Flutter: Mystery padding above keyboard when TimeDilation > 1.0 - flutter

Question

I have a mystery padding above the keyboard when TimeDilation > 1.0 and I come to the screen with my keyboard on, from another screen.
Screenshot
The padding seems to be proportional to the time dilation when timeDilation >1.0 and < 3.0. It seems to be constant at the same height for timeDilation values >= 3.0.
If I change the routing so that FirstScreen never gets generated, the bug is avoided. Similarly, the bug can be worked around by forcing a screen redraw.
What is the cause and how do I need to change my code, to fix this bug?
MRTC:
import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart' show timeDilation;
import 'package:keyboard_actions/keyboard_actions.dart';
void main() async {
// set the system top-level property [timeDilation] to control the animation speed
timeDilation = 3.0;
WidgetsFlutterBinding.ensureInitialized();
runApp(
MyApp(),
);
}
class MyApp extends StatefulWidget {
MyApp({Key? key}) : super(key: key);
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
#override
Widget build(BuildContext context) {
return MaterialApp(
initialRoute: '/',
onGenerateRoute: (RouteSettings settings) {
final routes = <String, WidgetBuilder?>{
'/': (_) => FirstScreen(),
'/screen2': (_) => SecondScreen(),
};
final builder = routes[settings.name]!;
return MaterialPageRoute(
builder: builder,
settings: settings,
);
},
);
}
}
// ----------------------------------------------------------
class FirstScreen extends StatefulWidget {
FirstScreen({Key? key}) : super(key: key);
#override
_FirstScreenState createState() => _FirstScreenState();
}
class _FirstScreenState extends State<FirstScreen> {
#override
void initState() {
WidgetsBinding.instance?.addPostFrameCallback((_) {
Navigator.of(context).pushNamed('/screen2');
});
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold();
}
}
// ----------------------------------------------------------
class SecondScreen extends StatefulWidget {
#override
_SecondScreenState createState() => _SecondScreenState();
}
class _SecondScreenState extends State<SecondScreen>
with RouteAware, WidgetsBindingObserver {
FocusNode? focusNode;
ValueNotifier<String>? _stringValueNotifier;
#override
void initState() {
super.initState();
WidgetsBinding.instance!.addObserver(this);
this._stringValueNotifier = ValueNotifier<String>('');
this._stringValueNotifier!.addListener(() {});
}
#override
void dispose() {
_stringValueNotifier?.dispose();
WidgetsBinding.instance!.removeObserver(this);
super.dispose();
}
#override
Widget build(BuildContext context) {
this.focusNode = FocusNode();
return Scaffold(
body: KeyboardContent(
focusNode: this.focusNode!,
stringValueNotifier: this._stringValueNotifier!,
),
);
}
}
// ----------------------------------------------------------
class KeyboardContent extends StatelessWidget {
final FocusNode focusNode;
final ValueNotifier<String> stringValueNotifier;
/// A container for an on-screen keyboard
/// The widget automatically gets rebuilt on value change, triggered
/// when a keyboard button is pressed.
KeyboardContent({
required this.focusNode,
required this.stringValueNotifier,
});
KeyboardActionsConfig _buildConfig(BuildContext context) {
List<Widget Function(FocusNode)> toolbarButtons = [];
return KeyboardActionsConfig(
keyboardActionsPlatform: KeyboardActionsPlatform.ALL,
keyboardBarColor: Colors.grey[200]!,
//nextFocus: false,
actions: [
KeyboardActionsItem(
focusNode: focusNode,
displayActionBar: false,
displayDoneButton: false,
toolbarButtons: toolbarButtons,
footerBuilder: (_) => CueKeyboard(),
)
]);
}
#override
Widget build(BuildContext context) {
if (!focusNode.hasPrimaryFocus) focusNode.requestFocus();
return Container(
decoration: BoxDecoration(color: Colors.blue),
child: KeyboardActions(
config: _buildConfig(context),
child: Container(
padding: EdgeInsets.only(left: 15, right: 15),
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
KeyboardCustomInput<String>(
focusNode: focusNode,
notifier: stringValueNotifier,
builder: (context, keyboardTapVal, hasFocus) {
return Container(
margin: EdgeInsets.only(top: 100),
height: 800,
width: 100,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(32.0),
color: Colors.green));
},
),
],
),
),
),
);
}
}
class CueKeyboard extends StatefulWidget implements PreferredSizeWidget {
static final double _keyboardHeight = 184.0;
CueKeyboard({
Key? key,
}) : super(key: key);
#override
_CueKeyboardState createState() => _CueKeyboardState();
#override
Size get preferredSize => Size.fromHeight(CueKeyboard._keyboardHeight);
}
class _CueKeyboardState extends State<CueKeyboard> {
dispose() {
super.dispose();
}
#override
Widget build(BuildContext context) {
return Wrap(
children: [
Column(
children: [Text("Keyboard")],
),
],
);
}
}
flutter doctor
$ flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 2.8.1, on Microsoft Windows [Version 10.0.19044.1466], locale en-GB)
[√] Android toolchain - develop for Android devices (Android SDK version 32.0.0)
[√] Chrome - develop for the web
[√] Android Studio (version 2020.3)
[√] VS Code (version 1.63.2)
[√] Connected device (4 available)
• No issues found!
