Assuming related to How to setup night mode drawables as expected
I'm trying to implement the new AppCompat DayNight theme in my Android app while providing a theme switch in the settings.
Scenario:
As said theme switch was used, the "settings" activity recreated itself as a result of a call to AppCompatDelegate#setDefaultNightMode and AppCompatDelegate#applyDayNight (the latter is available to AppCompatActivity through its getDelegate() method). The text color was inverted, the background changed and the back arrow's color changed as well. So far so good.
As the user finished changing the app's theme, he would close the activity and continue using the app. What does he expect to happen? Exactly, the main activity should have changed its theme as well. How do we do this? Activity#recreate in Activity#onActivityResult.
The call to AppCompatDelegate#setDefaultNightMode triggers a change in the configuration, which, afaik, is being applied either by AppCompatDelegate#applyDayNight or as soon as another Activity resolves its theme & configuration in Activity#onCreate. The first applies for the settings activity, the second is what is happening now.
Now to the critical part: the app's resources are dispatched a configuration change, and are now being checked against their validity (resource qualification), and if that fails, they will be cleared from the cache so that new resources (in this case, drawables) are created in order to fully reflect the new theme & configuration.
Now as I've said, the back arrow in the settings activity did change its color, but this was not my own drawable, it was the default one that you get with getSupportActionBar.setDisplayHomeAsUpEnabled(true). In the main activity however, I did use my own drawables, for menu icons and other ui elements for example. These just didn't change. I'm using vector drawables, which get their color from the fillColor attribute.
TL;DR
To make the DayNight theme work for me, I have defined theme attributes for certain colors used throughout my app, also for icons (drawables). These attributes are populated by the one unified theme I'm using, and are referring to colors from values-night or values-notnight depending on the current configuration. This is a redundant indirection, but makes for a better style, at least in my opinion, when used together with default theme attributes such as textColorPrimary etc..
But: as it turns out, it doesn't work. Going the attribute-way, those attributes, which are in the end colors, loose their quality of being resource qualified (night or notnight) and therefore pass the "validity test" performed on configuration change, even if that's not what's supposed to happen. Thus, after I have changed the night mode, I end up with the old, wrong drawables.
To fix this I could e.g. simply
replace android:fillColor="?attr/myCustomAttributeColorXEitherNightOrNot" with android:fillColor="@color/colorXEitherNightOrNot".
But is that really what this is supposed to be like? Am I missing some important attributes-principle here, or is it a bug? I'd like to hear some thoughts on this.
