How can I stop Timer period in Flutter? - flutter

Question

class _LiftButtonLayerState extends State<LiftButtonLayer> {
late Timer _timer;
late double _timeElapsed;
var isPause = false;
var isTrue = true;
#override
void initState() {
super.initState();
}
repeatDownActivate() {
_timeElapsed = 0;
final timer = Timer.periodic(Duration(milliseconds: 200), (timer) {
liftDownButton.postReq();
print("down singal 5per 1 second ");
});
}
Container(
width: 180,
height: 60,
child: GFButton(
onPressed: () {
repeatUpActivate();
print('clicked Up Button');
},
text: '▲',
textStyle: const TextStyle(
fontSize: 26,
color: GFColors.WHITE,
),
shape: GFButtonShape.pills,
size: GFSize.LARGE,
buttonBoxShadow: true,
)),
I found out that I can use Timer.cancel() from Flutter's Timer library.
I made a function for timer.cancel() , and applied timer.cancel() to onPressed on the new other button, but it doesn't work.
repeatUpActivate(isTrue) {
if (isTrue == '200') {
_timeElapsed = 0;
var _timer = Timer.periodic(Duration(milliseconds: 200), (timer) {
liftUpButton.postReq();
print("down singal 5per 1 second (ms)");
});
} else {
return false;
}
}
child: GFButton(
onPressed: () {
repeatUpActivate('900');
},

Answer 1

can this help you? to better understand how to cancel a timer
late Timer _timer;
int i = 0;
#override
void initState() {
// TODO: implement initState
super.initState();
launchTimer();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text("Test")),
body: Center(
child: ElevatedButton(
child: Text('stop timer'),
onPressed: () async {
stopTimer(stopTimer: true);
},
),
),
);
}
void launchTimer() {
_timer = Timer.periodic(Duration(milliseconds: 200), (timer) {
i++;
print(i);
});
}
void stopTimer({required bool stopTimer}) {
if (stopTimer) {
_timer.cancel();
}
}