QTimer *timer1 = new QTimer(this);   
 QTimer *timer2 = new QTimer(this);
 //QTimer *timer3 = new QTimer(this); 
    startTimer(5000); 
 connect( timer1, SIGNAL(timeout()), this, SLOT(upAction()) );
 timer1->start(5000);
 //timer1->stop();
 //timer1->setInterval(5000); 
 connect( timer2, SIGNAL(timeout()), this, SLOT(stopAction()) );
 timer2->start(10000);
我想执行upAction()) 5s然后执行stopAction()) 5s。依次循环,但是打开串口之后,过5s会开始执行upAction()) ,但是不会停下来,这是为什么?怎么修改程序