Your First Flutter App: Polishing the App

Apr 12 2022 Dart 2.14.1, Flutter 2.5, Visual Studio Code

Part 2: Build Out the App

17. Create a Callback

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Previous episode: 16. Challenge: Add Bonus Points Next episode: 18. Conclusion

This video was last updated on Apr 12 2022

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Let’s take a look at our Todo list. We were working to calculate and show the score. We’ve successfully wrapped up that task.

final VoidCallback onStartOver;
  const Score(
      {Key? key,
      required this.totalScore,
      required this.round,
      required this.onStartOver})
      : super(key: key);
    child: const Text('Start Over'),
    onPressed: () {
int _newTargetValue() => Random().nextInt(100) + 1;
void initState() {
    _model = GameModel(_newTargetValue());
        setState(() {
          _model.totalScore += _pointsForCurrentRound();
          _model.round += 1;
void _startNewGame() {

setState(() {

_model.totalScore = GameModel.scoreStart;
_model.round = GameModel.roundStart;
_model.current = GameModel.sliderStart; = _newTargetValue();
    totalScore: _model.totalScore,
    round: _model.round,
    onStartOver: _startNewGame)