在我们现在正在编写的应用程序中，我们遇到的问题是，如果将焦点放在底部工作表内的文本字段上，键盘会在短暂闪烁后消失。
经过数小时的尝试修复，我试图隔离这种奇怪的行为并提出以下错误：
如果我点击不是主页的页面支架底部的TextField，键盘就会消失。
我已经在https://github.com/flutter/flutter/issues/36271上发布了此内容，但未得到任何回复。
有人知道吗？真的是一个错误还是我在路线上做错了什么？
先谢谢您。 马库斯
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(
routes: {
'secondPage': (_) => SecondPage(),
},
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Home(),
);
}
}
class Home extends StatefulWidget {
@override
_HomeState createState() => _HomeState();
}
class _HomeState extends State<Home> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('it does work here'),
),
body: Center(
child: FlatButton(
onPressed: () => Navigator.of(context).pushNamed('secondPage'),
child: Container(
width: 123,
height: 23,
color: Colors.red,
child: Text(
'2nd Page',
textAlign: TextAlign.center,
),
)),
),
bottomSheet: Container(
width: double.infinity,
color: Colors.lightGreen,
height: 90,
child: Center(child: Container(width: 200, child: TextField())),
),
);
}
}
class SecondPage extends StatefulWidget {
SecondPage({Key key}) : super(key: key);
@override
_SecondPageState createState() => _SecondPageState();
}
class _SecondPageState extends State<SecondPage> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('it does not work here'),
),
bottomSheet: Container(
width: double.infinity,
color: Colors.lightGreen,
height: 90,
child: Center(child: Container(width: 200, child: TextField())),
),
);
}
}
在底部工作表中为容器提供全局密钥会强制键盘保持活动状态，但是随后Ios上的红色屏幕闪烁，并且出现以下错误：
I/flutter (15864): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (15864): The following assertion was thrown while finalizing the widget tree:
I/flutter (15864): Duplicate GlobalKey detected in widget tree.
I/flutter (15864): The following GlobalKey was specified multiple times in the widget tree. This will lead to parts of
I/flutter (15864): the widget tree being truncated unexpectedly, because the second time a key is seen, the previous
I/flutter (15864): instance is moved to the new location. The key was:
I/flutter (15864): - [GlobalKey#06a16]
I/flutter (15864): This was determined by noticing that after the widget with the above global key was moved out of its
I/flutter (15864): previous parent, that previous parent never updated during this frame, meaning that it either did
I/flutter (15864): not update at all or updated before the widget was moved, in either case implying that it still
I/flutter (15864): thinks that it should have a child with that global key.
I/flutter (15864): The specific parent that did not update after having one or more children forcibly removed due to
I/flutter (15864): GlobalKey reparenting is:
I/flutter (15864): - _InheritedResetNotifier
I/flutter (15864): A GlobalKey can only be specified on one widget at a time in the widget tree.
I/flutter (15864):
I/flutter (15864): When the exception was thrown, this was the stack:
I/flutter (15864): #0 BuildOwner.finalizeTree.<anonymous closure> (package:flutter/src/widgets/framework.dart:2485:15)
I/flutter (15864): #1 BuildOwner.finalizeTree (package:flutter/src/widgets/framework.dart:2510:8)
I/flutter (15864): #2 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:702:18)
I/flutter (15864): #3 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:285:5)
I/flutter (15864): #4 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1016:15)
I/flutter (15864): #5 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:958:9)
I/flutter (15864): #6 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:874:5)
I/flutter (15864): #10 _invoke (dart:ui/hooks.dart:236:10)
I/flutter (15864): #11 _drawFrame (dart:ui/hooks.dart:194:3)
I/flutter (15864): (elided 3 frames from package dart:async)
I/flutter (15864): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/HwSecImmHelper(15864): mSecurityInputMethodService is null
I/flutter (15864): Another exception was thrown: Duplicate GlobalKey detected in widget tree.
class SecondPage extends StatefulWidget {
SecondPage({Key key}) : super(key: key);
@override
_SecondPageState createState() => _SecondPageState();
}
class _SecondPageState extends State<SecondPage> {
static final Key _key = GlobalKey();
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('it does not work here'),
),
bottomSheet: Container(
key: _key,
width: double.infinity,
color: Colors.lightGreen,
height: 90,
child: Center(child: Container(width: 200, child: TextField())),
),
);
}
}
dynClient36:flutter_app mhein$ flutter doctor -v
[✓] Flutter (Channel stable, v1.7.8+hotfix.3, on Mac OS X 10.14.5 18F132, locale de-DE)
• Flutter version 1.7.8+hotfix.3 at /Users/mhein/Documents/flutter
• Framework revision b712a172f9 (8 days ago), 2019-07-09 13:14:38 -0700
• Engine revision 54ad777fd2
• Dart version 2.4.0
[✓] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
• Android SDK at /Users/mhein/Library/Android/sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-28, build-tools 28.0.3
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 10.2.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 10.2.1, Build version 10E1001
• CocoaPods version 1.7.0
[✓] iOS tools - develop for iOS devices
• ios-deploy 1.9.4
[✓] Android Studio (version 3.4)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin version 37.0.1
• Dart plugin version 183.6270
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b01)
[✓] VS Code (version 1.36.1)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.2.0
[✓] Connected device (2 available)
• ONEPLUS A6003 • 89a98b7a • android-arm64 • Android 9 (API 28)
• Android SDK built for x86 • emulator-5554 • android-x86 • Android 9 (API 28) (emulator)
• No issues found!
答案 0 :(得分：1)
一种魔术，但是当您保持底部状态时，它会起作用：
class _SecondPageState extends State<SecondPage> {
final _bottomSheet = Container(
color: Colors.lightGreen,
height: 90,
child: Center(child: Container(width: 200, child: TextField())),
);
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('it does not work here'),
),
bottomSheet: _bottomSheet,
);
}
}
当我注意到build激活时两次调用TextField方法时，我有了主意。
答案 1 :(得分：0)
您还可以将其包装成堆栈，然后使用“底部位置：0 ..”
答案 2 :(得分：0)
老实说，我从来没有找到正确的答案（花了 3 小时找出问题）所以这里是我发现的：
就像@Spatz 所说的那样，当键盘打开时，showModalBottomSheet 的整个子项都会重新绘制。因此，所有子小部件也将被重新绘制，其中包括 TextFormField。因为它是重新绘制的并且没有键，所以它会失去焦点并且键盘会关闭。
要解决此问题，我们只需将 ValueKey() 添加到 TextFormField(s) 中，一切都会按预期工作。
答案 3 :(得分：0)
这是一个错误，_formKey.currentState!.validate() 您必须为要提交验证的字段使用 Form(key: _formKey child: ..) 包装器。