在 Flutter iconButton 中点击 appBar 但错误来了
In Flutter iconButton is click in appBar but error is coming
我一直在尝试在 appBar 中单击 iconButton 时触发对话框，但出现错误
这个错误是持久性的。
我认为在 showDialog() 中传递的上下文有一些问题我不确定
导入 'package:flutter/material.dart'；
导入 'package:flutter_colorpicker/flutter_colorpicker.dart';
void main() => runApp(new MyApp());
class MyApp extends StatefulWidget {
## Heading ##
@override
State<StatefulWidget> createState() {
// TODO: implement createState
return _MyPortfolioState();
}
}
class _MyPortfolioState extends State<MyApp> {
MaterialColor primaryColor = Colors.blue;
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Portfolio',
theme: new ThemeData(
primarySwatch: primaryColor,
),
home: Scaffold(
appBar: AppBar(
title: Text("Dhruv Agarwal"),
textTheme: TextTheme(
display2: TextStyle(color: Color.fromARGB(1, 0, 0, 0))),
actions: <Widget>[
new IconButton(
icon: Icon(Icons.format_color_text),
tooltip: 'Change Color',
onPressed: () {
Color pickerColor = primaryColor;
changeColor(Color color) {
setState(() => primaryColor = color);
}
showDialog (
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: const Text('Pick a color!'),
content: SingleChildScrollView(
child: ColorPicker(
pickerColor: pickerColor,
onColorChanged: changeColor,
pickerAreaHeightPercent: 0.8,
),
),
actions: <Widget>[
FlatButton(
child: Text('Got it'),
onPressed: () {
setState(() => primaryColor = pickerColor);
Navigator.of(context).pop();
},
),
],
);
});
},
),
])));
}
}
//
//
重新加载时抛出异常，未找到 MaterialLocalizations。
Launching lib/main.dart on Redmi Note 5 Pro in debug mode...
Initializing gradle...
Resolving dependencies...
Gradle task 'assembleDebug'...
Built build/app/outputs/apk/debug/app-debug.apk.
Installing build/app/outputs/apk/app.apk...
I/zygote64(16669): Do partial code cache collection, code=28KB, data=20KB
I/zygote64(16669): After code cache collection, code=28KB, data=20KB
I/zygote64(16669): Increasing code cache capacity to 128KB
Syncing files to device Redmi Note 5 Pro...
I/flutter (16669): ══╡ EXCEPTION CAUGHT BY GESTURE ╞═══════════════════════════════════════════════════════════════════
I/flutter (16669): The following assertion was thrown while handling a gesture:
I/flutter (16669): No MaterialLocalizations found.
I/flutter (16669): MyApp widgets require MaterialLocalizations to be provided by a Localizations widget ancestor.
I/flutter (16669): Localizations are used to generate many different messages, labels,and abbreviations which are used
I/flutter (16669): by the material library.
I/flutter (16669): To introduce a MaterialLocalizations, either use a MaterialApp at the root of your application to
I/flutter (16669): include them automatically, or add a Localization widget with a MaterialLocalizations delegate.
