Flutter 如何仅在特定页面上显示 AlertDialog

Question

我正在用颤振构建一个国际象棋时钟。当我在设置页面中更改时钟持续时间时，我想要求用户使用警报对话框进行确认。我希望警报对话框现在只出现在主页中，它会在我在设置页面中更改持续时间后立即出现。

当我更改持续时间时，我正在使用提供程序来管理状态，我将布尔值更改为 true。然后在主页中检查布尔值是否为真，然后运行警报对话框代码。我尝试将对话框代码放入future delay.Zero，但没有成功。

现在主页在我更改设置并弹出警报对话框后立即重建。

我的代码：

// home page code
class HomePage extends StatefulWidget {
  const HomePage({
    Key? key,
  }) : super(key: key);

  @override
  _HomePageState createState() => _HomePageState();
}


class _HomePageState extends State<HomePage>
    with TickerProviderStateMixin, WidgetsBindingObserver {

// code for initstate and logic

late AnimationController _whiteControl;
  late AnimationController _blackControl;

  int whiteTime = 1;
  int blackTime = 1;

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

    WidgetsBinding.instance!.addObserver(this);

    _whiteControl = AnimationController(
      vsync: this,
      duration: Duration(seconds: whiteTime * 60),
    );

    _blackControl = AnimationController(
      vsync: this,
      duration: Duration(seconds: blackTime * 60),
    );

@override
  void dispose() {
    WidgetsBinding.instance!.removeObserver(this);
    _whiteControl.dispose();
    _blackControl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    var gameState = Provider.of<GameState>(context, listen: false);
    final ChoiceDialog resetChoice = ChoiceDialog(
      buttonOkOnPressed: () {
        _blackControl.reset();
        _whiteControl.reset();
        gameState.isgameChanged = false;
        Navigator.pop(context);
      },
      buttonCancelOnPressed: () {
        gameState.isgameChanged = false;
        Navigator.pop(context);
      },
    );

    if (gameState.isGameStarted && gameState.isgameChanged) {
      Future.delayed(Duration.zero, () {
        print('???? Game Changed ');
        resetChoice.show(context);
      });
    }
 print('???? Rebuilding Home Page ---');
    return Scaffold();
//reset of homepage code

设置页面代码：

class SettingsPage extends StatelessWidget {
  const SettingsPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Settings'),
      ),
      body: Column(
        children: [
          Expanded(
            child: ListView.builder(
                itemCount: gamesList.length,
                itemBuilder: (context, index) {
                  return Consumer<GameState>(
                    builder: (context, _gameState, child) {
                      return GestureDetector(
                        onTap: () {
                          _gameState.changeGame(gamesList[index]);
                        },
                        child: Container(),
                      );
                    },
                  );
                }),
          )
        ],
      ),
    );
  }
}

提供者状态逻辑：

class Game {
  final String name;
  final int whiteTime;
  final int blackTime;

  Game({
    required this.name,
    required this.whiteTime,
    required this.blackTime,
  });
}

class GameState with ChangeNotifier {
  bool turnWhite = false;
  bool turnBlack = false;
  bool isgameChanged = false;
  bool isClocksFinished = false;
  bool isPaused = false;
  bool isGameStarted = false;
  bool resetGame = false;

  int white = 0;
  int black = 0;

  Game _currentGame = gamesList[0];

  Game get currentGame => _currentGame;

  bool get isWhiteTurn => turnWhite;

  void resetGameClocks() {
    resetGame = true;
    notifyListeners();
  }

  void setTurnWhite() {
    turnWhite = true;
    turnBlack = false;
    isGameStarted = true;
    notifyListeners();
  }

  void setTurnBlack() {
    turnWhite = false;
    turnBlack = true;
    isGameStarted = true;
    notifyListeners();
  }

  void changeGame(Game game) {
    _currentGame = game;
    isgameChanged = true;
    white = game.whiteTime;
    black = game.blackTime;
    notifyListeners();
  }
}

项目仓库：https://github.dev/tonydavidx/chess-clock-app/tree/dev

Answer 1

我已经检查了你的代码，你在主页屏幕的初始点/起点犯了一个错误，请避免这种情况

如果您确实需要在开始时执行一些逻辑或代码，则永远不要在返回小部件的构建函数之前初始化或放置您的代码，然后将其放入 initstate() 或您的提供程序构造函数中并正确处理。

这是您所面临问题的根本原因。