Qt 之容器内的控件全屏

m_label = new QLabel();
    ui->stackedWidget->addWidget(m_label);
    ui->stackedWidget->setCurrentWidget(m_label);

ui->stackedWidget->removeWidget(m_label);
    m_label->setWindowFlags(Qt::Window);
    m_label->setScaledContents(true);
    m_label->showFullScreen();

m_label->setWindowFlags(Qt::Window);
这个语句很重要。