flutter run --verbose
$ flutter run --verbose
[ +53 ms] executing: [C:\flutter/] git -c log.showSignature=false log -n 1 --pretty=format:%H
[ +84 ms] Exit code 0 from: git -c log.showSignature=false log -n 1 --pretty=format:%H
[ ] 77d935af4db863f6abd0b9c31c7e6df2a13de57b
[ ] executing: [C:\flutter/] git tag --points-at 77d935af4db863f6abd0b9c31c7e6df2a13de57b
[ +24 ms] Exit code 0 from: git tag --points-at 77d935af4db863f6abd0b9c31c7e6df2a13de57b
[ ] 2.8.1
[ +6 ms] executing: [C:\flutter/] git rev-parse --abbrev-ref --symbolic #{u}
[ +15 ms] Exit code 0 from: git rev-parse --abbrev-ref --symbolic #{u}
[ ] origin/stable
[ ] executing: [C:\flutter/] git ls-remote --get-url origin
[ +11 ms] Exit code 0 from: git ls-remote --get-url origin
[ ] https://github.com/flutter/flutter.git
[ +70 ms] executing: [C:\flutter/] git rev-parse --abbrev-ref HEAD
[ +14 ms] Exit code 0 from: git rev-parse --abbrev-ref HEAD
[ ] stable
[ +47 ms] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'FlutterWebSdk' is not required, skipping update.
[ +7 ms] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'WindowsUwpEngineArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
[ +48 ms] executing: C:\Users\md844\Android\SDK\platform-tools\adb.exe devices -l
[ +40 ms] List of devices attached
emulator-5554 device product:sdk_phone_x86 model:Android_SDK_built_for_x86 device:generic_x86 transport_id:11
[ +6 ms] C:\Users\md844\Android\SDK\platform-tools\adb.exe -s emulator-5554 shell getprop
[ +33 ms] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping update.
[ +2 ms] Artifact Instance of 'WindowsEngineArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'WindowsUwpEngineArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required, skipping update.
[ ] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required, skipping update.
[ +66 ms] Skipping pub get: version match.
[ +40 ms] Found plugin integration_test at C:\flutter\packages\integration_test\
[ +82 ms] Found plugin integration_test at C:\flutter\packages\integration_test\
[ +6 ms] Generating C:\Users\md844\source\repos\ucue_keyboard_bug\android\app\src\main\java\io\flutter\plugins\GeneratedPluginRegistrant.java
[ +41 ms] ro.hardware = ranchu
[ +13 ms] Using hardware rendering with device Android SDK built for x86. If you notice graphics artifacts, consider enabling software rendering with
"--enable-software-rendering".
[ +24 ms] Initializing file store
[ +9 ms] Skipping target: gen_localizations
[ +4 ms] gen_dart_plugin_registrant: Starting due to {InvalidatedReasonKind.inputChanged: The following inputs have updated contents:
C:\Users\md844\source\repos\ucue_keyboard_bug\.dart_tool\package_config_subset}
[ +23 ms] Found plugin integration_test at C:\flutter\packages\integration_test\
[ +2 ms] gen_dart_plugin_registrant: Complete
[ +1 ms] Skipping target: _composite
[ +2 ms] complete
[ +4 ms] Launching lib\main.dart on Android SDK built for x86 in debug mode...
