Question

我已经面临这个问题一个星期了，但无法解决。我有一个带有3个选项卡的TabBarView，所有这些选项卡都是使用带文本的statefulwidgets构建的。我已经用只带有文本小部件的类重新创建了问题。

E/flutter ( 5455): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: NoSuchMethodError: The getter 'focusScopeNode' was called on null.
E/flutter ( 5455): Receiver: null
E/flutter ( 5455): Tried calling: focusScopeNode
E/flutter ( 5455): #0      Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)
E/flutter ( 5455): #1      Route.didPush.<anonymous closure> (package:flutter/src/widgets/navigator.dart:139:17)
E/flutter ( 5455): #2      _rootRunUnary (dart:async/zone.dart:1134:38)
E/flutter ( 5455): #3      _CustomZone.runUnary (dart:async/zone.dart:1031:19)
E/flutter ( 5455): #4      _FutureListener.handleValue (dart:async/future_impl.dart:139:18)
E/flutter ( 5455): #5      Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:680:45)
E/flutter ( 5455): #6      Future._propagateToListeners (dart:async/future_impl.dart:709:32)
E/flutter ( 5455): #7      Future._completeWithValue (dart:async/future_impl.dart:524:5)
E/flutter ( 5455): #8      Future._asyncComplete.<anonymous closure> (dart:async/future_impl.dart:554:7)
E/flutter ( 5455): #9      _rootRun (dart:async/zone.dart:1126:13)
E/flutter ( 5455): #10     _CustomZone.run (dart:async/zone.dart:1023:19)
E/flutter ( 5455): #11     _CustomZone.runGuarded (dart:async/zone.dart:925:7)
E/flutter ( 5455): #12     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:965:23)
E/flutter ( 5455): #13     _microtaskLoop (dart:async/schedule_microtask.dart:43:21)
E/flutter ( 5455): #14     _startMicrotaskLoop (dart:async/schedule_microtask.dart:52:5)
E/flutter ( 5455):

我已经阅读了 https://github.com/flutter/flutter/issues/45539 还有这个 Flutter - NoSuchMethodError: The getter 'focusScopeNode' was called on null 但是我仍然找不到解决问题的方法，也许我还没有找到正确的实现方法。

调试告诉我这是发生问题的确切时间：在flutter系统类navigator.dart中

@protected
  @mustCallSuper
  TickerFuture didPush() {
    return TickerFuture.complete()..then<void>((void _) {
      navigator.focusScopeNode.requestFocus(); // HERE IS WHERE HELL IS UNLEASHED
    });
  }

我的课程是 1.创建tabbarview的类：

class Lounge extends StatefulWidget {
  const Lounge({ Key key }) : super(key: key);
  @override
  _LoungeState createState() => _LoungeState();
}

    class _LoungeState extends State<Lounge> with SingleTickerProviderStateMixin {
      TabController _tabController;
      List<Widget> myWidgetList;
      List<Tab> myTabs = <Tab>[
        new Tab(icon: Icon(Icons.people)),
        new Tab(icon: Icon(Icons.location_on)),
        new Tab(icon: Icon(Icons.edit)),
      ];

      @override
      void initState() {
        super.initState();
        _tabController = TabController(vsync: this, length: myTabs.length);
        myWidgetList = <Widget>[Explore(),MyMap(),Edit()];
      }

      @override
      void dispose() {
        _tabController.dispose();
        super.dispose();
      }

      @override
      Widget build(BuildContext context) {
        return Scaffold(
            appBar: AppBar(
              title: TabBar(
                controller: _tabController,
                tabs: myTabs,
              ),
            ),
            body: TabBarView(
                physics: NeverScrollableScrollPhysics(),
                controller: _tabController,
                children: myWidgetList
            )
        );
      }
    }

构建选项卡的所有选项卡Material Widgets如下所示（探索是第一个）

class Explore extends StatefulWidget{
  @override
  _ExploreState createState()=> _ExploreState();
}
class _ExploreState extends State<Explore> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Explore questionsets',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: Scaffold(backgroundColor: Colors.blue[50],
          body: Center(
              child: Text("explore")
          ),
        )
    );
  }
}

我什至看到了这个https://gitmemory.com/issue/flutter/flutter/42829/552941774 这似乎不是我想采取的方式（尽管这是唯一可行的方法）。对你的帮助表示感谢。谢谢！

TabBarView提供错误未处理的异常：NoSuchMethodError：的getter'focusScopeNode'

0 个答案: