#ifndef MYBUTTON_H#define MYBUTTON_H#include 
     
      class MyButton : public QPushButton{    Q_OBJECTpublic:    explicit MyButton(QWidget *parent = nullptr);protected:    void mousePressEvent(QMouseEvent *e);signals:public slots:};#endif // MYBUTTON_H
     

#include "mybutton.h"#include 
     
      #include 
      
       MyButton::MyButton(QWidget *parent) : QPushButton(parent){}void MyButton::mousePressEvent(QMouseEvent *e){    if(e->button() == Qt::LeftButton)    {        qDebug()<<"left mousebutton";        e->ignore();    }    else    {        QPushButton::mousePressEvent(e);    }}
      
     

#ifndef MYLABEL_H#define MYLABEL_H#include 
     
      class mylabel : public QLabel{    Q_OBJECTpublic:    explicit mylabel(QWidget *parent = nullptr);protected:    void mousePressEvent(QMouseEvent *ev);    void mouseReleaseEvent(QMouseEvent *ev);    void mouseMoveEvent(QMouseEvent *ev);    void enterEvent(QEvent *);    void leaveEvent(QEvent *);signals:public slots:};#endif // MYLABEL_H
     

#include "mylabel.h"#include 
     
      #include 
      
       mylabel::mylabel(QWidget *parent) : QLabel(parent){    this->setMouseTracking(true);}void mylabel::mousePressEvent(QMouseEvent *ev){    int i = ev -> x();    int j = ev -> y();//    QString str = QString("abc %1 ^_^ %2").arg(123).arg("hello");    if (ev->button() == Qt::LeftButton)    {    }else if(ev->button() == Qt::RightButton)    {    }else if(ev->button() == Qt::MiddleButton)    {    }    QString text = QString("
       
        
Mouse Press: (%1, %2)
       ")            .arg(i).arg(j);    this->setText(text);}void mylabel::mouseReleaseEvent(QMouseEvent *ev){    QString text = QString("
       
        
Mouse Release: (%1, %2)
       ")            .arg(ev -> x()).arg(ev -> y());    this->setText(text);}void mylabel::mouseMoveEvent(QMouseEvent *ev){    QString text = QString("
       
        
Mouse Move: (%1, %2)
       ")            .arg(ev -> x()).arg(ev -> y());    //this->setText(text);}void mylabel::enterEvent(QEvent *e){    QString text = QString("
       
        
Mouse enter
       ");    this->setText(text);}void mylabel::leaveEvent(QEvent *e){    QString text = QString("
       
        
Mouse leave
       ");    this->setText(text);}
      
     

#ifndef MYWIDGET_H#define MYWIDGET_H#include 
     
      namespace Ui {class MyWidget;}class MyWidget : public QWidget{    Q_OBJECTpublic:    explicit MyWidget(QWidget *parent = 0);    ~MyWidget();protected:    void keyPressEvent(QKeyEvent *event);    void timerEvent(QTimerEvent *event);    void closeEvent(QCloseEvent *event);    bool eventFilter(QObject *watched, QEvent *event);private:    Ui::MyWidget *ui;    int timerId;    int timerId2;};#endif // MYWIDGET_H
     

#include "mywidget.h"#include "ui_mywidget.h"#include 
     
      #include 
      
       #include 
       
        MyWidget::MyWidget(QWidget *parent) :    QWidget(parent),    ui(new Ui::MyWidget){    ui->setupUi(this);    timerId = this->startTimer(1000);    timerId2 = this->startTimer(500);    connect(ui->pushButton,&MyButton::clicked,            [=]()    {        qDebug()<<"press now";    });    ui->label_2->installEventFilter(this);}void MyWidget::keyPressEvent(QKeyEvent *event){    qDebug()<<(char)(event->key());    if (event->key() == Qt::Key_A)    {        qDebug()<<"Qt::Key_A";    }}void MyWidget::timerEvent(QTimerEvent *event){    if(event->timerId() == this->timerId)    {        static int sec = 0;        ui->label->setText(QString("
        
         
Timer: (%1)
        ")                           .arg(sec++));        if(5==sec)        {            this->killTimer(timerId);        }    }    else if(event->timerId() == this->timerId2)    {        static int sec = 0;        ui->label_2->setText(QString("
        
         
Timer: (%1)
        ")                           .arg(sec++));    }}void MyWidget::closeEvent(QCloseEvent *event){    int ret = QMessageBox::question(this,"question","close it?");    if (ret == QMessageBox::Yes)    {        event->accept();    }    else    {        event->ignore();    }}bool MyWidget::eventFilter(QObject *watched, QEvent *event){    if(watched == ui->label_2)    {        QMouseEvent *env = static_cast
        
         (event);        if(event->type() == QEvent::MouseMove)        {            ui->label_2->setText(QString("Mouse move:(%1, %2)").arg(env->x()).arg(env->y()));            return true;        }    }    else    {        return QWidget::eventFilter(watched,event);    }}MyWidget::~MyWidget(){    delete ui;}
        
       
      
     

#include "mywidget.h"#include 
     
      int main(int argc, char *argv[]){    QApplication a(argc, argv);    MyWidget w;    w.show();    return a.exec();}