只要關(guān)注一點(diǎn)：

滾輪事件里面有一個QWheelEvent

當(dāng)他的y值大于0的時候，說明是往前滾；

y小于0說明是往后滾

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程序運(yùn)行截圖如下：

源碼如下：

widget.h

#ifndef WIDGET_H #define WIDGET_H#include <QWidget>namespace Ui { class Widget; }class Widget : public QWidget {Q_OBJECTpublic:explicit Widget(QWidget *parent = 0);~Widget();protected:void wheelEvent(QWheelEvent *event) Q_DECL_OVERRIDE;void extendWindowsSize();void shrinkWindowsSize();private:Ui::Widget *ui;int m_originalWidth;int m_originalHeight; };#endif // WIDGET_H

widget.cpp

#include "widget.h" #include "ui_widget.h" #include <QPoint> #include <QWheelEvent>Widget::Widget(QWidget *parent) :QWidget(parent),ui(new Ui::Widget) {ui->setupUi(this);this->setWindowTitle("CSDN IT1995");m_originalWidth = this->width();m_originalHeight = this->height(); }Widget::~Widget() {delete ui; }void Widget::wheelEvent(QWheelEvent *event) {QWidget::wheelEvent(event);QPoint sroll = event->angleDelta();if(sroll.y() > 0)extendWindowsSize();elseshrinkWindowsSize(); }void Widget::extendWindowsSize() {if(this->width() > m_originalWidth + 300){return;}this->setMaximumSize(this->width() + 10, this->height() + 10);this->setMinimumSize(this->width() + 10, this->height() + 10); }void Widget::shrinkWindowsSize() {if(this->width() < m_originalWidth - 300){return;}//注意：順序不能顛倒this->setMinimumSize(this->width() - 10, this->height() - 10);this->setMaximumSize(this->width() - 10, this->height() - 10); }

main.cpp

#include "widget.h" #include <QApplication>int main(int argc, char *argv[]) {QApplication a(argc, argv);Widget w;w.show();return a.exec(); }

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