Touchscreen on raspberry with mixxx > 2.1.8

[Lorenzo]

I've created a post also in the mixxx forum but i think this is a bug and is not correct to overcome it with a workaround.
I will copy-paste the message from the forum:

I’m using a raspberry and i have different touchscreens.
With mixxx versions < 2.1.8 (QT4) i had no problem at all.
Starting with mixxx 2.2 (QT5) all my thouscreens that act like touch devices stopped working.
The touchscreens that emulate a normal mouse still works, (in this kind of touchscreens if you drag over a web page the text will be selected as if you click and drag a real mouse).
The touchscreens that act as a touch devices are the one that, if in a web page you drag over the page, the page scroll, so a different behaviour with respect to a normal click-and-drag action done with a mouse.
Switching to mixxx > 2.1.8 had broke this compatibility, now all the touchscreens that raspbian handle like “touch devices” and not like “normal mouse” doesn’t work anymore.
How can i use the latest version of mixxx on this kind of devices?

[Lorenzo (bhestia)]

Update: same problem not just on raspbian but also on ubuntu mate

[Evan (ehendrikd)]

After changing my RP4 screen to a Waveshare DSI touch screen I also found that:

- Menus could not be clicked
- Library tree and table items could not be clicked
- Any skin buttons could be clicked fine

Some debugging later I found that (counter intuitively) commenting out the following line:

https://github.com/mixxxdj/mixxx/blob/c90e38b21131ad48f598c3fd14f8cbbf27860340/src/mixxx.cpp#L219

Fixed the issue and now the touchscreen works as expected. Are you in a position to compile Mixxx from source on your pi and confirm if this fixes the issue?

[Daniel Schürmann (daschuer)]

I can confirm this on Ubuntu Bionic.

Original this was introduced here to allow mutitouch.
https://github.com/mixxxdj/mixxx/pull/76

after removing this line
setAttribute(Qt::WA_AcceptTouchEvents)

multitouch still works here, so I guess qt has its own solution now and our own solution is broken.

Unfortunately after [Controls]", "touch_shift" for a right mouse click is now broken in the library. For the the buttons it is still working.

[Daniel Schürmann (daschuer)]

A PR https://github.com/mixxxdj/mixxx/pull/3164 is waiting for review that should fix the reported issues.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/10108