//在標頭檔案中加入
protected:
    closeEvent(QCloseEvent *event);


//函式主體部分
void MyWidget::closeEvent(QCloseEvent *event)//此函式在QWidget關閉時執行
{
     if(trayIcon->isVisible())
         this->hide();
     else
         {
               QMessageBox::information(this,"Notice","You can't close the window");
          }
     event-

當你想讓關閉視窗的時候，讓視窗銷燬，在建構函式中設定Qt::WA_DeleteOnClose標誌：setAttribute(Qt::WA_DeleteOnClose);

帶驗證