QT Widgets not responding to touch event sometimes

[Sreejith]

Hi ,

I'm facing weird behavior with Qt touch events with widgets. The touch is not working with widgets sometimes.
I'm using Qt 5.6.2 and developed one application with some widgets (3 QComboBox and submit buttons). I have enabled tslib while compiling and it got compiled successfully.

After running application I can control all the widgets with touch. Then after sometime all widgets will stop responding to touch. Again after sometime it may respond. When the touch is not working, at that time the mouse click is working fine. And also I confirmed mouse is working fine always.

If I rerun the Qt application, again touch will work for sometime.

I have confirmed ts_calibrate and ts_test are working fine. It is working continuously.

I have set below variables to run the Qt app with touch-

export TSLIB_CALIBFILE=/etc/pointercal
export TSLIB_CONFFILE=/etc/ts.conf
export TSLIB_CONSOLEDEVICE=none
export TSLIB_FBDEVICE=/dev/fb0
export TSLIB_TSDEVICE=/dev/input/event0
export TSLIB_PLUGINDIR=/usr/lib/ts/
export QT_QPA_PLATFORM_PLUGIN_PATH=/plugins
export QT_QPA_PLATFORM=linuxfb
export QWS_MOUSE_PROTO=/dev/input/event0

And I'm running application as -
./qt_app -plugin tslib

Is anyone faced this issue? And how to solve this?

Thanks,

[dheerendra]

When you said after some time what does it mean ? Are you in the same UI where it responded for touch earlier ?. Say some UI displayed and same UI e.g after 10 seconds stops responding to touch ? Or are you going to different UI and that UI stops responding ?

In order to isolate the issue, Can you just have some simple one widget & start looking for the touch events ? Since you said that mouse events are coming, I don't see issue with event processing.

[Sreejith]

Hi @dheerendra ,

I have only one ui and same only working for sometimes and stops.
The time it works is random. Sometimes it works more time and stops. And sometimes it will start working again.

I believe the issue is the widgets with touch. Because whenever the widgets not responding, I can see the mouse cursor is moving properly whenever I'm touching.

I created a simple ui and tried. There also I can see the same issue.

[dheerendra]

Hard to figure out what is the issue. I tried with our board we are not seeing the same behaviour. If it is failing with Qt widgets, can you check with QML application. It is just to eliminate the possibilities.

[drd1988on]

Hi
I am facing the touch issue in QML.
Whenever I tried to random clicks on my UI sometimes am getting Invalid touch state in command promt while testing on my hardware.

Regards
Divya

[nishiokas]

Hi

The touch is not working with widgets sometimes.

I'm in the same situation.
Qt 5.9.1
Qt Quick application
・the touch isn't work sometimes, suddenly.
・The application is working in our product that it's like vending machine.
・There are working over 1000 machines in the market everyday. only 2-3 machines have this issue about a month.
・When in this situation, USB-mouse is working.( in other word, I can touch the button on the screen with USB-mouse)
・And If I run another application, the touch is working in this one.

Is anyone have any information?
Thanks.

[MicHes]

Hi everyone,
has anyone found a solution to this problem?

We are having the same problem with Qt 5.15.2 for x86 (32 bit; standard widgets QApplication, no QML in use); the touch screens we are using (ILITEK V5000 and ILITEK Multitouch) are sending TouchEvents to Qt which are then synthesized into Qt mouse events for button clicks etc.

This just stops at (seemingly) random times, leaving the application inoperable until we restart the application/X11. At the same time, other applications opened seem to work without a problem.

Is there a way to fix this? Is this a known bug in Qt 5.15.2? Can anyone give any hints what to try?

Greetings, Michael.

[Newpronik]

@MicHes
Hey i have same problem. I use qt 6.3.0 pyside6.
This bug occurs when you open new dialog and set atrribute qt::WA_DeleteOnClose

For temporaly i fixed this issue, i removed this attribute and set all dialogs like a main class attrubute.
So dont remove any c++ object and it ll fixed but i think its awful fix. I need solution too but i couldnt find anything about this.

[JoeCFD]

This post is deleted!