开关未正确更新

Question

在我的 flutter 应用程序中，我有这个小部件：

class MenuPage extends StatefulWidget {
  final List<Team> teams;
  final List<Game> games;

  const MenuPage({Key? key, required this.teams, required this.games})
      : super(key: key);

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

class _MenuState extends State<MenuPage> {
  int _currentIndex = 0;
  late TeamDataSource teamDataSource;
  List<Team> teams = [];
  List<Game> games = [];
  List<Widget> body = [];
  bool isSwitched = true;

  @override
  void initState() {
    teams = widget.teams;
    games = widget.games;
    teamDataSource = TeamDataSource(teamData: teams);

    body = [
      RankingTable(teams: teamDataSource),
      getMatches(),
    ];
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: body[_currentIndex],
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: _currentIndex,
        onTap: (int newIndex) {
          setState(() {
            _currentIndex = newIndex;
          });
        },
        items: const [
          BottomNavigationBarItem(
              label: "Ranking", icon: Icon(Icons.format_list_numbered)),
          BottomNavigationBarItem(
              label: "Matchs", icon: Icon(Icons.sports_soccer)),
        ],
      ),
    );
  }

  Widget getMatches() {
    return LayoutBuilder(
        builder: (BuildContext context, BoxConstraints constraints) {
      return ListView(
        children: [
          Switch(
            value: isSwitched,
            onChanged: (newValue) {
              setState(() {
                isSwitched = newValue;
                //print(isSwitched);
              });
            },
          ),
          for (var game in games)
            SizedBox(
              height: constraints.maxHeight,
              child: Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Expanded(
                    child: CachedNetworkImage(
                      imageUrl: game.homeTeamImage,
                      placeholder: (context, url) =>
                          CircularProgressIndicator(),
                      errorWidget: (context, url, error) =>
                          new Icon(Icons.error),
                    ),
                  ),
                  Padding(
                    padding: const EdgeInsets.fromLTRB(30, 0, 30, 0),
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        Text(
                          parseDate(game.date),
                          style: const TextStyle(
                              fontFamily:
                                  "Work Sans, BlinkMacSystemFont, Segoe UI, Roboto, Helvetica Neue, Arial, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol",
                              fontSize: 16),
                        ),
                        Text(
                          game.time.substring(0, 5),
                          style: const TextStyle(
                              fontFamily: "Changa", fontSize: 30),
                        )
                      ],
                    ),
                  ),
                  Expanded(
                    child: CachedNetworkImage(
                      imageUrl: game.awayTeamImage,
                      placeholder: (context, url) =>
                          CircularProgressIndicator(),
                      errorWidget: (context, url, error) =>
                          new Icon(Icons.error),
                    ),
                  )
                ],
              ),
            )
        ],
      );
    });
  }
}

在 getMatches 函数中，开关小部件未正确更新。当我尝试切换按钮时，它总是回到真实值。我认为那是因为我正在使用 returns 一个小部件的函数，如果我将开关小部件放在构建方法中，它应该可以工作。有人可以告诉我我的代码有什么问题吗？

Answer 1

就是这个问题；将您在 getMatches 中返回的小部件提取为单独的小部件（使用其自己的 build 方法 - 首选方法）或只是包装StatefulBuilder 小部件内的 LayoutBuilder 小部件，它提供了一个闭包，用于将 setState 触发的更改封装到仅此小部件，如：

Widget getMatches() {

 return StatefulBuilder(
   builder: (BuildContext context, StateSetter setState) {
      return LayoutBuilder() // rest of the code
   }
 );
}

开关未正确更新

Switch is not updating properly

setstate

dart

flutter