Change navigation bar icon color on Android

Question

If you are using API 27 (Android 8.1) or greater, you can achieve it with this in your theme:

<item name="android:windowLightNavigationBar">true</item>

You can create a folder called values-v27 and place a version of your theme (in styles.xml) with a light navigation bar and the above code to get dark navigation bar buttons.
This way, users with Android 8.0 or lower will get the standard (black) navigation bar while users with Android 8.1 or greater will get a white navbar with dark buttons.

Starting from Android O it gets really straightforward, as you could just:

View.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR);

For this to take effect, the window must request FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS but not FLAG_TRANSLUCENT_NAVIGATION.

Documentation: https://developer.android.com/reference/android/view/View.html#SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR

You can adjust windowLightNavigationBar = true/false and navigationBarColor = @color/yourColorId

so there're 4 cases, I've made an experiment:

In short, you don't want windowLightNavigationBar= false while navigationBarColor=White

or

windowLightNavigationBar= true while navigationBarColor=Black (this will be wired on SOME devices)