I/flutter (16669): The specific widget that could not find a MaterialLocalizations ancestor was:
I/flutter (16669): MyApp
I/flutter (16669): The ancestors of this widget were:
I/flutter (16669): [root]
I/flutter (16669):
I/flutter (16669): When the exception was thrown, this was the stack:
I/flutter (16669): #0 debugCheckHasMaterialLocalizations.<anonymous closure> (package:flutter/src/material/debug.dart:124:7)
I/flutter (16669): #1 debugCheckHasMaterialLocalizations (package:flutter/src/material/debug.dart:127:4)
I/flutter (16669): #2 showDialog (package:flutter/src/material/dialog.dart:606:10)
I/flutter (16669): #3 MyApp.build.<anonymous closure> (file:///home/punisher/AndroidStudioProjects/first_app/portfolio/lib/main.dart:32:19)
I/flutter (16669): #4 _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:507:14)
I/flutter (16669): #5 _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:562:30)
I/flutter (16669): #6 GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:102:24)
I/flutter (16669): #7 TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:242:9)
I/flutter (16669): #8 TapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:204:7)
I/flutter (16669): #9 GestureArenaManager.sweep (package:flutter/src/gestures/arena.dart:156:27)
I/flutter (16669): #10 _WidgetsFlutterBinding&BindingBase&GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:147:20)
I/flutter (16669): #11 _WidgetsFlutterBinding&BindingBase&GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:121:22)
I/flutter (16669): #12 _WidgetsFlutterBinding&BindingBase&GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:101:7)
I/flutter (16669): #13 _WidgetsFlutterBinding&BindingBase&GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:64:7)
I/flutter (16669): #14 _WidgetsFlutterBinding&BindingBase&GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:48:7)
I/flutter (16669): #15 _invoke1 (dart:ui/hooks.dart:153:13)
I/flutter (16669): #16 _dispatchPointerDataPacket (dart:ui/hooks.dart:107:5)
I/flutter (16669):
I/flutter (16669): Handler: onTap
I/flutter (16669): Recognizer:
I/flutter (16669): TapGestureRecognizer#5070d(debugOwner: GestureDetector, state: ready, won arena, finalPosition:
I/flutter (16669): Offset(354.2, 64.0), sent tap down)
I/flutter (16669): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter (16669): Another exception was thrown: No MaterialLocalizations found.
树中的某些 Material 小部件需要设置本地化，因此不要 运行 直接从 StatefulWidget 中获取您的应用，而是将其包装在 MaterialApp 中。因此 MaterialApp 会将您的 Widget 作为其子项，而不是相反。
main() => runApp(
MaterialApp(
title: 'ColorPicker test',
home: MyApp(),
),
);
MaterialApp 将在小部件树中设置 MaterialLocalizations，其子项将能够使用它。
顺便说一下，您的代码将无法工作，因为 ColorPicker 从所有可能的颜色中进行选择，而 primarySwatch 只能是 MaterialColor。您可以使用 material 拾色器重试。我认为 this plugin also provides it, you can check this one too.
我一直在尝试在 appBar 中单击 iconButton 时触发对话框，但出现错误
这个错误是持久性的。
我认为在 showDialog() 中传递的上下文有一些问题我不确定 导入 'package:flutter/material.dart'； 导入 'package:flutter_colorpicker/flutter_colorpicker.dart';
void main() => runApp(new MyApp());
class MyApp extends StatefulWidget {
## Heading ##
@override
State<StatefulWidget> createState() {
// TODO: implement createState
return _MyPortfolioState();
}
}
class _MyPortfolioState extends State<MyApp> {
MaterialColor primaryColor = Colors.blue;
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Portfolio',
theme: new ThemeData(
primarySwatch: primaryColor,
),
home: Scaffold(
appBar: AppBar(
title: Text("Dhruv Agarwal"),
textTheme: TextTheme(
display2: TextStyle(color: Color.fromARGB(1, 0, 0, 0))),
actions: <Widget>[
new IconButton(
icon: Icon(Icons.format_color_text),
tooltip: 'Change Color',
onPressed: () {
Color pickerColor = primaryColor;
changeColor(Color color) {
setState(() => primaryColor = color);
}
showDialog (
context: context,
builder: (BuildContext context) {
return AlertDialog(
title: const Text('Pick a color!'),
content: SingleChildScrollView(
child: ColorPicker(
pickerColor: pickerColor,
onColorChanged: changeColor,
pickerAreaHeightPercent: 0.8,
),
),
actions: <Widget>[
FlatButton(
child: Text('Got it'),
onPressed: () {
setState(() => primaryColor = pickerColor);
Navigator.of(context).pop();
},
),
],
);
});
},
),
])));
}
}
//
//
重新加载时抛出异常，未找到 MaterialLocalizations。
Launching lib/main.dart on Redmi Note 5 Pro in debug mode...
Initializing gradle...
Resolving dependencies...
Gradle task 'assembleDebug'...
Built build/app/outputs/apk/debug/app-debug.apk.
