在QDialog构造函数中添加以下几行代码:
// 设置窗体最大化和最小化
Qt::WindowFlags windowFlag = Qt::Dialog;
windowFlag |= Qt::WindowMinimizeButtonHint;
windowFlag |= Qt::WindowMaximizeButtonHint;
windowFlag |= Qt::WindowCloseButtonHint;
setWindowFlags(windowFlag);
运行效果: