Я только начал изучать разработку приложений через Flutter. Я наткнулся на учебник по созданию простого приложения.
Моя задача - добавить appbar, и я сделал это:
import 'package:flutter/material.dart';
void main() {
runApp(MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text('Hello '),
),
),
));
}
Я ожидаю простую панель приложения с заголовком " Здравствуйте ".
Я получаю эту ошибку в консоли:
-I/flutter (17741): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (17741): The following assertion was thrown building MyApp:
I/flutter (17741): MediaQuery.of() called with a context that does not contain a MediaQuery.
I/flutter (17741): No MediaQuery ancestor could be found starting from the context that was passed to MediaQuery.of().
I/flutter (17741): This can happen because you do not have a WidgetsApp or MaterialApp widget (those widgets introduce
I/flutter (17741): a MediaQuery), or it can happen if the context you use comes from a widget above those widgets.
I/flutter (17741): The context used was:
I/flutter (17741): Scaffold
I/flutter (17741):
I/flutter (17741): The relevant error-causing widget was:
I/flutter (17741): MyApp file:///E:/Flutter/i_am_rich/lib/main.dart:3:23
I/flutter (17741):
I/flutter (17741): When the exception was thrown, this was the stack:
I/flutter (17741): #0 MediaQuery.of (package:flutter/src/widgets/media_query.dart:798:5)
I/flutter (17741): #1 ScaffoldState.didChangeDependencies (package:flutter/src/material/scaffold.dart:1993:50)
I/flutter (17741): #2 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4376:12)
I/flutter (17741): #3 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
I/flutter (17741): #4 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
I/flutter (17741): #5 Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
I/flutter (17741): #6 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
Reloaded 1 of 478 libraries in 437ms.
I/flutter (17741): #7 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
I/flutter (17741): #8 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2432:33)
I/flutter (17741): #9 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:773:20)
I/flutter (17741): #10 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:283:5)
I/flutter (17741): #11 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1102:15)
I/flutter (17741): #12 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1041:9)
I/flutter (17741): #13 SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:850:7)
I/flutter (17741): #15 _Timer._runTimers (dart:isolate-patch/timer_impl.dart:384:19)
I/flutter (17741): #16 _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:418:5)
I/flutter (17741): #17 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:174:12)
I/flutter (17741): (elided one frame from package dart:async-patch)
I/flutter (17741):
I/flutter (17741):
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Было бы здорово, если бы вы могли дать мне некоторое представление об этом.