Installing build/app/outputs/apk/app.apk...
I/zygote64(16669): Do partial code cache collection, code=28KB, data=20KB
I/zygote64(16669): After code cache collection, code=28KB, data=20KB
I/zygote64(16669): Increasing code cache capacity to 128KB
Syncing files to device Redmi Note 5 Pro...
I/flutter (16669): ══╡ EXCEPTION CAUGHT BY GESTURE ╞═══════════════════════════════════════════════════════════════════
I/flutter (16669): The following assertion was thrown while handling a gesture:
I/flutter (16669): No MaterialLocalizations found.
I/flutter (16669): MyApp widgets require MaterialLocalizations to be provided by a Localizations widget ancestor.
I/flutter (16669): Localizations are used to generate many different messages, labels,and abbreviations which are used
I/flutter (16669): by the material library.
I/flutter (16669): To introduce a MaterialLocalizations, either use a MaterialApp at the root of your application to
I/flutter (16669): include them automatically, or add a Localization widget with a MaterialLocalizations delegate.
I/flutter (16669): The specific widget that could not find a MaterialLocalizations ancestor was:
I/flutter (16669): MyApp
I/flutter (16669): The ancestors of this widget were:
I/flutter (16669): [root]
I/flutter (16669):
I/flutter (16669): When the exception was thrown, this was the stack:
I/flutter (16669): #0 debugCheckHasMaterialLocalizations.<anonymous closure> (package:flutter/src/material/debug.dart:124:7)
I/flutter (16669): #1 debugCheckHasMaterialLocalizations (package:flutter/src/material/debug.dart:127:4)
I/flutter (16669): #2 showDialog (package:flutter/src/material/dialog.dart:606:10)
I/flutter (16669): #3 MyApp.build.<anonymous closure> (file:///home/punisher/AndroidStudioProjects/first_app/portfolio/lib/main.dart:32:19)
I/flutter (16669): #4 _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:507:14)
I/flutter (16669): #5 _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:562:30)
I/flutter (16669): #6 GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:102:24)
I/flutter (16669): #7 TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:242:9)
I/flutter (16669): #8 TapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:204:7)
I/flutter (16669): #9 GestureArenaManager.sweep (package:flutter/src/gestures/arena.dart:156:27)
I/flutter (16669): #10 _WidgetsFlutterBinding&BindingBase&GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:147:20)
I/flutter (16669): #11 _WidgetsFlutterBinding&BindingBase&GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:121:22)
I/flutter (16669): #12 _WidgetsFlutterBinding&BindingBase&GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:101:7)
I/flutter (16669): #13 _WidgetsFlutterBinding&BindingBase&GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:64:7)
I/flutter (16669): #14 _WidgetsFlutterBinding&BindingBase&GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:48:7)
I/flutter (16669): #15 _invoke1 (dart:ui/hooks.dart:153:13)
I/flutter (16669): #16 _dispatchPointerDataPacket (dart:ui/hooks.dart:107:5)
I/flutter (16669):
I/flutter (16669): Handler: onTap
I/flutter (16669): Recognizer:
I/flutter (16669): TapGestureRecognizer#5070d(debugOwner: GestureDetector, state: ready, won arena, finalPosition:
I/flutter (16669): Offset(354.2, 64.0), sent tap down)
I/flutter (16669): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter (16669): Another exception was thrown: No MaterialLocalizations found.
树中的某些 Material 小部件需要设置本地化，因此不要 运行 直接从 StatefulWidget 中获取您的应用，而是将其包装在 MaterialApp 中。因此 MaterialApp 会将您的 Widget 作为其子项，而不是相反。
main() => runApp(
MaterialApp(
title: 'ColorPicker test',
home: MyApp(),
),
);
MaterialApp 将在小部件树中设置 MaterialLocalizations，其子项将能够使用它。
顺便说一下，您的代码将无法工作，因为 ColorPicker 从所有可能的颜色中进行选择，而 primarySwatch 只能是 MaterialColor。您可以使用 material 拾色器重试。我认为 this plugin also provides it, you can check this one too.