一、過載resizeEvent

1、新增mymessagebox.cpp檔案

#include "mymessagebox.h"

MyMessageBox::MyMessageBox(QWidget *parent) :
    QMessageBox(parent),
    _width(0),
    _height(0)
{
}

void MyMessageBox::setMySize(int width, int height)
{
    _width = width;
    _height = height;
}

void MyMessageBox::resizeEvent(QResizeEvent *event
 
)
{
    setFixedSize(_width, _height);
}

2、新增mymessagebox.h檔案

#ifndef MYMESSAGEBOX_H
#define MYMESSAGEBOX_H

#include <QWidget>
#include <QMessageBox>
#include <QResizeEvent>

class MyMessageBox : public QMessageBox
{
    Q_OBJECT
public:
    explicit MyMessageBox(QWidget *parent = 0
 
);
    void setMySize(int width, int height);

signals:
    
public slots:

protected:
    void resizeEvent(QResizeEvent *event);

private:
    int _width;
    int _height;
};

#endif // MYMESSAGEBOX_H

3、在需要彈出MessageBox的地方新增程式碼

    MyMessageBox msgBox;
    msgBox.setMySize(640,480);//設定MessageBox的大小
    msgBox.setStyleSheet("
 
background-image:url(:/new/two/two_1.jpeg)");//顯示圖片
    msgBox.exec();//執行改變