Android 在BottomModalSheet小部件的颤振中找不到Scaffold错误，即使它是在Scaffold内部定义的_Android_Flutter_Dart

Android 在BottomModalSheet小部件的颤振中找不到Scaffold错误，即使它是在Scaffold内部定义的

android flutter dart

Android 在BottomModalSheet小部件的颤振中找不到Scaffold错误，即使它是在Scaffold内部定义的,android,flutter,dart,Android,Flutter,Dart,我试图为一个测试应用程序实现一个BottomModalSheet。但每次都会出现同样的错误，说脚手架没有找到。应用程序的代码如下所示。错误显示脚手架是由MaterialApp小部件实现的，因此我删除了MaterialApp小部件并尝试了，但再次出现相同的错误 import 'package:flutter/material.dart'; void main() => runApp(MyApp()); class MyApp extends StatelessWidget { //

我试图为一个测试应用程序实现一个BottomModalSheet。但每次都会出现同样的错误，说脚手架没有找到。应用程序的代码如下所示。错误显示脚手架是由MaterialApp小部件实现的，因此我删除了MaterialApp小部件并尝试了，但再次出现相同的错误

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return Scaffold(
      appBar: AppBar(
        title: Text("Hello,World"),
      ),
      body: Center(
        child: Container(
          height: 300,
          width: 400,
          child: Column(
            children: <Widget>[
              //Container(color: Colors.blue, child: Text("Hello,World")),
              Container(
                height:200,
                width:500,
                child: FlatButton(
                  onPressed: (){
                    print("I Was clicked");
                    var sheetController = showBottomSheet(
                        context: context,
                        builder: (context) => BottomSheetWidget());
                    sheetController.closed.then((value) {
                    });
                  },
                  child: Container(
                    color: Colors.red,
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}


class BottomSheetWidget extends StatefulWidget {
  const BottomSheetWidget({Key key}) : super(key: key);

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

class _BottomSheetWidgetState extends State<BottomSheetWidget> {
  @override
  Widget build(BuildContext context) {
    return Container(
      margin: const EdgeInsets.only(top: 5, left: 15, right: 15),
      height: 160,
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        mainAxisSize: MainAxisSize.max,
        children: <Widget>[
          Container(
            height: 125,
            decoration: BoxDecoration(
                color: Colors.white,
                borderRadius: BorderRadius.circular(15),
                boxShadow: [
                  BoxShadow(
                      blurRadius: 10, color: Colors.grey[300], spreadRadius: 5)
                ]),
            child: Column(
              children: <Widget>[
                Container(
                  height:200,
                  width: 500,
                  child:Text("This is bottom Sheet")
                ),
              ],
            ),
          )
        ],
      ),
    );
  }
}

错误日志如下所示：

Syncing files to device AOSP on IA Emulator...
Reloaded 1 of 478 libraries in 2,727ms.
I/flutter (31983): I Was clicked

════════ Exception caught by gesture ═══════════════════════════════════════════════════════════════
The following assertion was thrown while handling a gesture:
No Scaffold widget found.

MyHomePage widgets require a Scaffold widget ancestor.
The specific widget that could not find a Scaffold ancestor was: MyHomePage
  state: _MyHomePageState#d2d59
The ancestors of this widget were: 
  : MaterialApp
    state: _MaterialAppState#d6736
  : MyApp
  ...

Typically, the Scaffold widget is introduced by the MaterialApp or WidgetsApp widget at the top of your application widget tree.

When the exception was thrown, this was the stack: 
#0      debugCheckHasScaffold.<anonymous closure> (package:flutter/src/material/debug.dart:112:7)
#1      debugCheckHasScaffold (package:flutter/src/material/debug.dart:123:4)
#2      showBottomSheet (package:flutter/src/material/bottom_sheet.dart:534:10)
#3      _MyHomePageState.build.<anonymous closure> (package:flutter_app/main.dart:42:43)
#4      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:706:14)
...
Handler: "onTap"
Recognizer: TapGestureRecognizer#6c46a
  debugOwner: GestureDetector
  state: possible
  won arena
  finalPosition: Offset(169.5, 356.2)
  finalLocalPosition: Offset(163.8, 124.4)
  button: 1
  sent tap down
════════════════════════════════════════════════════════════════════════════════════════════════════

您可以复制粘贴运行下面的完整代码您可以使用var scaffoldKey.currentState.showBottomSheet

代码片段

final GlobalKey<ScaffoldState> scaffoldKey = GlobalKey<ScaffoldState>();

return Scaffold(
  key: scaffoldKey,

 ...

 onPressed: () {
                print("I Was clicked");
                var sheetController = scaffoldKey.currentState
                    .showBottomSheet((context) => BottomSheetWidget());
                sheetController.closed.then((value) {
                  print("closed");
                });
              },

工作演示

完整代码

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    final GlobalKey<ScaffoldState> scaffoldKey = GlobalKey<ScaffoldState>();

    return Scaffold(
      key: scaffoldKey,
      appBar: AppBar(
        title: Text("Hello,World"),
      ),
      body: Center(
        child: Container(
          height: 300,
          width: 400,
          child: Column(
            children: <Widget>[
              //Container(color: Colors.blue, child: Text("Hello,World")),
              Container(
                height: 200,
                width: 500,
                child: FlatButton(
                  onPressed: () {
                    print("I Was clicked");
                    var sheetController = scaffoldKey.currentState
                        .showBottomSheet((context) => BottomSheetWidget());
                    sheetController.closed.then((value) {
                      print("closed");
                    });
                  },
                  child: Container(
                    color: Colors.red,
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class BottomSheetWidget extends StatefulWidget {
  const BottomSheetWidget({Key key}) : super(key: key);

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

class _BottomSheetWidgetState extends State<BottomSheetWidget> {
  @override
  Widget build(BuildContext context) {
    return Container(
      margin: const EdgeInsets.only(top: 5, left: 15, right: 15),
      height: 160,
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        mainAxisSize: MainAxisSize.max,
        children: <Widget>[
          Container(
            height: 125,
            decoration: BoxDecoration(
                color: Colors.white,
                borderRadius: BorderRadius.circular(15),
                boxShadow: [
                  BoxShadow(
                      blurRadius: 10, color: Colors.grey[300], spreadRadius: 5)
                ]),
            child: Column(
              children: <Widget>[
                Container(
                    height: 100,
                    width: 500,
                    child: Text("This is bottom Sheet")),
              ],
            ),
          )
        ],
      ),
    );
  }
}