Countdown Timer Flutter Example

 

Timer myTimer;
Duration myDuration = Duration();

@override
void initState() {
super.initState();
resetTimer();
}

void resetTimer(){
setState(() =>
myDuration = Duration(minutes: 5));
}

 

 

void startTimer(){
myTimer = Timer.periodic(Duration(seconds: 1),(_) => addTime());
}

void stopTimer({bool resets = true}){
if (resets){
resetTimer();
}
setState(() => myTimer.cancel());
}

 

 

void addTime(){
final addSeconds = -1;
setState(() {
final seconds = myDuration.inSeconds + addSeconds;
if (seconds < 0){
myTimer.cancel();
} else{
myDuration = Duration(seconds: seconds);

}
});
}

 

 

Widget displayTimer(){
String strDigits(int n) => n.toString().padLeft(2,’0′);
final hours = strDigits(myDuration.inHours);
final minutes = strDigits(myDuration.inMinutes.remainder(60));
final seconds = strDigits(myDuration.inSeconds.remainder(60));
return Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
displayTimerUI(time: hours, header:’HOURS’),
SizedBox(width: 8,),
displayTimerUI(time: minutes, header:’MINUTES’),
SizedBox(width: 8,),
displayTimerUI(time: seconds, header:’SECONDS’),
]
);
}

Widget displayTimerUI({@required String time, @required String header}) =>
Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Container(
padding: EdgeInsets.all(8),
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.circular(20)
),
child: Text(
time, style: TextStyle(fontWeight: FontWeight.bold,
color: Colors.black,fontSize: 45)),
),
SizedBox(height: 30),
Text(header,style: TextStyle(fontSize: 18, color: Colors.white)),
],
);

 

 

Widget displayTimerButtons(){
final isTimerRunning = myTimer == null? false: myTimer.isActive;
final isTimerCompleted = myDuration.inSeconds == 0;
return isTimerRunning || isTimerCompleted
? Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
ElevatedButton(
style: ElevatedButton.styleFrom(
primary: Colors.black,
padding: EdgeInsets.symmetric(horizontal: 32, vertical: 16)
),
onPressed: (){
if (isTimerRunning){
stopTimer(resets: false);
}
},
child: Text(‘STOP’,style: TextStyle(fontSize: 20,color: Colors.white),)
),
SizedBox(width: 12,),
ElevatedButton(
style: ElevatedButton.styleFrom(
primary: Colors.black,
padding: EdgeInsets.symmetric(horizontal: 32, vertical: 16)
),
onPressed: stopTimer,
child: Text(‘RESET’,style: TextStyle(fontSize: 20,color: Colors.white),)
),
],
)
: ElevatedButton(
style: ElevatedButton.styleFrom(
primary: Colors.white,
padding: EdgeInsets.symmetric(horizontal: 32, vertical: 16)
),
onPressed: startTimer,
child: Text(‘Start Timer’,style: TextStyle(fontSize: 20,color: Colors.black),)
);
}

 

 

@override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.redAccent,
appBar: AppBar(title: Text(‘Flutter Count Down Timer Sample’)),
body: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
displayTimer(),
SizedBox(height: 100),
displayTimerButtons()
],
),
);
}