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countdown.dart
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countdown.dart
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// Example on how to implement countdown using PausableTimer.periodic
import 'dart:async';
import 'package:pausable_timer/pausable_timer.dart';
void main() async {
// We make it "late" to be able to use the timer in the timer's callback.
late final PausableTimer timer;
var countDown = 5;
print('Create a periodic timer that fires every 1 second and starts it');
timer = PausableTimer.periodic(
Duration(seconds: 1),
() {
countDown--;
if (countDown == 0) {
timer.pause();
}
print('\t$countDown');
},
)..start();
print('And wait 2.1 seconds...');
print('(0.1 extra to make sure there is no race between the timer and the '
'waiting here)');
await Future<void>.delayed(timer.duration * 2.1);
print('By now 2 events should have fired: 4, 3\n');
print('We can pause it now');
timer.pause();
print('And we wait for 2 more seconds...');
await Future<void>.delayed(timer.duration * 2);
print("But our timer doesn't care while it's paused\n");
print('So we start it again');
timer.start();
print('And wait for 3.1 seconds more...');
await Future<void>.delayed(timer.duration * 3.1);
print('And we are done: 2, 1 and 0 should have been printed');
print('The timer should be unpaused, inactive, expired and not cancelled');
print('isPaused: ${timer.isPaused}');
print('isActive: ${timer.isActive}');
print('isExpired: ${timer.isExpired}');
print('isCancelled: ${timer.isCancelled}');
print('We can now reset it and start it again, now for 3 seconds');
countDown = 3;
timer
..reset()
..start();
print('And wait for 3.1 seconds...');
await Future<void>.delayed(timer.duration * 3.1);
print('And it should be done printing: 2, 1 and 0');
}