[ +3 ms] C:\flutter\bin\cache\dart-sdk\bin\dart.exe --disable-dart-dev C:\flutter\bin\cache\artifacts\engine\windows-x64\frontend_server.dart.snapshot --sdk-root
C:\flutter\bin\cache\artifacts\engine\common\flutter_patched_sdk/ --incremental --target=flutter --debugger-module-names --experimental-emit-debug-metadata
-DFLUTTER_WEB_AUTO_DETECT=true --output-dill C:\Users\md844\AppData\Local\Temp\flutter_tools.f728f2b7\flutter_tool.9d976d\app.dill --packages
C:\Users\md844\source\repos\ucue_keyboard_bug\.dart_tool\package_config.json -Ddart.vm.profile=false -Ddart.vm.product=false --enable-asserts --track-widget-creation
--filesystem-scheme org-dartlang-root --initialize-from-dill build\c075001b96339384a97db4862b8ab8db.cache.dill.track.dill --enable-experiment=alternative-invalidation-strategy
[ +7 ms] executing: C:\Users\md844\Android\SDK\build-tools\32.0.0\aapt dump xmltree C:\Users\md844\source\repos\ucue_keyboard_bug\build\app\outputs\flutter-apk\app.apk
AndroidManifest.xml
[ +8 ms] Exit code 0 from: C:\Users\md844\Android\SDK\build-tools\32.0.0\aapt dump xmltree C:\Users\md844\source\repos\ucue_keyboard_bug\build\app\outputs\flutter-apk\app.apk
AndroidManifest.xml
[ ] N: android=http://schemas.android.com/apk/res/android
E: manifest (line=2)
A: android:versionCode(0x0101021b)=(type 0x10)0x1
A: android:versionName(0x0101021c)="0.0.1" (Raw: "0.0.1")
A: android:compileSdkVersion(0x01010572)=(type 0x10)0x1d
A: android:compileSdkVersionCodename(0x01010573)="10" (Raw: "10")
A: package="uk.co.cuedspeech.ucue.debug" (Raw: "uk.co.cuedspeech.ucue.debug")
A: platformBuildVersionCode=(type 0x10)0x1d
A: platformBuildVersionName=(type 0x10)0xa
E: uses-sdk (line=7)
A: android:minSdkVersion(0x0101020c)=(type 0x10)0x17
A: android:targetSdkVersion(0x01010270)=(type 0x10)0x1e
E: uses-permission (line=14)
A: android:name(0x01010003)="android.permission.INTERNET" (Raw: "android.permission.INTERNET")
E: application (line=22)
A: android:label(0x01010001)="uCUE" (Raw: "uCUE")
A: android:icon(0x01010002)=#0x7f080000
A: android:name(0x01010003)="io.flutter.app.FlutterApplication" (Raw: "io.flutter.app.FlutterApplication")
A: android:debuggable(0x0101000f)=(type 0x12)0xffffffff
A: android:extractNativeLibs(0x010104ea)=(type 0x12)0x0
A: android:appComponentFactory(0x0101057a)="androidx.core.app.CoreComponentFactory" (Raw: "androidx.core.app.CoreComponentFactory")
E: activity (line=29)
A: android:theme(0x01010000)=#0x7f0a0000
A: android:name(0x01010003)="uk.co.cuedspeech.ucue.MainActivity" (Raw: "uk.co.cuedspeech.ucue.MainActivity")
A: android:launchMode(0x0101001d)=(type 0x10)0x1
A: android:configChanges(0x0101001f)=(type 0x11)0x40003fb4
A: android:windowSoftInputMode(0x0101022b)=(type 0x11)0x10
A: android:hardwareAccelerated(0x010102d3)=(type 0x12)0xffffffff
E: meta-data (line=43)
A: android:name(0x01010003)="io.flutter.embedding.android.NormalTheme" (Raw: "io.flutter.embedding.android.NormalTheme")
A: android:resource(0x01010025)=#0x7f0a0001
E: meta-data (line=53)
A: android:name(0x01010003)="io.flutter.embedding.android.SplashScreenDrawable" (Raw: "io.flutter.embedding.android.SplashScreenDrawable")
A: android:resource(0x01010025)=#0x7f040002
E: intent-filter (line=57)
E: action (line=58)
A: android:name(0x01010003)="android.intent.action.MAIN" (Raw: "android.intent.action.MAIN")
E: category (line=60)
A: android:name(0x01010003)="android.intent.category.LAUNCHER" (Raw: "android.intent.category.LAUNCHER")
E: meta-data (line=67)
A: android:name(0x01010003)="flutterEmbedding" (Raw: "flutterEmbedding")
A: android:value(0x01010024)=(type 0x10)0x2
[ +8 ms] executing: C:\Users\md844\Android\SDK\platform-tools\adb.exe -s emulator-5554 shell -x logcat -v time -t 1
[ +13 ms] <- compile package:ucue_keyboard_bug/main.dart
[ +55 ms] --------- beginning of main
[...]
