Android R：API 30：系统栏可见性更改回调

Question

I am trying to make my app a full screen app. On Api levels 29 and below, I am using onSystemUIVisibilityChange listener to handle visibility of certain views in my activity when the app is in full screen. But on api level 30, is there any similar callback to know when system bars(status bar and navigation bar) visibility changes? Since onSystemUIVisibilityChange is deprecated for API level 29 and above.

I am aware of activity.window.insetsController.show(WindowInsets.Type.systemBars()) to show and hide System bars. What I need is a callback when system bar visibility changes.

Answer 1

As mention in the documentation you can set a listener using
View.OnApplyWindowInsetsListener((view: View, window:WindowInsets) -> WindowInsets)
and then in the listener you can check whether the system bars are visible or not using WindowInsets.isVisible(Int) . Like so:

private val onWindowInsetApplied: (view: View, window:WindowInsets) -> WindowInsets = { view, windowInsets ->
    val areSystemBarsVisible = windowInsets.isVisible(WindowInsets.Type.systemBars())
    //Do something
    windowInsets
}

fun setListener() {
    View.OnApplyWindowInsetsListener(onWindowInsetApplied)
}

Answer 2

For Java developers, this is the java version of @ Kyzer Soze answer

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {

    decorView.setOnApplyWindowInsetsListener(new View.OnApplyWindowInsetsListener() {
        @Override
        public WindowInsets onApplyWindowInsets(View v, WindowInsets insets) {

            if (insets.isVisible(WindowInsets.Type.systemBars())) {
                Toast.makeText(MainActivity.this, "system bars are Visible",    
                                                       Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(MainActivity.this, "system bars are Invisible", 
                                                       Toast.LENGTH_SHORT).show();
            }

            return insets;
        }
    });

}

Make sure not to call setOnApplyWindowInsetsListener in below API-30, as it will raise runtime exception