QT之鼠标和键盘事件重写

有时候我们需要重写键盘和鼠标的事件的处理函数，那么这个时候我们就需要进行事件编程

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QMouseEvent>
#include <QWheelEvent>
#include <QKeyEvent>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
protected:
    //我们来重写QT的5个标准的鼠标事件函数，从而实现我们自己想要的动作
    void mouseDoubleClickEvent(QMouseEvent *event);//鼠标双击事件
    void mouseMoveEvent(QMouseEvent *event);//数据表移动事件
    void mousePressEvent(QMouseEvent *event);//鼠标按下事件
    void mouseReleaseEvent(QMouseEvent *event);//鼠标松开事件
    void wheelEvent(QWheelEvent *event);    //鼠标滚轮事件

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

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

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

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

MainWindow::~MainWindow()
{
    delete ui;
}
void MainWindow::mouseDoubleClickEvent(QMouseEvent *event)
{
    if(event->button() == Qt::LeftButton){
        ui->label->setText("left button dbclicked");
    }
    else {
        ui->label->setText("right button dbclicked");
    }
}
void MainWindow::mouseMoveEvent(QMouseEvent *event)
{
    QPoint pos = event->globalPos();
    ui->label_2->setText(QString("(%1,%2)").arg(pos.rx()).arg(pos.ry()));
}
void MainWindow::mousePressEvent(QMouseEvent *event)
{
    if(event->button() == Qt::LeftButton){
        ui->label->setText("left button pressed");
    }
    else {
        ui->label->setText("right button pressed");
    }
}
void MainWindow::mouseReleaseEvent(QMouseEvent *event)
{
    if(event->button() == Qt::LeftButton){
        ui->label->setText("left button released");
    }
    else {
        ui->label->setText("right button released");
    }
}
void MainWindow::wheelEvent(QWheelEvent *event)
{
    if(event->delta() > 0){
        ui->label_2->setText("wheel up");
    }
    else {
        ui->label_2->setText("wheel down");
    }
}

void MainWindow::keyPressEvent(QKeyEvent *event)
{
    if(event->key() == Qt::Key_0)//键盘0按下
    {
        ui->label_2->setText("key 0 pressed");
    }
    if(event->key() == Qt::Key_1)
    {
        ui->label_2->setText("key 1 pressed");
    }
}

我们来看一下运行效果