Qt-控件重写

双击LineEdit控件执行一个事件。我们LineEdit正常是单击光标悬浮的这种状态，所以我需要对这个控件进行重写。

因为是要重写，所以我们需要自定义QLineEdit。

Qt 控件重写
/*MyLineEdit.h*/
#ifndef MYLINEEDIT_H
#define MYLINEEDIT_H

#include
#include
 
class MyLineEdit : public QLineEdit
{
    Q_OBJECT

public:
    explicit MyLineEdit(QWidget *parent = 0);
    ~MyLineEdit();
protected:
    void mouseDoubleClickEvent(QMouseEvent *event);
};

#endif    // MYLINEEDIT_H

把你要让这个控件执行的事件放到你重写的这个类中，并实现它。

/*MyLineEdit.cpp*/
#include "mylineedit.h"
#include
#include

MyLineEdit::MyLineEdit(QWidget *parent) :
    QLineEdit(parent)
{

}

MyLineEdit::~MyLineEdit()
{

}

void MyLineEdit::mouseDoubleClickEvent(QMouseEvent *event)
{
    qDebug()<<"hi~我在执行QLineEdit双击事件~";
}

做完这步就相当于重写完成了，接下来就是需要使用这个自定义的类。

/*from.h*/
#ifndef FORM_H
#define FORM_H

#include

namespace Ui {
class Form;
}

class Form : public QWidget
{
    Q_OBJECT

public:
    explicit Form(QWidget *parent = 0);
    ~Form();

private:
    Ui::Form *ui;
};

#endif // FORM_H

form.cpp
#include "form.h"
#include "ui_form.h"
#include "mylineedit.h"
Form::Form(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Form)
{
    ui->setupUi(this);
    MyLineEdit* a = new MyLineEdit(this);
    ui->verticalLayout->addWidget(a);
}

Form::~Form()
{
    delete ui;
}

/*********************重写QLineEdit的focusInEvent()和focusOutEvent()函数：

源码如下：

// MYLINEEDIT_H
#ifndef MYLINEEDIT_H
#define MYLINEEDIT_H
#include
class MyLineEdit : public QLineEdit
{
        Q_OBJECT

 public:
       MyLineEdit(QWidget *parent=0);
       ~MyLineEdit();
 protected:
       virtual void focusInEvent(QFocusEvent *e);
       virtual void focusOutEvent(QFocusEvent *e);
};
#endif // MYLINEEDIT_H
`

//myLineEdit.cpp
#include "myLineEdit.h"

MyLineEdit::MyLineEdit(QWidget *parent):QLineEdit(parent)
{

}

MyLineEdit::~MyLineEdit()
{

}

void MyLineEdit::focusInEvent(QFocusEvent *e)
{
       QPalette p=QPalette();
       p.setColor(QPalette::Base,Qt::green);    //QPalette::Base 对可编辑输入框有效，还有其他类型，具体的查看文档
       setPalette(p);
}

void MyLineEdit::focusOutEvent(QFocusEvent *e)
{
       QPalette p1=QPalette();
       p1.setColor(QPalette::Base,Qt::white);
       setPalette(p1);
}
`

//widget.cpp
#include "widget.h"
#include "ui_widget.h"
#include "MyLineEdit.h"
#include
#include
Widget::Widget(QWidget *parent) :
               QWidget(parent),
               ui(new Ui::Widget)
{
       ui->setupUi(this);
       init();
}
Widget::~Widget()
{
       delete ui;
}
void Widget::init()
{
       lineEdit1=new MyLineEdit(this);
       lineEdit2=new MyLineEdit(this);
       gridLayout=new QGridLayout;
       gridLayout->addWidget(lineEdit1,0,0);
       gridLayout->addWidget(lineEdit2,1,0);
       setLayout(gridLayout);
}