第一種方法

效果圖

主要程式碼

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

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->label->installEventFilter(this);//安裝事件過濾器
}

MainWindow::~MainWindow()
{
    delete ui;
}

bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
    if (obj == ui->label)//指定某個QLabel
    {
        if (event->type() == QEvent::MouseButtonPress)//mouse button pressed
        {
            QMouseEvent *mouseEvent = static_cast<QMouseEvent*>(event);
            if(mouseEvent->button() == Qt::LeftButton)
            {
                QMessageBox::information(NULL,"點選","點選了我",
                                         QMessageBox::Yes|QMessageBox::No,QMessageBox::Yes);
                return true;
            }
            else
            {
                return false;
            }
        }
        else
        {
            return false;
        }
    }
    else
    {
        // pass the event on to the parent class
        return QMainWindow::eventFilter(obj, event);
    }
}
 

第二種方法

使用繼承QLabel，重寫事件處理的回撥函式mousePressEvent

效果圖

主要程式碼

#include "mylabel.h"

MyLabel::MyLabel(const QString & text,QWidget *parent) : QLabel(parent)
{
    setText(text);
}

MyLabel::MyLabel(QWidget *parent) : QLabel(parent)
{

}

void MyLabel::mousePressEvent(QMouseEvent *event)
{
    //Qt::LeftButton
    //Qt::RightButton
    if(event->button()== Qt::LeftButton)
    {
        QMessageBox::information(NULL,"單擊","單擊了我",
                                 QMessageBox::Yes|QMessageBox::No,QMessageBox::Yes);
    }
}
 

重寫 event()函式

主要程式碼

#include "mylabel.h"

MyLabel::MyLabel(const QString & text,QWidget *parent) : QLabel(parent)
{
    setText(text);
}

MyLabel::MyLabel(QWidget *parent) : QLabel(parent)
{

}

bool MyLabel::event(QEvent *e)
{
    if (e->type() == QEvent::MouseButtonPress)
    {
        QMouseEvent *mouseEvent = static_cast<QMouseEvent*>(e);
        if(mouseEvent->button() == Qt::LeftButton)
        {
            QMessageBox::information(NULL,"單擊","單擊了我",
                                     QMessageBox::Yes|QMessageBox::No,QMessageBox::Yes);
            return true;
        }
    }
    return QLabel::event(e);
}