LateInitializationError in a simple Flutter's hello world code

Question

There is following code:

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}
class MyApp extends StatelessWidget {
  const MyApp();
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
          Text("Hello world")
        ]
    );
  }
}

Whenever trying to run this code, there is an error:

════════ Exception caught by widgets library ═══════════════════════════════════════════════════════
LateInitializationError: _renderObject@20042623
...
E/flutter (14923): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: 'package:flutter/src/widgets/framework.dart': Failed assertion: line 2734 pos 20: '_debugCurrentBuildTarget == context': is not true.
E/flutter (14923): #0      _AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:46:39)
E/flutter (14923): #1      _AssertionError._throwNew (dart:core-patch/errors_patch.dart:36:5)
E/flutter (14923): #2      BuildOwner.buildScope. (package:flutter/src/widgets/framework.dart:2734:20)
E/flutter (14923): #3      BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2738:12)
E/flutter (14923): #4      RenderObjectToWidgetAdapter.attachToRenderTree (package:flutter/src/widgets/binding.dart:1127:13)
E/flutter (14923): #5      WidgetsBinding.attachRootWidget (package:flutter/src/widgets/binding.dart:967:7)
E/flutter (14923): #6      WidgetsBinding.scheduleAttachRootWidget. (package:flutter/src/widgets/binding.dart:948:7)
E/flutter (14923): #7      _rootRun (dart:async/zone.dart:1182:47)
E/flutter (14923): #8      _CustomZone.run (dart:async/zone.dart:1093:19)
E/flutter (14923): #9      _CustomZone.runGuarded (dart:async/zone.dart:997:7)
E/flutter (14923): #10     _CustomZone.bindCallbackGuarded. (dart:async/zone.dart:1037:23)
E/flutter (14923): #11     _rootRun (dart:async/zone.dart:1190:13)
E/flutter (14923): #12     _CustomZone.run (dart:async/zone.dart:1093:19)
E/flutter (14923): #13     _CustomZone.bindCallback. (dart:async/zone.dart:1021:23)
E/flutter (14923): #14     Timer._createTimer. (dart:async-patch/timer_patch.dart:18:15)
E/flutter (14923): #15     _Timer._runTimers (dart:isolate-patch/timer_impl.dart:397:19)
E/flutter (14923): #16     _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:428:5)
E/flutter (14923): #17     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:168:12)
E/flutter (14923):

When the Text object is removed from the children of Column, then there is no problem. There is an option also to wrap the widgets with MaterialApp, but I was wondering why it doesn't work without that?

This is Dart 2.11.

user_14510989 · Answer

Not sure why this is the error you get but the text widget is missing a Directionality ancestor widget that specifies if the text is left to right or right to left (MaterialApp also provides this)

So wrap the column in a Directionality

And file an issue (if it doesnt exist yet) on the flutter git repo for getting such an non descriptive error message

user_6890493 · Answer

It is better to use ‍‍MaterialApp which provides the basic settings of the app for you:

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Training(),
    );
  }
}

class Training extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
        children: [
          Text("Hello world")
        ]
    );
  }
}

LateInitializationError in a simple Flutter's hello world code

2 Answers