onBackPressed method

@override Future<bool> onBackPressed()

onBackPressed returns false to stop propagating the event, true in other cases

Implementation

@override
Future<bool> onBackPressed() async {
  if (fragmentsManager.size > 1) {
    fragmentsManager.pop();
    fragment = fragmentsManager.peek();
    setState(() {});
    return false;
  }
  if (isPressBackAgain()) {
    if ((DateTime.now().millisecondsSinceEpoch - _exitControl) <= 3000) {
      return true;
    } else {
      _exitControl = DateTime.now().millisecondsSinceEpoch;
      showPressBackAgainMessage();
      return false;
    }
  }
  return true;
}