QT获取屏幕和可用桌面大小

       QDesktopWidget* desktopWidget = QApplication::desktop();
    //获取设备屏幕大小
    QRect screenRect = desktopWidget->screenGeometry();
    double screenX = screenRect.width();
    double screenY = screenRect.height();
    //QMessageBox输出double型数值
    QMessageBox::information(this, QWidget::tr("Info"), "ScreenX:" + QString::number(screenX, 'g', 6));
    QMessageBox::information(this, QWidget::tr("Info"), "ScreenY:" + QString::number(screenY, 'g', 6));
    
    //获取可用桌面大小
    QRect deskRect = desktopWidget->availableGeometry();
    double availableScreenX = deskRect.width();
    double availableScreenY = deskRect.height();
    QMessageBox::information(this, QWidget::tr("Info"), "availableScreenX:" + QString::number(availableScreenX, 'g', 6));
    QMessageBox::information(this, QWidget::tr("Info"), "availableScreenY:" + QString::number(availableScreenY, 'g', 6));