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

    setContentView(R.layout.activity_calculator);

    final View contentView = findViewById(R.id.fullscreen_content);

    // Set up an instance of SystemUiHider to control the system UI for
    // this activity.
    mSystemUiHider = SystemUiHider.getInstance(this, contentView, HIDER_FLAGS);
    mSystemUiHider.setup();

    // Set up the user interaction to manually show or hide the system UI.
    contentView.setOnClickListener(
        new View.OnClickListener() {
          @Override
          public void onClick(View view) {
            if (TOGGLE_ON_CLICK) {
              mSystemUiHider.toggle();
            } else {
              mSystemUiHider.show();
            }
          }
        });
  }
 @Override
 public void run() {
   mSystemUiHider.hide();
 }