SystemUIExtensionsListen.kt

/**
 * Registers a listener which is informed when UI is shown (true) or hidden (false).
 */
fun Window.addSystemUIVisibilityListener(visibilityListener: (Boolean) -> Unit) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
        decorView.setOnApplyWindowInsetsListener { v, insets ->
            val suppliedInsets = v.onApplyWindowInsets(insets)
            // only check for statusBars() and navigationBars(), because captionBar() is not always
            // available and isVisible() could return false, although showSystemUI() had been called:
            visibilityListener(suppliedInsets.isVisible(WindowInsets.Type.statusBars() or WindowInsets.Type.navigationBars()))
            suppliedInsets
        }
    } else {
        @Suppress("DEPRECATION")
        decorView.setOnSystemUiVisibilityChangeListener {
            visibilityListener((it and View.SYSTEM_UI_FLAG_HIDE_NAVIGATION) == 0)
        }
    }
}