Android flatter:setState（）或markNeedsBuild（）在小部件树被锁定时调用。。。方向改变时

我想创建一个应用程序，其UI可以根据设备方向进行更新。在Portait布局中，我使用抽屉来显示一些元素（）。在横向布局中，没有抽屉，但元素显示在屏幕左侧的一列中（）。当抽屉关闭时，程序工作

但是，当我在抽屉打开的情况下，将方向从portait切换到横向时，我得到了“当小部件树被锁定时调用setState（）或markNeedsBuild（）的错误” 堆栈提供以下信息：

Built build\app\outputs\apk\debug\app-debug.apk.
I/FlutterActivityDelegate(28527): onResume setting current activity to this
I/flutter (28527): PORTRAIT LAYOUT!!!!!!!!!!!!!!!!!!!!!!
I/hwaps   (28527): JNI_OnLoad
I/flutter (28527): LANDSCAPE LAYOUT!!!!!!!!!!!!!!!!!!!!!!
I/flutter (28527): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (28527): The following assertion was thrown while finalizing the widget tree:
I/flutter (28527): setState() or markNeedsBuild() called when widget tree was locked.
I/flutter (28527): This _ModalScope<dynamic> widget cannot be marked as needing to build because the framework is
I/flutter (28527): locked.
I/flutter (28527): The widget on which setState() or markNeedsBuild() was called was:
I/flutter (28527):   _ModalScope<dynamic>-[LabeledGlobalKey<_ModalScopeState<dynamic>>#e1f0f](state:
I/flutter (28527):   _ModalScopeState<dynamic>#830e3)
I/flutter (28527):
I/flutter (28527): When the exception was thrown, this was the stack:
I/flutter (28527): #0      Element.markNeedsBuild.<anonymous closure> (package:flutter/src/widgets/framework.dart:3453:9)
I/flutter (28527): #1      Element.markNeedsBuild (package:flutter/src/widgets/framework.dart:3462:6)
I/flutter (28527): #2      State.setState (package:flutter/src/widgets/framework.dart:1141:14)
I/flutter (28527): #3      _ModalScopeState._routeSetState (package:flutter/src/widgets/routes.dart:464:5)
I/flutter (28527): #4      ModalRoute.setState (package:flutter/src/widgets/routes.dart:562:30)
I/flutter (28527): #5      ModalRoute.changedInternalState (package:flutter/src/widgets/routes.dart:1018:5)
I/flutter (28527): #6      _ModalRoute&TransitionRoute&LocalHistoryRoute.removeLocalHistoryEntry (package:flutter/src/widgets/routes.dart:348:7)
I/flutter (28527): #7      LocalHistoryEntry.remove (package:flutter/src/widgets/routes.dart:296:12)
I/flutter (28527): #8      DrawerControllerState.dispose (package:flutter/src/material/drawer.dart:201:20)
I/flutter (28527): #9      StatefulElement.unmount (package:flutter/src/widgets/framework.dart:3821:12)
I/flutter (28527): #10     _InactiveElements._unmount (package:flutter/src/widgets/framework.dart:1697:13)
I/flutter (28527): #11     _InactiveElements._unmount.<anonymous closure> (package:flutter/src/widgets/framework.dart:1695:7)
I/flutter (28527): #12     ComponentElement.visitChildren (package:flutter/src/widgets/framework.dart:3676:14)
I/flutter (28527): #13     _InactiveElements._unmount (package:flutter/src/widgets/framework.dart:1693:13)
I/flutter (28527): #14     _InactiveElements._unmount.<anonymous closure> (package:flutter/src/widgets/framework.dart:1695:7)
I/flutter (28527): #15     ComponentElement.visitChildren (package:flutter/src/widgets/framework.dart:3676:14)
I/flutter (28527): #16     _InactiveElements._unmount (package:flutter/src/widgets/framework.dart:1693:13)
I/flutter (28527): #17     ListIterable.forEach (dart:_internal/iterable.dart:39:13)
I/flutter (28527): #18     _InactiveElements._unmountAll (package:flutter/src/widgets/framework.dart:1706:25)
I/flutter (28527): #19     BuildOwner.finalizeTree.<anonymous closure> (package:flutter/src/widgets/framework.dart:2328:27)
I/flutter (28527): #20     BuildOwner.lockState (package:flutter/src/widgets/framework.dart:2160:15)
I/flutter (28527): #21     BuildOwner.finalizeTree (package:flutter/src/widgets/framework.dart:2327:7)
I/flutter (28527): #22     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:628:18)
I/flutter (28527): #23     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:208:5)
I/flutter (28527): #24     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:990:15)
I/flutter (28527): #25     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:930:9)
I/flutter (28527): #26     _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:842:5)
I/flutter (28527): #27     _invoke (dart:ui/hooks.dart:120:13)
I/flutter (28527): #28     _drawFrame (dart:ui/hooks.dart:109:3)
I/flutter (28527): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter (28527): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3424 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.
I/flutter (28527): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3424 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.
I/flutter (28527): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3424 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.
I/flutter (28527): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3424 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.
I/flutter (28527): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3424 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.
I/flutter (28527): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3424 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.
I/flutter (28527): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3424 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.
I/flutter (28527): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3424 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.
I/flutter (28527): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3424 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.
I/flutter (28527): Another exception was thrown: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 3424 pos 12: '_debugLifecycleState != _ElementLifecycle.defunct': is not true.

