QT学习笔记（6）事件

Qt的事件不同于信号槽机制，更加的灵活

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

class EventLabel : public QLabel
{
protected:
    void mouseMoveEvent(QMouseEvent*);
    void mousePressEvent(QMouseEvent*);
    void mouseReleaseEvent(QMouseEvent*);
};

void EventLabel :: mouseMoveEvent(QMouseEvent* event)
{
    this -> setText(QString("
Move: (%1,%2)<\h1><\center>"). //arg替换占位符
                    arg(QString::number(event->x()),QString::number(event->y())));
}

void EventLabel :: mousePressEvent(QMouseEvent* event)
{
    this -> setText(QString("
Press:(%1,%2)<\h1>\center>").arg(QString::number(event->x()), QString::number(event->y())));
}

void EventLabel :: mouseReleaseEvent(QMouseEvent* event)
{
    QString msg;
    msg.sprintf("
Release: (%d, %d)",event->x(), event->y());
    this->setText(msg);
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    EventLabel *label = new EventLabel;
    label -> setWindowTitle("MouseEvent");
    label -> resize(300, 300);
    label -> setMouseTracking(true);
    label -> show();
    return a.exec();
}