QMouseEvent下可以被重寫的虛函數:
1.void mousePressEvent(QMouseEvent *event); //鼠標鍵被按下的事件.
2.void mouseReleaseEvent(QMouseEvent *event); //鼠標鍵被放開的事件.
3.void mouseMoveEvent(QMouseEvent *event); //按住鼠標鍵移動的事件.
4.void mouseDoubleClickEvent(QMouseEvent *event); //鼠標鍵被雙擊的事件.
QMouseEvent類中的重要函數:
1.QPoint pos(); //返回鼠標相對於父部件的座標.
2.QPoint globalPos(); //返回鼠標的全局座標.
3.QMouseButton button(); //返回鼠標被點擊的鍵.
“c.cpp”下的代碼:
#include "c.h"c::c(QWidget *parent)
: QMainWindow(parent)
{
ui.setupUi(this);
}
c::~c()
{
}void c::mouseMoveEvent(QMouseEvent *event)
{ //保存鼠標移動的時候的尾座標.
end = event->pos(); //用來重繪更新.可以理解爲調用paintEvent函數，但不一定是立即調用的.在此程序中可以理解爲:馬上更新窗口上顯示的圖像.
update();
}void c::paintEvent(QPaintEvent *event)
{ //畫一個矩形.
QPainter painter(this);
painter.setPen(Qt::red);
QRect temp(start, end);
painter.setBrush(Qt::green);
painter.drawRect(temp);
}void c::mouseReleaseEvent(QMouseEvent *event)
{ //當左鍵釋放後，保存尾座標.
if (event->button() == Qt::LeftButton)
{ this->end = event->pos();
update();
}
}void c::mousePressEvent(QMouseEvent *event)
{ //當左鍵被按下時，保存首座標.並更新重繪.
if (event->button() == Qt::LeftButton)
{ //點擊的時候定下初始位置.
this->start = event->pos();
}
}123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051“c.h”的代碼:
#ifndef C_H#define C_H#include <QtWidgets/QMainWindow>#include "ui_c.h"#include <QPixmap>#include <QMouseEvent>#include <QMessageBox>#include <QPainter>#include <QPaintEvent>#include <QVector>class c : public QMainWindow
{
Q_OBJECTpublic: c(QWidget *parent = 0);
~c();protected: void mouseMoveEvent(QMouseEvent *event); void mouseReleaseEvent(QMouseEvent *event); void mousePressEvent(QMouseEvent *event); void paintEvent(QPaintEvent *event);private:
Ui::cClass ui;
QPoint start;
QPoint end;
};#endif // C_H1234567891011121314151617181920212223242526272829303132最後是”main.cpp”下的代碼:
#include "c.h"#include <QtWidgets/QApplication>int main(int argc, char *argv[])
{
QApplication a(argc, argv);
c w;
w.show(); return a.exec();
}