build\app\outputs\apk\debug\app-debug.apk。
I/ActivityDelegate（28527）：恢复将当前活动设置为此
我/弗利特（28527）：肖像布局！！！！！！！！！！！！！！！！！！！！！！
I/hwaps（28527）：JNI_OnLoad
我/弗利特（28527）：景观布局！！！！！！！！！！！！！！！！！！！！！！
I/颤振（28527）：══╡ WIDGETS库捕获到异常╞═══════════════════════════════════════════════════════════
I/flatter（28527）：在完成小部件树时抛出以下断言：
I/flatter（28527）：当小部件树被锁定时调用setState（）或markNeedsBuild（）。
I/flatter（28527）：这个_ModalScope小部件不能被标记为需要构建，因为框架是
I/颤振（28527）：锁定。
I/flatter（28527）：调用setState（）或markNeedsBuild（）的小部件是：
I/颤振（28527）：_ModalScope-[LabeledGlobalKey#e1f0f]（状态：
I/颤振（28527）：_模态镜状态#830e3）
I/颤振（28527）：
I/flatter（28527）：抛出异常时，这是堆栈：
I/颤振（28527）：#0元素。markNeedsBuild。）

这是我的密码：

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'demo',
      theme: new ThemeData(primarySwatch: Colors.blue),
      home: new Home(),
    );
  }
}

class Home extends StatefulWidget {
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {
  static const int SCREEN_WIDTH_MIN = 600;

  @override
  Widget build(BuildContext context) {
    Widget _homelayout;
    var screenWidth = MediaQuery.of(context).size.width;
    var screenOrientation = MediaQuery.of(context).orientation;
    if ((screenWidth > SCREEN_WIDTH_MIN) &&
        (screenOrientation == Orientation.landscape)) {
      print('LANDSCAPE LAYOUT!!!!!!!!!!!!!!!!!!!!!!');
      //_homelayout = _buildLandscapeLayout(context);
      _homelayout = _buildLandscapeLayout();
    } else {
      print('PORTRAIT LAYOUT!!!!!!!!!!!!!!!!!!!!!!');
      _homelayout = _buildPortraitLayout();
    }
    return _homelayout;
  }

  Widget _buildPortraitLayout() {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('demo'),
      ),
      drawer: new DeviceListDrawer(),
      body: new Center(
        child: new Text('body'),
      ),
    );
  }
}

