Showing Simple Duration timer left on screen - flutter

Question

Is there any simple way that i can show the time remaing in DURATION on screen?
void onTapDown(TapDownDetails details){
if(state == State.menu){
timer = Timer(duration = new Duration(seconds: 5), () {
state = State.playing;
});
print("STARTING IN [secondsremaing]");
}
or should i have to make it complex and implement any other class to do so ?

Answer 1

It will not work that way because a Timer will only call the given callback after the given Duration, but it will not tick for you.
If you want to show an updated widget indicating the remaining time, you will have to use a ticker and this is normally achieved by setting up an AnimationController.
In your case, it could look something like this (assuming you are in a StatefulWidget):
class _YourWidgetsState extends State<YourWidget> with SingleTickerProviderMixin {
AnimationController remainingTimeController;
#override
void initState() {
super.initState();
remainingTimeController = AnimationController(vsync: this, duration: const Duration(seconds: 5));
}
/// Used somewhere in your build method.
void onTapDown(TapDownDetails details) {
if(state == State.menu){
timer = Timer(duration = new Duration(seconds: 5), () {
state = State.playing;
});
print("STARTING IN [secondsremaing]");
}
}
#override
Widget build(BuildContext context) {
// Obviously return your other widgets in here as well.
return AnimatedBuilder(
animation: remainingTimeController,
builder: (context, _) => Text('${remainingTimeController.value * 60 * 5}'),
);
}
}