The Hundreds widget

hundreds.dart

class Hundreds extends StatefulWidget {
  Hundreds(this.stopwatch);

  final Stopwatch stopwatch;

  HundredsState createState() => new HundredsState(stopwatch);
}

class HundredsState extends State<Hundreds> {
  final Stopwatch stopwatch;
  int hundreds = 0;

  HundredsState(this.stopwatch);

  @override
  void initState() {
    timerListeners.add(onTick);
    super.initState();
  }

  void onTick(ElapsedTime elapsed) {
    if (elapsed.hundreds != hundreds) {
      setState(() {
        hundreds = elapsed.hundreds;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    String minutesStr = (hundreds % 100).toString().padLeft(2, '0');
    return new Text(minutesStr, style: timerTextStyle);
  }
}