QT用户登录注册，数据库实现

登录窗口头文件

#ifndef LOGINUI_H
#define LOGINUI_H

#include 
#include 
#include 
#include 
#include 

#include  //数据库管理类
#include     //执行sql语句的类
#include    //数据库记录类

#include 

#include "client.h"

class LoginUI : public QWidget
{
    Q_OBJECT

private:
    //标签类组件
    QLabel* Background_Lab;
    QLabel* Titile_Lab;
    QLabel* Username_Lab;
    QLabel* Password_Lab;

    //按钮类组件
    QPushButton* Close_Btn;
    QPushButton* Hide_Btn;
    QPushButton* Login_Btn;
    QPushButton* Register_Btn;

    //行编辑器类组件
    QLineEdit* Username_Edit;
    QLineEdit* Password_Edit;

    //声明数据库对象
    QSqlDatabase db;

    //UI绘制函数
    bool DrawLoginUI();

    //构造函数
    LoginUI();
    bool construct();

private slots:
    //槽函数
    void On_CloseBtn_Clicked();
    void On_Loginbtn_Slots();
    void On_Registerbtn_Slots();


public:
    //实例化对象
    static LoginUI* NewInstance();
    void show();
    ~LoginUI();

signals:
    void jump();



};
#endif //LOGINUI_H

登录窗口函数实现

#include "LoginUI.h"
#include 


bool LoginUI::DrawLoginUI()
{
    bool ret = true;

    //背景色设置
    Background_Lab = new QLabel(this);

    if( Background_Lab != nullptr)
    {
        Background_Lab->resize(538, 160);
        Background_Lab->setStyleSheet("background-color:rgb(115,70,240)");
    }
    else
    {
        ret = false;
    }

    //窗口标识
    Titile_Lab = new QLabel(this);

    if( Titile_Lab != nullptr )
    {
        Titile_Lab->resize(90, 50);
        Titile_Lab->setPixmap(QPixmap(":/QT_Icon/QQ_Icon.png"));
        Titile_Lab->setScaledContents(true);
    }
    else
    {
        ret = false;
    }

    //关闭按键
    Close_Btn = new QPushButton(this);

    if( Close_Btn != nullptr )
    {
        Close_Btn->resize(20, 20);
        Close_Btn->setIcon(QIcon(":/QT_Icon/close02.png"));
        Close_Btn->move(508, 10);
        connect(this->Close_Btn, &QPushButton::clicked, this, &LoginUI::On_CloseBtn_Clicked);
    }
    else
    {
        ret = false;
    }

    //隐藏按键
    Hide_Btn = new QPushButton(this);

    if( Hide_Btn != nullptr )
    {
        Hide_Btn->resize(20, 20);
        Hide_Btn->setIcon(QIcon(":/QT_Icon/hide02.png"));
        Hide_Btn->move(468, 10);
        connect(this->Hide_Btn, &QPushButton::clicked, this, &LoginUI::hide);
    }
    else
    {
        ret = false;
    }

    //用户名输入栏
    Username_Edit = new QLineEdit(this);

    if( Username_Edit != nullptr )
    {
        Username_Edit->resize(260, 40);
        Username_Edit->move(159, 173);
        Username_Edit->setMaxLength(16);
        Username_Edit->setPlaceholderText("QQ账号/手机号/邮箱");
    }
    else
    {
        ret = false;
    }

    //密码输入栏
    Password_Edit = new QLineEdit(this);

    if( Password_Edit != nullptr )
    {
        Password_Edit->resize(260, 40);
        Password_Edit->move(Username_Edit->x(), Username_Edit->y()+60);
        Password_Edit->setEchoMode(QLineEdit::Password);
        Password_Edit->setMaxLength(16);
    }
    else
    {
        ret = false;
    }

    //用户名输入栏标签
    Username_Lab = new QLabel(this);

    if( Username_Lab != nullptr )
    {
        Username_Lab->resize(30, 30);
        Username_Lab->move(Username_Edit->x()-40, Username_Edit->y()+5);
        Username_Lab->setPixmap(QPixmap(":/QT_Icon/windos_icon1.png"));
        Username_Lab->setScaledContents(true);
    }
    else
    {
        ret = false;
    }

    //密码输入栏标签
    Password_Lab = new QLabel(this);

    if( Password_Lab != nullptr )
    {
        Password_Lab->resize(30, 30);
        Password_Lab->move(Password_Edit->x()-40, Password_Edit->y()+5);
        Password_Lab->setPixmap(QPixmap(":/QT_Icon/password.png"));
        Password_Lab->setScaledContents(true);
    }
    else
    {
        ret = false;
    }

