Add option to hide thumbnail on lock screen

[XiangRongLin]

What is it?

• Feature (user facing)

Description of the changes in your PR

• Readd option to not show thumbnail on the lock screen
• Setting is located under appearance

Fixes the following issue(s)

• closes [Regression] Option to not show video thumbnail in lockscreen #4489
• closes Option to not show thumbnail inside notification #4651

APK testing

app-debug.zip

Due diligence

• I read the contribution guidelines.

[Stypox]

Thank you!

I'm not sure if Appearance is the correct place for this setting. I'd put it into Notification, since at the end of the day the lockscreen thumbnail is strictly related to the notification. Or maybe let's rename Notification to Media or something else (which would also solve the naming clash with #2335). What's your opinion on this? @opusforlife2 @TobiGr

[Stypox]

This switch should be hidden on API <21, since the lockscreen thumbnail was not a feature until Android Lollipop

[XiangRongLin]

Is there a preference for doing this with xml only or programmatically hiding it with java code.

Edit: preference as in which type is more liked. not as in a setting. I see how this could be misunderstood.

[Stypox]

You have to do this programmatically by getting the preference object in the settings fragment for appearance and hiding it

[XiangRongLin]

XML only is also possible, hence my question
You have values/bool.xml with a value being false and values-v22/bool.xml with the same value being true. In the preference xml you then add app:isPreferenceVisible="@bool/{key}"
Same could be done for app:visibility, with the values being strings for gone, invisible and visible.

[Stypox]

This looks like obfuscation: even though it works, it's more of a workaround than a real solution. I'd use normal code like it's done in all other PreferenceFragments

[opusforlife2]

I'd put it into Notification, since at the end of the day the lockscreen thumbnail is strictly related to the notification.

Let's do this for now, @Stypox.

[XiangRongLin]

I'll adjust the PR when #4652 gets merged

[Stypox]

Reminder for future me: before merging this we should make sure it also fixes #4651

[XiangRongLin]

I rebased it on top of my other PR to avoid merge conflicts, so ignore this for now until that one is merged.
I also get a crash in an API 19 emulator when i open the notification settings. I currently don't want to figure it out, since debugging that is a pain with my potato of a laptop. I can try to figure it out in ~1Week, when i get my new PC (and don't mess up building it).

Edit: DHL sucks and im missing my pc case

[XiangRongLin]

New Pc, the crash doesn't occur anymore.

I didn't disable the setting in old android versions since the option now also hides the image inside the notification, whichs works on old version.

[Stypox]

I tested on Android 11 and 4.4 and everything works good. Thank you! :-D