QT之事件机制

Posted 2020-12-16 sunshine-gzw

MyPushButton.h:

#ifndef MYPUSHBUTTON_H
#define MYPUSHBUTTON_H
#include<QPushButton>
#include<QEvent>
#include<QMouseEvent>
class MyPushButton : public QPushButton
{
public:
    MyPushButton();
     MyPushButton(const QString& text,QWidget *parent=nullptr);
     bool event(QEvent *e);
     void mousePressEvent(QMouseEvent *e);
};

#endif // MYPUSHBUTTON_H

MyPushButton.cpp:

#include "MyPushButton.h"
#include<QWidget>
#include<QDebug>
MyPushButton::MyPushButton(const QString& text,QWidget *parent)
    :QPushButton(text,parent)
{
}
bool  MyPushButton::event(QEvent *e)
{
    if(e->type()==QEvent::MouseButtonPress)
    {
        QMouseEvent *x=static_cast<QMouseEvent*>(e);
       mousePressEvent(x);
       //e->ignore();
       //e->accept();
        return false; //表示我不处理这个事件
        //return true; //表示我处理了这个事件
    }
    return QWidget::event(e);
}
void MyPushButton::mousePressEvent(QMouseEvent *e)
{

    qDebug()<<"子类的事件执行"<<endl;
}

MyPushButton::MyPushButton()
{

}

Widget.h:

#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include "MyPushButton.h"
class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = 0);
    ~Widget();
    bool event(QEvent *e);
    void mousePressEvent(QMouseEvent *e);
private:
    MyPushButton *mypushbutton;
};

#endif // WIDGET_H

Widget.cpp:

#include "widget.h"
#include<QDebug>
Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    mypushbutton=new MyPushButton("按钮",this);
}

bool Widget::event(QEvent *e)
{
    return QWidget::event(e);
}

void Widget::mousePressEvent(QMouseEvent *e)
{
  qDebug()<<"父类的事件执行"<<endl;
}



Widget::~Widget()
{

}

main.cpp:

#include "widget.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}

效果: