setOnApplyWindowInsetsListener never called

Question

I would like to calculate the navigationBar height. I've seen this presentation : https://chris.banes.me/talks/2017/becoming-a-master-window-fitter-nyc/

So, I tried to use the method View.setOnApplyWindowInsetsListener(). But, for some reason, it's never called.

Does anyone knows why ? Any limitation there ?

I've tried to use it like this :

navBarOverlay.setOnApplyWindowInsetsListener { v, insets -> 
   Timber.i("BOTTOM = ${insets.systemWindowInsetBottom}")
   return@setOnApplyWindowInsetsListener insets
}

Note that my root layout is a ConstraintLayout.

Answer 1

I faced the same issue.

If your root view is ConstraintLayout and contains android:fitsSystemWindows="true" attr, the view consumed onApplyWindowInsets callbacks. So if you set onApplyWindowInsets on child views, they never get onApplyWindowInsets callbacks.

Or check your parent views consume the callback.

Answer 2

This is what I observed; in other words, your experience might be different.

[Layout for Activity]
<androidx.coordinatorlayout.widget.CoordinatorLayout
    android:id="@+id/coordinatorLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"    <--
    tools:context=".MyAppActivity">

    ...

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>

Notice android:fitsSystemWindows="true" in the outer most layout. As long as we have it, setOnApplyWindowInsetsListener() does get called.

class MyActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        ...

        ViewCompat.setOnApplyWindowInsetsListener(fab) { view, insets ->
            ...
            insets
        }
    }

Alternatively, if you are going for the "full screen", meaning you want your layout to extend to the status bar and the navigation bar, you can do something like the following.

override fun onCreate(savedInstanceState: Bundle?) {
    ...

    WindowCompat.setDecorFitsSystemWindows(window, false)    <--

    ViewCompat.setOnApplyWindowInsetsListener(fab) { view, insets ->
        ...
        insets
    }
}

The same idea is applicable when you are using a Fragment, as long as the Activity (that contains the Fragment) has either fitsSystemWindows in the outer most layout or you set your Activity as full screen.