How can I achieve "onContinuousPress" like behaviour?

Question

Let's say that I have this button somewhere in my Flutter app:

FloatingActionButton(
 backgroundColor: Theme.of(context).primaryColor,
 child: Icon(Icons.arrow_upward),
 onPressed: _someAction,
);

I want that _someAction() will be executed as long as my finger is tapping on the button (i.e. if I tap continuously for T seconds _someAction() should be execute N times,

where N=(int)(60/T + 1))

I looked into GestureDetector but couldn't find what I need there. I need this for example in order to increase/decrease some int value...

Answer 1

int _value = 0;
Timer _timer;

Widget build(BuildContext context) {
  return GestureDetector(
    onTapDown: (details) => _startTimer(true),
    onTapUp: (details) => _startTimer(false),
    child: FlutterLogo(size: 200),
  );
}

void _startTimer(bool start) {
  if (!start) {
    _timer.cancel();
    return;
  }
  // you can adjust the timings here
  _timer = Timer.periodic(Duration(milliseconds: 1), (_) => _myMethod());
}

// this method will be getting called as long as you hold
void _myMethod() => print("value = ${++_value}");