ui->lineEdit_message->clear();
        }
        else
            QMessageBox::critical(this, "QTCPClient",
                                  "Socket doesn't seem to be opened");
    }
    else
        QMessageBox::critical(this, "QTCPClient", "Not connected");
}

// 发送文件
void MainWindow::on_pushButton_sendAttachment_clicked()
{
    if (socket) {
        if (socket->isOpen()) {
            QString filePath = QFileDialog::getOpenFileName(
                this, ("Select an attachment"),
                QStandardPaths::writableLocation(
                    QStandardPaths::DocumentsLocation),
                ("File (*.json *.txt *.png *.jpg *.jpeg)"));

            if (filePath.isEmpty()) {
                QMessageBox::critical(this, "QTCPClient",
                                      "You haven't selected any attachment!");
                return;
            }

            QFile m_file(filePath);
            if (m_file.open(QIODevice::ReadOnly)) {
                QFileInfo fileInfo(m_file.fileName());
                QString   fileName(fileInfo.fileName());

                QDataStream socketStream(socket);
                socketStream.setVersion(QDataStream::Qt_5_15);

                QByteArray header;
                // prepend 前置
                header.prepend(
                    QString("fileType:attachment,fileName:%1,fileSize:%2;")
                        .arg(fileName)
                        .arg(m_file.size())
                        .toUtf8());
                header.resize(128);

                QByteArray byteArray = m_file.readAll();
                byteArray.prepend(header);

                socketStream << byteArray;
            }
            else
                QMessageBox::critical(this, "QTCPClient",
                                      "Attachment is not readable!");
        }
        else
            QMessageBox::critical(this, "QTCPClient",
                                  "Socket doesn't seem to be opened");
    }
    else
        QMessageBox::critical(this, "QTCPClient", "Not connected");
}

// 展示消息
void MainWindow::displayMessage(const QString& str)
{
    ui->textBrowser_receivedMessages->append(str);
}



线程与进程
线程管理器
qtLearn11ProcessManager.h:
#pragma once
#pragma execution_character_set("utf-8")

#include "ui_qtLearn11ProcessManager.h"
#include 
#include 
#include 

class qtLearn11ProcessManager : public QMainWindow {
    Q_OBJECT

  public:
    qtLearn11ProcessManager(QWidget* parent = nullptr);
    ~qtLearn11ProcessManager();

  private:
    Ui::qtLearn11ProcessManagerClass ui;

    QTableView*         tableView;
    QStandardItemModel* model;
    QString             cPid;

  private slots:
    // QTableView 行事件
    void sendContent(QModelIndex);
    //点击删除事件
    void deletePro();
};


qtLearn11ProcessManager.cpp:
#include "qtLearn11ProcessManager.h"
#include "windows.h"   //1 顺序不可颠倒
#include "tlhelp32.h"  //2
#include 
#include 
#include 
#include 
#include 

qtLearn11ProcessManager::qtLearn11ProcessManager(QWidget* parent)
    : QMainWindow(parent)
{
    ui.setupUi(this);

    //实例 QListView
    tableView = new QTableView(this);
    // QListView 位置
    tableView->setGeometry(QRect(10, 10, 340, 430));
    //实例 QPushButton
    QPushButton* button = new QPushButton(this);
    button->setGeometry(QRect(500, 450, 80, 25));
    button->setText("结束进程");
    connect(button, SIGNAL(clicked()), this, SLOT(deletePro()));
    //实例数据模型
    model = new QStandardItemModel();
    model->setHorizontalHeaderItem(0, new QStandardItem("进程名"));
    model->setHorizontalHeaderItem(1, new QStandardItem("PID"));
    //获取系统快照句柄，可以获取进程、线程、模块、进程使用的堆的句柄
    HANDLE hProcessSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    if (hProcessSnap == FALSE) {
        qDebug() << "调用失败";
        return;
    }
    PROCESSENTRY32 pe32;
    pe32.dwSize = sizeof(PROCESSENTRY32);
    BOOL bRet   = Process32First(hProcessSnap, &pe32);
    int  i      = 0;
    while (bRet) {
        // i++;
        前面 2 行不要
        // if (i > 1) {
        //     //获取进程名
        //     QString pName = QString::fromWCharArray(pe32.szExeFile);
        //     //追加数据模型第一列
        //     model->setItem(i - 2, 0, new QStandardItem(pName));
        //     //获取 PID 号
        //     QString pid = QString::number(pe32.th32ProcessID);
        //     //追加数据模型第二列
        //     model->setItem(i - 2, 1, new QStandardItem(pid));
        // }

        //获取进程名
        QString pName = QString::fromWCharArray(pe32.szExeFile);
        //追加数据模型第一列
        model->setItem(i - 2, 0, new QStandardItem(pName));
        //获取 PID 号
        QString pid = QString::number(pe32.th32ProcessID);
        //追加数据模型第二列
        model->setItem(i - 2, 1, new QStandardItem(pid));

        bRet = Process32Next(hProcessSnap, &pe32);
        i++;
    }
    //清理 hProcessSnap
    ::CloseHandle(hProcessSnap);

