1、切换前垂直布局

2、切换后水平布局

3、关键代码

    qDebug() << "开始切换布局";QWidget *widget = centralWidget();QLayout *layout = widget->layout();if(layout){while(layout->count()){QLayoutItem *item = layout->takeAt(0);if(item->layout()){delete item->layout();}else{if(item->widget()){delete item->widget();}}delete item;}delete layout;}layout = new MyHBoxLayout;QLabel *label1 = new MyLabel("Label 1");QLabel *label2 = new MyLabel("Label 2");QLabel *label3 = new MyLabel("Label 3");label1->setStyleSheet("QLabel {background : red}");label2->setStyleSheet("QLabel {background : green}");label3->setStyleSheet("QLabel {background : blue}");layout->addWidget(label1);layout->addWidget(label2);layout->addWidget(label3);widget->setLayout(layout);qDebug() << "完成切换布局";