Question 362919 in Flutter Question posted in
The official Flutter documentation can be found here.

How to wait for Flutter's Timer.periodic to cancel?

I have a function which periodically checks a condition and I want the function to ONLY proceed once the condition is met. This seems like such a basic task, but for some reason I cannot find a good way to solve this.

When I call the function below, I always get ‘job not done yet’ first and then after three seconds ‘job done’. How can I make it proceed to the return statement only after the counter == 3 ?
Sorry if this is such a noob thing to ask. I used Google, I promise, but to no avail.

Future<String> delayTest() async {
    var counter = 0;
    await Timer.periodic(const Duration(seconds: 1), (timer) {
      counter++;
      if (counter == 3) {
        print('job done');
        timer.cancel();
      }
    });
   
    return ('job not done yet.');
  }
Tags:

2

Answers


  1. 0

    You should wait until timer gets canceled. Something like this:

    Future<String> delayTest() async {
  var counter = 0;
  const duration = Duration(seconds: 1);
  final timer = Timer.periodic(duration, (timer) {
    counter++;
    print('not done yet');
    if (counter == 3) {
      print('job done');
      timer.cancel();
    }
  });
  while (timer.isActive) {
    // waiting for the same time duration to check if timer is still active after it
    await Future.delayed(duration);
  }
  return 'done';
}
    Login or Signup to reply.
  2. 0

    If you want to wait 3 seconds
    You can use

    Future<String> delayTest() async {
   await Future.delayed(Duration(seconds: 3));

   return ('job not done yet.');
}
    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search