I am using Qt 4.8.3 on a small ARM embedded Linux device with a touchscreen. I have my touchscreen configured with tslib and calibrated it so there is a pointercal file in /etc/. The locations of my touch events work just fine but no matter what I get a QEvent for Mouse Move before Mouse Press or Mouse Release Events. Furthermore, I don't get any Mouse Related Events until I physically lift my finger from the touchscreen. I need normal behavior where I press on the touchscreen and receive a mouse down event immediately and then my move events ( if there are any ) and then a mouse release event when I lift my finger.

Qt Code: 
  1. So what I'm seeing from the point of view of events received when I pressed down and then release looks like:
  2.  
  3.     50 SockAct <-- Received right at press down
  4.                <-- NO Other events received until press released
  5.                <-- Now release by lifting finger from screen
  6.     50 SockAct <-- Immediately received a 50 ( SockAct ) and the rest of the events below:
  7.     2          <-- 2 == mouse down
  8.     2          <-- 2 == mouse down
  9.     3          <-- 3 == mouse release / up
  10.     3          <-- 3 == mouse release / up
  11.     77         <-- 77 == redraw
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I've run 'evtest' on my /dev/input/touchscreen device in Linux and certainly see a touch down event immediately when pressing down on the screen. And I do not get a mouse release event until I lift my finger, so the driver behaves as expected. There are also no 'repeat' touch down events when I press - it is just one event for one press down , but behaves correctly.

I'm not sure why I'm seeing the behavior I do. There must be a translation issue between Qt and the input device.

Furthermore, If I add a small 3ms delay in processing my MouseButtonRelease received event, then I get desired behavior in terms of how the app works but I still do not receive my Mouse events until I release the press. I should not have to add a delay at all, I would expect my mouse down to happen, then any moves, and finally a mouse up event in turn

Does anybody know how to fix this or what may be causing this?? Thank you very much!

--

I don't see the following printed out until I actually lift my finger:

Qt Code: 
  1. ...
  2.     MOVE TYPE:  5 
  3.     "Mouse move (382,129)" 
  4.     MOUSE BUTTON PRESS TYPE:  2 
  5.     "Mouse Button Press (1)" 
  6.     MOUSE BUTTON RELEASE TYPE:  3 
  7.     "Mouse Button Release (1)" 
  8.     ....
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Here is my eventFilter where I examine my received events in my App:

Qt Code: 
  1. ////////////////////////////////////////////////////////////////////////////////////////////////////////////
  2.             // Just for kicks print out the mouse position
  3.             if (event->type() == QEvent::MouseButtonPress)
  4.             {
  5.                 qDebug() << "MOUSE BUTTON PRESS TYPE: " << event->type();
  6.                 QMouseEvent *mouseEvent = static_cast<QMouseEvent*>(event);
  7.                 qDebug() << QString("Mouse Button Press (%1)").arg(mouseEvent->button());
  8.             }
  9.             if (event->type() == QEvent::MouseMove)
  10.             {
  11.                 qDebug() << "MOVE TYPE: " << event->type();
  12.                 QMouseEvent *mouseEvent = static_cast<QMouseEvent*>(event);
  13.                 qDebug() << QString("Mouse move (%1,%2)").arg(mouseEvent->globalX()).arg(mouseEvent->globalY());
  14.             }
  15.             if (event->type() == QEvent::MouseButtonRelease)
  16.             {
  17.                 qDebug() << "MOUSE BUTTON RELEASE TYPE: " << event->type();
  18.                 QMouseEvent *mouseEvent = static_cast<QMouseEvent*>(event);
  19.                 delay();
  20.                 qDebug() << QString("Mouse Button Release (%1)").arg(mouseEvent->button());
  21.                 //return true; // Gobble the event
  22.             }
  23.             ////////////////////////////////////////////////////////////////////////////////////////////////////////////
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Here is my delay function:

Qt Code: 
  1. void Monitor::delay()
  2.     {
  3.         QTime dieTime = QTime::currentTime().addMSecs(3);
  4.         while( QTime::currentTime() < dieTime )
  5.         QCoreApplication::processEvents(QEventLoop::AllEvents, 100);
  6.     }
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