[ +49 ms] --------- beginning of main
01-30 13:39:27.586 I/cmd (25596): oneway function results will be dropped but finished with status OK and parcel size 4
[ +6 ms] executing: C:\Users\md844\Android\SDK\platform-tools\adb.exe -s emulator-5554 shell am start -a android.intent.action.RUN -f 0x20000000 --ez
enable-background-compilation true --ez enable-dart-profiling true --ez enable-checked-mode true --ez verify-entry-points true
uk.co.cuedspeech.ucue.debug/uk.co.cuedspeech.ucue.MainActivity
[ +34 ms] Starting: Intent { act=android.intent.action.RUN flg=0x20000000 cmp=uk.co.cuedspeech.ucue.debug/uk.co.cuedspeech.ucue.MainActivity (has extras) }
[ +1 ms] Waiting for observatory port to be available...
[ +360 ms] W/FlutterActivityAndFragmentDelegate(25618): A splash screen was provided to Flutter, but this is deprecated. See flutter.dev/go/android-splash-migration for migration
steps.
[ +21 ms] Observatory URL on device: http://127.0.0.1:39329/Bg_xE12sSvQ=/
[ ] executing: C:\Users\md844\Android\SDK\platform-tools\adb.exe -s emulator-5554 forward tcp:0 tcp:39329
[ +16 ms] 60159
[ ] Forwarded host port 60159 to device port 39329 for Observatory
[ +4 ms] Caching compiled dill
[ +24 ms] Connecting to service protocol: http://127.0.0.1:60159/Bg_xE12sSvQ=/
[ +252 ms] Launching a Dart Developer Service (DDS) instance at http://127.0.0.1:0, connecting to VM service at http://127.0.0.1:60159/Bg_xE12sSvQ=/.
[ +116 ms] DDS is listening at http://127.0.0.1:60162/57G22rjDLdI=/.
[ +43 ms] Successfully connected to service protocol: http://127.0.0.1:60159/Bg_xE12sSvQ=/
[ +56 ms] DevFS: Creating new filesystem on the device (null)
[ +32 ms] DevFS: Created new filesystem on the device (file:///data/user/0/uk.co.cuedspeech.ucue.debug/code_cache/ucue_keyboard_bugULKJZB/ucue_keyboard_bug/)
[ +2 ms] Updating assets
[ +67 ms] Syncing files to device Android SDK built for x86...
[ +1 ms] <- reset
[ ] Compiling dart to kernel with 0 updated files
[ +2 ms] <- recompile package:ucue_keyboard_bug/main.dart 027f4494-050d-4ec8-becc-6f960203b371
[ ] <- 027f4494-050d-4ec8-becc-6f960203b371
[ +114 ms] Updating files.
[ ] DevFS: Sync finished
[ ] Syncing files to device Android SDK built for x86... (completed in 120ms)
[ ] Synced 0.0MB.
[ +1 ms] <- accept
[ +3 ms] Connected to _flutterView/0xe290b860.
[ +2 ms] Flutter run key commands.
[ +1 ms] r Hot reload.
[ ] R Hot restart.
[ ] h List all available interactive commands.
[ ] d Detach (terminate "flutter run" but leave application running).
[ ] c Clear the screen
[ ] q Quit (terminate the application on the device).
[ ] Running with sound null safety
[ ] An Observatory debugger and profiler on Android SDK built for x86 is available at: http://127.0.0.1:60162/57G22rjDLdI=/
[ +491 ms] I/eech.ucue.debu(25618): Waiting for a blocking GC ProfileSaver
[ +242 ms] The Flutter DevTools debugger and profiler on Android SDK built for x86 is available at: http://127.0.0.1:9101?uri=http://127.0.0.1:60162/57G22rjDLdI=/
pubspec.yaml
name: ucue_keyboard_bug
description: Demo app showing the keyboard bug when time dialation=3
publish_to: 'none' # Remove this line if you wish to publish to pub.dev
version: 0.0.1+1
environment:
sdk: '>=2.12.0-0 <3.0.0'
dependencies:
flutter:
sdk: flutter
flutter_localizations:
sdk: flutter
keyboard_actions: ^3.4.0
pedantic:
uuid: ^3.0.1
# Temporary dependencies
dependency_overrides:
dev_dependencies:
flutter_test:
sdk: flutter
integration_test:
sdk: flutter
analyzer:
strong-mode: true
language:
enableSuperMixins: true
# The following section is specific to Flutter.
flutter:
uses-material-design: true