没入モードのシステムバーを非表示にする

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

    val windowInsetsController =
        WindowCompat.getInsetsController(window, window.decorView)
    // Configure the behavior of the hidden system bars.
    windowInsetsController.systemBarsBehavior =
        WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE

    // Add a listener to update the behavior of the toggle fullscreen button when
    // the system bars are hidden or revealed.
    ViewCompat.setOnApplyWindowInsetsListener(window.decorView) { view, windowInsets ->
        // You can hide the caption bar even when the other system bars are visible.
        // To account for this, explicitly check the visibility of navigationBars()
        // and statusBars() rather than checking the visibility of systemBars().
        if (windowInsets.isVisible(WindowInsetsCompat.Type.navigationBars())
            || windowInsets.isVisible(WindowInsetsCompat.Type.statusBars())) {
            binding.toggleFullscreenButton.setOnClickListener {
                // Hide both the status bar and the navigation bar.
                windowInsetsController.hide(WindowInsetsCompat.Type.systemBars())
            }
        } else {
            binding.toggleFullscreenButton.setOnClickListener {
                // Show both the status bar and the navigation bar.
                windowInsetsController.show(WindowInsetsCompat.Type.systemBars())
            }
        }
        ViewCompat.onApplyWindowInsets(view, windowInsets)
    }
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    ...

    WindowInsetsControllerCompat windowInsetsController =
            WindowCompat.getInsetsController(getWindow(), getWindow().getDecorView());
    // Configure the behavior of the hidden system bars.
    windowInsetsController.setSystemBarsBehavior(
            WindowInsetsControllerCompat.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
    );

    // Add a listener to update the behavior of the toggle fullscreen button when
    // the system bars are hidden or revealed.
    ViewCompat.setOnApplyWindowInsetsListener(
        getWindow().getDecorView(),
        (view, windowInsets) -> {
        // You can hide the caption bar even when the other system bars are visible.
        // To account for this, explicitly check the visibility of navigationBars()
        // and statusBars() rather than checking the visibility of systemBars().
        if (windowInsets.isVisible(WindowInsetsCompat.Type.navigationBars())
                || windowInsets.isVisible(WindowInsetsCompat.Type.statusBars())) {
            binding.toggleFullscreenButton.setOnClickListener(v -> {
                // Hide both the status bar and the navigation bar.
                windowInsetsController.hide(WindowInsetsCompat.Type.systemBars());
            });
        } else {
            binding.toggleFullscreenButton.setOnClickListener(v -> {
                // Show both the status bar and the navigation bar.
                windowInsetsController.show(WindowInsetsCompat.Type.systemBars());
            });
        }
        return ViewCompat.onApplyWindowInsets(view, windowInsets);
    });
}