    //登录按键
    Login_Btn = new QPushButton("登录",this);

    if( Login_Btn != nullptr )
    {
        Login_Btn->resize(130, 40);
        Login_Btn->setStyleSheet("background-color:rgb(8,189,253);");
        Login_Btn->move(Password_Lab->x(), Password_Lab->y()+60);
        connect(this->Login_Btn, &QPushButton::clicked, this, &LoginUI::On_Loginbtn_Slots);
    }
    else
    {
        ret = false;
    }

    //注册按键
    Register_Btn = new QPushButton("注册",this);

    if( Register_Btn != nullptr )
    {
        Register_Btn->resize(130, 40);
        Register_Btn->setStyleSheet("background-color:rgb(8,189,253);");
        Register_Btn->move(Login_Btn->x()+170, Login_Btn->y());
        connect(this->Register_Btn, &QPushButton::clicked, this, &LoginUI::On_Registerbtn_Slots);
    }
    else
    {
        ret = false;
    }

    return ret;
}

LoginUI::LoginUI(): QWidget(nullptr, Qt::WindowCloseButtonHint)
{
}



void LoginUI::show()
{
    setWindowFlag(Qt::FramelessWindowHint);

    setFixedSize(538, 373);

    QWidget::show();
}


LoginUI::~LoginUI()
{
}

//构造函数
bool LoginUI::construct()
{

    //UI界面绘制
    bool ret = true;

    ret = DrawLoginUI();


    //数据库创建
    //判断自己的数据库对象中，是否包含要处理的数据库，没有则添加一个数据库
    if( !db.contains("UserMsg.db"))
    {
        //添加一个数据库，调用该类中的静态成员函数addDatabase()
        db = QSqlDatabase::addDatabase("QSQLITE");//使用sqlite3数据库

        //设置数据库名字
        db.setDatabaseName("UserMsg.db");
    }

    //此时数据库已经创建完成
    //打开数据库
    if( !db.open() )
    {
        QMessageBox::information(this, "提示", "数据库打开失败");
        ret = false;
    }

    //使用sql语句进行创建表的操作
    //准备sql语句
    QString Create_Table_Sql = "create table if not exists user_msg("
                               "user_name varchar(16) primary key,"
                               "password varchar(16))";


    //准备语句执行者
    QSqlQuery querry;

    //执行sql语句
    if( !querry.exec(Create_Table_Sql) )
    {
        QMessageBox::information(this, "提示", "创建表失败");
        ret = false;
    }

    return ret;

}

//关闭按键槽函数
void LoginUI::On_CloseBtn_Clicked()
{
    QMessageBox box(QMessageBox::Question, "关闭", "您确定要退出？", QMessageBox::Yes | QMessageBox::No, this);
    box.setDefaultButton(QMessageBox::No);

    int ret = box.exec();

    if(ret == QMessageBox::Yes)
    {
        this->close();
    }
    else if(ret == QMessageBox::No)
    {

    }
}

//登录按键槽函数
void LoginUI::On_Loginbtn_Slots()
{
    //获取ui界面的用户信息
    QString name = Username_Edit->text();
    QString password = Password_Edit->text();

    if( name.isEmpty() )
    {
        QMessageBox::information(this, "提示", "请输入用户名");
        return;
    }
    else if( password.isEmpty() )
    {
        QMessageBox::information(this, "提示", "请输入密码");
        return;
    }

    //准备sql查询语句
    QString sql = QString("select * from user_msg where user_name = '%1' and password = '%2'").arg(name).arg(password);

    //准备语句执行者
    QSqlQuery querry;
    querry.exec(sql);

//    qDebug() <

//    qDebug() << querry.value(0);
//    qDebug() << querry.value(1);

    //执行sql语句
    if( !querry.next() )
    {
        QMessageBox::information(this, "提示", "账号密码错误");
        return;
    }
    else
    {

        QMessageBox::information(this, "提示", "登陆成功");
        emit jump();
        this->close();

    }

}

//注册事件槽函数
void LoginUI::On_Registerbtn_Slots()
{
    //获取ui界面的用户信息
    QString name = Username_Edit->text();
    QString password = Password_Edit->text();

    //确保用户信息输入完整
    if( name.isEmpty() || password.isEmpty() )
    {
        QMessageBox::information(this, "提示", "请将信息填写完整");
        return;
    }

    //准备sql语句
    QString sql = QString("insert into user_msg(user_name, password) "
                          "values('%1', '%2')").arg(name).arg(password);

    //准备语句执行者
    QSqlQuery querry;
    if( !querry.exec(sql) )
    {
        QMessageBox::information(this, "提示", "注册失败");
        return;
    }
    else
    {
        QMessageBox::information(this, "提示", "注册成功");
    }
}


//创建一个新对象
LoginUI *LoginUI::NewInstance()
{
    LoginUI* ret = new LoginUI;

    if( !ret->construct() || ret == nullptr )
    {
        delete ret;

        ret = nullptr;
    }


    return ret;
}