touch does not work sometimes while mouse press works fine.

[JoeCFD]

I have some dynamic layout changes in a Qt widgets GUI on touch screens. Widgets will be destroyed and created in these changes. In some switches, GUI is frozen to touch events while no problem for mouse presses. What could be the causes?

Ubuntu 22.04 and Qt 5.15.3

[SGaist]

Hi,

Is this freezing temporary ?
Can you trigger that repeatedly ?

[JoeCFD]

@SGaist not temporary. I can repeat the issue a few times, but randomly. Mainly this happens when layout changes too quickly.

[SGaist]

Strange... Out of curiosity, what requires these quick changes that triggers destruction and recreation of widgets ?

[JoeCFD]

@SGaist It is not a requirement to do quick changes. Personally, I will not abuse touch screen too much. But you never know what clients will do. If the app freezes, they will hate it especially in critical situations(life/death). We try to train the clients not to do it. However, better to fix it if possible.

[SGaist]

@JoeCFD it was merely to understand the logic and possibly find a better way to handle that. I must say that in life/death situations, I would rather have something else as input system than a touchscreen.

Did you try to run your application with all Qt logging enabled to spot something ?
Also, does dmesg give you a hint of something wrong then the freeze happen ?

[JoeCFD]

@SGaist It is a general practice to use touch screen in this field.
Not yet. I will take a look at it. Thank you for your advice.