    //绑定数据
    tableView->setModel(model);
    //列宽
    tableView->setColumnWidth(0, 190);
    tableView->setColumnWidth(1, 130);
    //选取整行
    tableView->setSelectionBehavior(QAbstractItemView::SelectRows);
    //不可修改
    tableView->setEditTriggers(QAbstractItemView::NoEditTriggers);
    //行单击事件
    connect(tableView, SIGNAL(clicked(QModelIndex)),
            SLOT(sendContent(QModelIndex)));
    //纵向头隐藏
    tableView->verticalHeader()->setVisible(false);
    //关闭滚动条
    // tableView->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    //隔行变色
    tableView->setAlternatingRowColors(true);
}

qtLearn11ProcessManager::~qtLearn11ProcessManager() {}

// QTableView 点击行事件
void qtLearn11ProcessManager::sendContent(QModelIndex)
{
    //获取点击行索引
    int index = tableView->currentIndex().row();
    //将 PID 值赋予 QString 类型保存
    cPid = model->data(model->index(index, 1)).toString();
}
//点击结束进程
void qtLearn11ProcessManager::deletePro()
{
    if (cPid == "") {
        QMessageBox::warning(this, "警告", tr("请选择要结束的进程!!!"));
    }
    else {
        // Taskkill/pid 3184
        //结束进程命令
        QProcess    process(0);
        QString     dos = "Taskkill";
        QStringList list;
        list.append("/pid");
        list.append(cPid);
        //拼接参数，因为 QProcess 不支持中文与空格
        process.start(dos, list);
        QMessageBox::warning(this, "警告", tr("成功结束!!!"));
    }
}


线程 QThread 应用
qtLearn11QThread.h：
#pragma once
#pragma execution_character_set("utf-8")

#include "ui_qtLearn11QThread.h"
#include 
#include 
#include 

class qtLearn11QThread : public QMainWindow {
    Q_OBJECT

  public:
    qtLearn11QThread(QWidget* parent = nullptr);
    ~qtLearn11QThread();

  private:
    Ui::qtLearn11QThreadClass ui;
    QPushButton*              starThread;
    QThread*                  thread;

  private slots:
    //执行线程
    void startFun();
};


qtLearn11QThread.cpp：
#include "qtLearn11QThread.h"
#include 

qtLearn11QThread::qtLearn11QThread(QWidget* parent) : QMainWindow(parent)
{
    ui.setupUi(this);

    //执行线程 1
    starThread = new QPushButton(this);
    starThread->setText("执行线程 1");
    starThread->setGeometry(QRect(30, 50, 100, 25));
    connect(starThread, SIGNAL(clicked()), this, SLOT(startFun()));
}

qtLearn11QThread::~qtLearn11QThread() {}

void qtLearn11QThread::startFun()
{
    //实例线程
    thread = new QThread();
    //启动
    thread->start();
    int i = 0;
    while (true) {
        //挂起 1 秒
        thread->sleep(1);
        i++;
        qDebug() << i;
        if (i > 2) {
            break;
        }
    }
    qDebug() << "结束";
}



线程 QRunnable 应用
runnable.h:
#include 
#include 
class runnable : public QRunnable {
  public:
    runnable(QProgressBar* progressBar);
    virtual ~runnable();
    void run();

  private:
    QProgressBar* m_ProgressBar;
};


runnable.cpp:
#include "runnable.h"
#include 
runnable::runnable(QProgressBar* progressBar)
    : QRunnable(), m_ProgressBar(progressBar)
{
    for (int i = 0; i < 100000; i++) {
        progressBar->setValue(i);
    }
}
runnable::~runnable() {}

void runnable::run(){}

qtLearn11QRunnable.h:
#pragma once
#pragma execution_character_set("utf-8")

#include "ui_qtLearn11QRunnable.h"
#include 
#include 
#include 

class qtLearn11QRunnable : public QMainWindow {
    Q_OBJECT

  public:
    qtLearn11QRunnable(QWidget* parent = nullptr);
    ~qtLearn11QRunnable();

  private:
    Ui::qtLearn11QRunnableClass ui;

    QPushButton*  startButton;
    QProgressBar* progressBar;
    QProgressBar* progressBar2;
  private slots:
    void startFun();
};


qtLearn11QRunnable.cpp:
#include "qtLearn11QRunnable.h"
#include "runnable.h"
#include 
#include 

qtLearn11QRunnable::qtLearn11QRunnable(QWidget* parent) : QMainWindow(parent)
{
    ui.setupUi(this);

    //第一个 QProgressBar
    progressBar = new QProgressBar(this);
    progressBar->setGeometry(QRect(50, 50, 200, 16));
    //初始值
    progressBar->setValue(0);
    //范围值
    progressBar->setRange(0, 100000 - 1);
    //第二个 QProgressBar
    progressBar2 = new QProgressBar(this);
    progressBar2->setGeometry(QRect(50, 100, 200, 16));
    //初始值
    progressBar2->setValue(0);
    //范围值
    progressBar2->setRange(0, 100000 - 1);
    //实例按钮
    startButton = new QPushButton(this);
    startButton->setGeometry(QRect(260, 45, 80, 25));
    startButton->setText("执行");
    connect(startButton, SIGNAL(clicked()), this, SLOT(startFun()));
}

qtLearn11QRunnable::~qtLearn11QRunnable() {}

//开始执行
void qtLearn11QRunnable::startFun()
{
    //实例 runnable 类
    runnable* hInst = new runnable(progressBar);
    //实例第二个
    hInst = new runnable(progressBar2);
    //进程池
    QThreadPool::globalInstance()->start(hInst);
}