QMouseEvent类表示一个鼠标事件，窗口中的按下，移动都会产生鼠标事件。
QWheelEvent用来表示滚轮事件，获取滚轮的移动方向和距离。
本案例效果：在文本框与框外鼠标样式改变，双击全屏，右击样式改变滑轮缩放文本框内内容。
.h
#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACEclass Widget : public QWidget
{Q_OBJECTpublic:Widget(QWidget *parent = nullptr);~Widget();private:Ui::Widget *ui;QPoint offset;
protected:void mouseMoveEvent(QMouseEvent *event) ;void mouseReleaseEvent(QMouseEvent *event) ;void mouseDoubleClickEvent(QMouseEvent *event) ;void mousePressEvent(QMouseEvent *event);void wheelEvent(QWheelEvent *event );
};
#endif // WIDGET_H
.cpp
#include "widget.h"
#include "ui_widget.h"
#include<QMouseEvent>Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);QCursor cursor;//创建光标cursor.setShape(Qt::OpenHandCursor);//设置光标样式setCursor(cursor);//使用光标
}Widget::~Widget()
{delete ui;
}void Widget::mousePressEvent(QMouseEvent *event)
{if(event->button() == Qt::LeftButton){QCursor cursor;cursor.setShape(Qt::ClosedHandCursor);QApplication::setOverrideCursor(cursor); //左键按下，改变样式offset = event->globalPos() - pos();}else if(event->button() == Qt::RightButton){//右键按下，显示图片QCursor cursor(QPixmap("../mymouseevent/dddd.png"));QApplication::setOverrideCursor(cursor);}
}void Widget::mouseMoveEvent(QMouseEvent *event)
{if(event->buttons() & Qt::LeftButton){ //注意！！！！必须为buttons,不是button，否则拖拽无效QPoint temp;temp = event->globalPos() - offset;move(temp);//根据差值移动位置}
}void Widget::mouseReleaseEvent(QMouseEvent *event)
{Q_UNUSED(event)//此处无用，避免警告QApplication::restoreOverrideCursor();//回复鼠标指针
}void Widget::mouseDoubleClickEvent(QMouseEvent *event)
{if(event->button() == Qt::LeftButton){ //鼠标左键按下if(windowState() != Qt::WindowFullScreen)//如果不是全屏setWindowState(Qt::WindowFullScreen);//窗口设置为全屏else setWindowState(Qt::WindowNoState);//恢复之前大小}
}void Widget::wheelEvent(QWheelEvent *event)
{if(event->delta() > 0){ui->textEdit->zoomIn(); //放大}else{ui->textEdit->zoomOut(); //缩小}
}