Issue 1:
The class AnimatedBuilder should have its name replaced. As it is not related to animation in reality.

For example, the following is possible :

final valueNotifier = ValueNotifier(0);

AnimatedBuilder(
animation: valueNotifier,
builder: (context, _) {
return Text(valueNotifier.value.toString());
},
)

Same goes for ScrollController, ...

I suggest to rename it to ListenableBuilder as it makes more sense.

Issue 2:
hi, i have met the problem when i run the lib/main.dart, the below is crash log

Flutter crash report; please file at https://github.com/flutter/flutter/issues.

command

flutter run

exception

FormatException: FormatException: Bad UTF-8 encoding 0xc3 (at offset 126)

#0 _Utf8Decoder.convert (dart:convert/utf.dart:484:15)
#1 _Utf8ConversionSink.addSlice (dart:convert/string_conversion.dart:345:14)
#2 _Utf8ConversionSink.add (dart:convert/string_conversion.dart:341:5)
#3 _ConverterStreamEventSink.add (dart:convert/chunked_conversion.dart:86:18)
#4 _SinkTransformerStreamSubscription._handleData (dart:async/stream_transformers.dart:120:24)
#5 _rootRunUnary (dart:async/zone.dart:1132:38)
#6 _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#7 _CustomZone.runUnaryGuarded (dart:async/zone.dart:931:7)
#8 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:336:11)
#9 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:263:7)
#10 _SyncStreamController._sendData (dart:async/stream_controller.dart:763:19)
#11 _StreamController._add (dart:async/stream_controller.dart:639:7)
#12 _StreamController.add (dart:async/stream_controller.dart:585:5)
#13 _Socket._onData (dart:io/runtime/binsocket_patch.dart:1721:41)
#14 _rootRunUnary (dart:async/zone.dart:1136:13)
#15 _CustomZone.runUnary (dart:async/zone.dart:1029:19)
#16 _CustomZone.runUnaryGuarded (dart:async/zone.dart:931:7)
#17 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:336:11)
#18 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:263:7)
#19 _SyncStreamController._sendData (dart:async/stream_controller.dart:763:19)
#20 _StreamController._add (dart:async/stream_controller.dart:639:7)
#21 _StreamController.add (dart:async/stream_controller.dart:585:5)
#22 new _RawSocket.<anonymous closure> (dart:io/runtime/binsocket_patch.dart:1283:33)
#23 _NativeSocket.issueReadEvent.issue (dart:io/runtime/binsocket_patch.dart:826:14)
#24 _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
#25 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)
#26 _runPendingImmediateCallback (dart:isolate/runtime/libisolate_patch.dart:115:13)
#27 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:172:5)

flutter doctor

�[32m[✓]�[39m Flutter (Channel stable, v1.0.0, on Microsoft Windows [Version 10.0.17134.471], locale zh-CN)
�[32m•�[39m Flutter version 1.0.0 at C:\flutter
�[32m•�[39m Framework revision 5391447fae (2 weeks ago), 2018-11-29 19:41:26 -0800
�[32m•�[39m Engine revision 7375a0f414
�[32m•�[39m Dart version 2.1.0 (build 2.1.0-dev.9.4 f9ebf21297)

�[32m[✓]�[39m Android toolchain - develop for Android devices (Android SDK 28.0.3)
�[32m•�[39m Android SDK at D:\AndroidSdk
�[32m•�[39m Android NDK location not configured (optional; useful for native profiling support)
�[32m•�[39m Platform android-28, build-tools 28.0.3
�[32m•�[39m Java binary at: D:\DevelopSoftware\Android Studio\jre\bin\java
�[32m•�[39m Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)
�[32m•�[39m All Android licenses accepted.

�[32m[✓]�[39m Android Studio (version 3.2)
�[32m•�[39m Android Studio at D:\DevelopSoftware\Android Studio
�[32m•�[39m Flutter plugin version 31.2.1
�[32m•�[39m Dart plugin version 181.5656
�[32m•�[39m Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)

�[32m[✓]�[39m IntelliJ IDEA Ultimate Edition (version 2018.3)
�[32m•�[39m IntelliJ at C:\Program Files\JetBrains\IntelliJ IDEA 2018.3
�[32m•�[39m Flutter plugin version 31.2.4
�[32m•�[39m Dart plugin version 183.4733

�[32m[✓]�[39m Connected device (1 available)
�[32m•�[39m BKL AL20 • P7C0218109001735 • android-arm64 • Android 8.0.0 (API 26)

�[32m•�[39m No issues found!