How to have timer with variable duration in Flutter

Question

How can I make a timer that its speed increases every minute i.e. the timer duration decreases evey 1 minute in Flutter?

Answer 1

You could make just one Timer.periodic with your minimum period and use a static counter in the callback to mark off multiples of that variable period. This has the advantage of being easily extended to any number of tasks running at different periods -- all driven by the same timer.

import 'dart:async';
import 'dart:math';

const int minPeriod=1;
const int maxPeriod=10;
const double decreaseRate=0.1;

int variablePeriodSeconds(int t) {
  var p=decreaseRate*t;
  return max(maxPeriod-p.floor(),minPeriod); // simple linear decrease
}

void main() {
  int tTick=0;
  int tTock=0;
  final Duration minDuration = Duration(seconds: minPeriod);
  Timer timer = Timer.periodic(minDuration, (Timer timer) {
  print('tick');
  if(tTick-tTock >= variablePeriodSeconds(tTick)){
      print("TOCK!");
      tTock=tTick;
  }
  tTick++;
  });
}

The above code creates an explicit tTick counter, but the Timer object has an instance variable timer.tick that's pretty much good to go for this same purpose.