Add automatic per-app languages preferences generation

[Arthur-GYT]

All is in the title ^^.

https://developer.android.com/guide/topics/resources/app-languages

[westnordost]

Oh, that's interesting.

Currently, there is an in-app selection option for that. Should that not be shown on Android 13+ then? Have you tested how the in-system-settings version of it interacts with when setting it in the app?

[Arthur-GYT]

Oh, that's interesting.

Currently, there is an in-app selection option for that. Should that not be shown on Android 13+ then? Have you tested how the in-system-settings version of it interacts with when setting it in the app?

I have tested and per-app system has priority (by which I mean that the in-app system does not take the change into account). I think we can make it so that when we click on the segment, it returns directly to the application settings when this is supported. What you think about this idea @westnordost ?

[westnordost]

Yes, I think if this feature was to be enabled, then for Android 13+, that option in the StreetComplete settings should lead the user directly to the Android system settings or even not be displayed at all, including deleting/ignoring the preference if set before.

However, I do remember that one reason why this language selection setting was introduced in the first place because users were simply unable to select certain languages in the system language selection. So, are all languages into which StreetComplete is translated to even available in the system language selection? If not, then this new Android 13+ feature does not solve the use case for which the in-app language-selector was introduced in the first place.

[westnordost]

So, to move this forward, someone would need to check that on Android 13+ all languages selectable in the app are also selectable from the system selector. Actually, I found this file in the Android source code. I think these are the languages that can be selected in the Android system locale screen. Didn't look through / compare it with our list yet. However, it looks like at least Esperanto is missing.

https://android.googlesource.com/platform/frameworks/base/+/refs/tags/android-13.0.0_r83/core/res/res/values/locale_config.xml

I wonder, would then Esperanto be displayed in this per-app languages screen?

[riQQ]

On Android 14 I checked another app that offers the language setting and there's no Esperanto. But I don't know if this app actually has this language and if this is required for the option to show up in the systems language picker dialogue.

[westnordost]

Yes, that system language picker dialog only displays the languages that are actually supported by the app. Question is, if a language is supported by the app but not by the system at large, will it be displayed in that per-app system language picker?