1.

 QMessageBox msgBox;
    msgBox.setText("LED测试");
    msgBox.setIcon(QMessageBox::Question);
    msgBox.setInformativeText("当前LED显示为红色?");
    msgBox.setStandardButtons(QMessageBox::Yes | QMessageBox::No);
    msgBox.setButtonText (QMessageBox::Yes,QString("是"));
    msgBox.setButtonText (QMessageBox::No,QString("否"));
    msgBox.setDefaultButton(QMessageBox::Yes);
    int ret = msgBox.exec();
    if(ret==QMessageBox::Yes)
    {
        qDebug()<<"QMessageBox::Yes";
    }
    else
    {
       qDebug()<<"QMessageBox::no";
    }