Widget _buildLandscapeLayout() {
  return new Scaffold(
    appBar: new AppBar(
      title: new Text('demo'),
    ),
    body: new Center(
      child: new Row(
        children: <Widget>[
          new DeviceListDrawer(),
          new Text('body')
        ],
      ),
    ),
  );
}

class DeviceListDrawer extends StatefulWidget {
  @override
  _DeviceListDrawerState createState() => _DeviceListDrawerState();
}

class _DeviceListDrawerState extends State<DeviceListDrawer> {
  @override
  Widget build(BuildContext context) {
    return new Container(
      width: 200.0,
      color: Colors.white,
      child: Column(
        children: <Widget>[
          new Container(
            width: 200.0,
            color: Colors.blue,
            padding: new EdgeInsets.only(
                top: MediaQuery.of(context).padding.top + 16.0, bottom: 16.0),
            child: new Text('demo '),
          ),
          new Expanded(
            child: new ListView(
              children: <Widget>[
                new Text('item 1'),
                new Text('item 2'),
                new Text('item 3'),
              ],
            ),
          ),
          new RaisedButton(
            child: new Text('add item'),
            onPressed: () {},
          )
        ],
      ),
    );
  }
}

导入“包装：颤振/材料.省道”；
void main（）=>runApp（新的MyApp（））；
类MyApp扩展了StatefulWidget{
@凌驾
_MyAppState createState（）=>\u MyAppState（）；
}
类MyAppState扩展了状态{
@凌驾
小部件构建（构建上下文）{
返回新材料PP(
标题：“演示”，
主题：新主题数据（原始样本：颜色。蓝色），
家：新家（），
);
}
}
类Home扩展了StatefulWidget{
@凌驾
_HomeState createState（）=>\u HomeState（）；
}
类(HomeState扩展状态){
静态常数int屏幕宽度最小值=600；
@凌驾
小部件构建（构建上下文）{
小部件(家庭布局),；
var screenWidth=MediaQuery.of（context）.size.width；
var screenOrientation=MediaQuery.of（context.orientation）；
如果（（屏幕宽度>屏幕宽度\u最小值）&&
（屏幕方向==方向.横向）{
打印（‘景观布局’！！！！！！！！！！！！！！！！！！！！！！！！！！！！！）；
//_homelayout=\u建筑景观布局（上下文）；
_homelayout=_buildLandscapeLayout（）；
}否则{
打印（'肖像布局！！！！！！！！！！！！！！！！！！！！！！！！！！！'）；
_homelayout=_buildLayout（）；
}
返回主页布局；
}
小部件_buildlayout（）{
归还新脚手架(
appBar：新的appBar(
标题：新文本（“演示”），
),
抽屉：新设备列表抽屉（），
正文：新中心(
子项：新文本（“正文”），
),
);
}
}
小部件_buildLandscapeLayout（）{
归还新脚手架(
appBar：新的appBar(
标题：新文本（“演示”），
),
正文：新中心(
孩子：新的一排(
儿童：[
新的DeviceListDrawer（），
新文本（“正文”）
],
),
),
);
}
类DeviceListDrawer扩展StatefulWidget{
@凌驾
_DeviceListDrawersState createState（）=>\u DeviceListDrawerState（）；
}
类_DeviceListDrawersState扩展状态{
@凌驾
小部件构建（构建上下文）{
退回新货柜(
宽度：200.0，
颜色：颜色，白色，
子：列(
儿童：[
新容器(
宽度：200.0，
颜色：颜色，蓝色，
填充：仅限新边设置(
顶部：MediaQuery.of（context.padding.top+16.0，底部：16.0），
子项：新文本（“演示”），
),
新扩展(
子：新列表视图(
儿童：[
新案文（“第1项”），
新案文（“第2项”），
新案文（“第3项”），
],
),
),
新升起的按钮(
子项：新文本（“添加项”），
按下：（）{}，
)
],
),
);
}
}

你能指出是什么问题吗？我怎样才能做出一个动态的布局？谢谢你的帮助。
你可以试试

Navigator.pop（上下文，true）

而不是

Navigator.pop（）
这通常发生在您已经处于新视图（在您的案例中为横向模式）并在已经消失的纵向模式上调用setState时。在进入横向模式之前，您应该以编程方式关闭抽屉。我同意您的看法。在_HomeState的构建方法开始时，我尝试用Navigator.pop（）关闭抽屉，但它不起作用。我知道应该把抽屉关在哪里吗？谢谢
void rebuild(BuildContext context) {
  Navigator.pop(context);
  setState(() {});
}