android studio remove navigation bar

    protected void onResume() {
        super.onResume();
        View decorView = getWindow().getDecorView();
        // Hides the status and navigation bar until the user clicks
        // on the screeen.
        int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                | View.SYSTEM_UI_FLAG_FULLSCREEN;
        decorView.setSystemUiVisibility(uiOptions);