窗口的某些属性的状态发生改变时就会触发该事件

对应的事件类型包括

• QEvent::ToolBarChange,
• QEvent::ActivationChange,
• QEvent::EnabledChange,
• QEvent::FontChange,
• QEvent::StyleChange,
• QEvent::PaletteChange,
• QEvent::WindowTitleChange,
• QEvent::IconTextChange,
• QEvent::ModifiedChange,
• QEvent::MouseTrackingChange,
• QEvent::ParentChange,
• QEvent::WindowStateChange,
• QEvent::LanguageChange,
• QEvent::LocaleChange,
• QEvent::LayoutDirectionChange
• QEvent::ReadOnlyChange

需要重写的函数为：

 void QWidget::changeEvent(QEvent *event)

这里以WindowStateChange为例来说明

窗口刚出现时，窗口状态为Qt::WindowNoState

点击最大化按钮，窗口状态变为Qt::WindowMaximized

点击最小化按钮时，窗口状态变为Qt::WindowMinimized

每次状态改变时，弹出对话框提示

 代码如下：

    void changeEvent(QEvent* ev){//如果窗口状态发生了改变if(ev->type()==QEvent::WindowStateChange){//如果窗口为最大化if(this->windowState().testFlag(Qt::WindowMaximized)){QMessageBox::information(this,"","is max!");}else if(this->windowState().testFlag(Qt::WindowMinimized)){QMessageBox::information(this,"","is mini!");}else if(this->windowState().testFlag(Qt::WindowNoState)){QMessageBox::information(this,"","is normal!");}}else if(ev->type()==QEvent::WindowTitleChange){}//....还有其他改变类型}

学习链接：https://github.com/0voice