堆栈窗体QStackedWidget

duanxin = new Cduanxin(0);
 pcall = new Ccall(0);
 connect(ui.pushButton, SIGNAL(clicked()), SLOT(OnDuanxin()));

 connect(ui.pushButton_2, SIGNAL(clicked()), SLOT(OnCall()));
 auto a = ui.stackedWidget->addWidget(pcall);
 ui.stackedWidget->insertWidget(0,duanxin);
 ui.stackedWidget->insertWidget(1,pcall);
 ui.stackedWidget->setCurrentIndex(1);