Avoid QTimer to emit timeout signal

Question

I have started Timer to wait for certain condition to be true. IF condition is true then I stop timer and dont want timeout signal to emit or execute connnected slot. But if condition is false within specified time then its allright to emit signal timeout(). But whatever is the case it always emit timeout signal. I have used blockSignals ( true ) as well and it doesnt work. Can some one please advice me.

void timerStart( QTimer* timer, int timeMillisecond )
{
  timer = new QTimer( this );
  timer->setInterval( timeMillisecond );
  timer->setSingleShot( true );
  connect( timer, SIGNAL( timeout() ), this, SLOT( noRespFrmServer( ) ) ) ;
  //timer->start( timeMillisecond );
  timer->start();
}
void timerStop( QTimer* timer )
{
  connect( timer, SIGNAL( destroyed( timer ) ), this, SLOT( stopTimerbeforeTimeout( ) ) );
  qDebug() << " we are in timer stop";
  if( timer )
    {
      timer->stop();
      timer->blockSignals( true );
      delete timer;
    }
}

Also in timerStop function I have tried to emit destroyed signal but I got response that it fails to connect. pLease advice me.

A couple of things look suspect - in timerStart() you ignore the passed parameter timer, and don't store your newly created timer, so you have no way to stop it. Where do you get the timer you pass to timerStop()? Did you perhaps mean to pass QTimer*& to timerStart(), or to store the timer in a member or (ugh) global? — Toby Speight

ratchet freak ratchet freak · Accepted Answer · 2015-08-27T14:58:43

void timerStart( QTimer* timer, int timeMillisecond )
{
  timer = new QTimer( this );
  timer->setInterval( timeMillisecond );
  timer->setSingleShot( true );
  connect( timer, SIGNAL( timeout() ), this, SLOT( noRespFrmServer( ) ) ) ;
  //timer->start( timeMillisecond );
  timer->start();
}

This doesn't actually return the timer you just created. You want something like:

QTimer *timerStart(int timeMillisecond )
{
  QTimer* timer = new QTimer( this );
  timer->setInterval( timeMillisecond );
  timer->setSingleShot( true );
  connect( timer, SIGNAL( timeout() ), this, SLOT( noRespFrmServer( ) ) ) ;
  //timer->start( timeMillisecond );
  timer->start();
  return timer;
}

Then you can pass the returned timer into the stop function though I suggest you use deleteLater instead of straight up deleting it:

void timerStop( QTimer* timer )
{
  qDebug() << " we are in timer stop";
  if( timer )
    {
      qDebug() << " we are stopping the timer";
      timer->stop();
      timer->blockSignals( true );
      timer->deleteLater();
    }
}

Avoid QTimer to emit timeout signal

1 Answers