flutter/samples

A collection of Flutter examples and demos

Flutter is Google's SDK for crafting beautiful, fast user experiences for mobile, web, and desktop from a single codebase. Flutter works with existing code, is used by developers and organizations around the world, and is free and open source.

Documentation

• Install Flutter
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• Development wiki
• Contributing to Flutter

For announcements about new releases, follow the [email protected] mailing list. Our documentation also tracks breaking changes across releases.

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The Flutter tool may occasionally download resources from Google servers. By downloading or using the Flutter SDK, you agree to the Google Terms of Service: https://policies.google.com/terms

For example, when installed from GitHub (as opposed to from a prepackaged archive), the Flutter tool will download the Dart SDK from Google servers immediately when first run, as it is used to execute the flutter tool itself. This will also occur when Flutter is upgraded (e.g. by running the flutter upgrade command).

About Flutter

We think Flutter will help you create beautiful, fast apps, with a productive, extensible and open development model, whether you're targeting iOS or Android, web, Windows, macOS, Linux or embedding it as the UI toolkit for a platform of your choice.

Beautiful user experiences

We want to enable designers to deliver their full creative vision without being forced to water it down due to limitations of the underlying framework. Flutter's layered architecture gives you control over every pixel on the screen and its powerful compositing capabilities let you overlay and animate graphics, video, text, and controls without limitation. Flutter includes a full set of widgets that deliver pixel-perfect experiences whether you're building for iOS (Cupertino) or other platforms (Material), along with support for customizing or creating entirely new visual components.

Fast results

Flutter is fast. It's powered by hardware-accelerated 2D graphics libraries like Skia (that underpins Chrome and Android) and Impeller. We architected Flutter to support glitch-free, jank-free graphics at the native speed of your device.

Flutter code is powered by the world-class Dart platform, which enables compilation to 32-bit and 64-bit ARM machine code for iOS and Android, JavaScript and WebAssembly for the web, as well as Intel x64 and ARM for desktop devices.

Productive development

Flutter offers stateful hot reload, allowing you to make changes to your code and see the results instantly without restarting your app or losing its state.

Extensible and open model

Flutter works with any development tool (or none at all), and also includes editor plug-ins for both Visual Studio Code and IntelliJ / Android Studio. Flutter provides tens of thousands of packages to speed your development, regardless of your target platform. And accessing other native code is easy, with support for both FFI (on Android, on iOS, on macOS, and on Windows) as well as platform-specific APIs.

Flutter is a fully open-source project, and we welcome contributions. Information on how to get started can be found in our contributor guide.

samples's Issues

[visual sample index] Clarify samples vs demos

This could be something simple like a tooltip, or an explanation on the page.

[Veggieseasons] Main feed shouldn't scroll behind status bar

See the iOS App Store. There's a static background bar behind the status bar as the feed is scrolled up.

doc bug: Missing samples in Experimental sample doc

doc bug: Missing samples in Experimental sample doc

Here is the index - https://github.com/flutter/samples/tree/master/experimental#index

We need to update this with desktop_photo_search and web_dashboard content as well.

sample repo for data persistence

@RedBrogdon can I add sample repo which shows how to use data persistence using SQFlite .

[visual sample index] Add Carousel

Design spec:

[animations] Update README.md

Description

The basic animation section in the app has two new examples, AnimatedPositioned and AnimatedSwitcher which hasn't been updated in the README.md.

Create continuous build/integration samples and documentation for add-to-app

We currently have https://flutter.dev/docs/deployment/cd and partners like CodeMagic for full-Flutter CI instructions but it's not clear how to do add-to-app CI. Create documentation and samples demonstrating add-to-app CI.

cc @RedBrogdon

Veggie Seasons UI doesn't handle dark mode well

Title says it all. We need to update the app to deal with iOS's dark mode properly rather than displaying black-on-black text in several places within the app.

[animations] Add AnimatedWidget sample - FadeTransition

Missing animation samples of various Animation widgets.

@RedBrogdon @johnpryan Do we plan to add samples of widget animations like FadeTransition, DecoratedBoxTransition, RotationTransition, etc.

If yes please do let me know. Would love to add samples for them here.

Animated Container overflows on right

Hi guys,

i am using a Animated Container to move some text from left to right.
Therefore I use a variable currentPositon and a positionPadding which ist 30.
So for the increasing currentPosition the container moves 30 points to the right. But my problem is, that there is no limit. As a result the container just overflows the right and i need it to stop before it overflows.

Thanks in advance

att3x

[veggieseasons] Android subproject should be removed.

On the details screen, when users tap the back button of the device, the app gets closed instead of navigating back to the home screen.
Back button should behave like the close button given in the header section of the details screen.

Windows build and run error.

I followed the instructions on https://flutter.dev/desktop and https://github.com/google/flutter-desktop-embedding/tree/master/example, and in the gallery directory, I run flutter run -d windows failed, the detailed logs are belows.

The full error log

D:\code\flutter\samples\gallery>flutter run -d windows -v
[  +23 ms] executing: [D:\apps\flutter/] git -c log.showSignature=false log -n 1
--pretty=format:%H
[ +109 ms] Exit code 0 from: git -c log.showSignature=false log -n 1
--pretty=format:%H
[   +2 ms] 1d3fcfd6ca7e83c6c7d134fc99deb015839b0389
[   +1 ms] executing: [D:\apps\flutter/] git describe --match v*.*.*
--first-parent --long --tags
[ +108 ms] Exit code 0 from: git describe --match v*.*.* --first-parent --long
--tags
[   +1 ms] v1.15.3-241-g1d3fcfd6c
[   +7 ms] executing: [D:\apps\flutter/] git rev-parse --abbrev-ref --symbolic
@{u}
[  +94 ms] Exit code 0 from: git rev-parse --abbrev-ref --symbolic @{u}
[   +1 ms] origin/master
[   +1 ms] executing: [D:\apps\flutter/] git ls-remote --get-url origin
[  +82 ms] Exit code 0 from: git ls-remote --get-url origin
[   +1 ms] https://github.com/flutter/flutter.git
[ +120 ms] executing: [D:\apps\flutter/] git rev-parse --abbrev-ref HEAD
[  +82 ms] Exit code 0 from: git rev-parse --abbrev-ref HEAD
[   +2 ms] master
[  +34 ms] Artifact Instance of 'AndroidMavenArtifacts' is not required,
skipping update.
[   +1 ms] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required,
skipping update.
[   +3 ms] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required,
skipping update.
[   +1 ms] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping
update.
[        ] Artifact Instance of 'FlutterWebSdk' is not required, skipping
update.
[   +4 ms] Artifact Instance of 'WindowsEngineArtifacts' is not required,
skipping update.
[   +1 ms] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping
update.
[   +3 ms] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping
update.
[   +1 ms] 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.
[  +22 ms] executing: D:\apps\android_sdk\platform-tools\adb.exe devices -l
[  +34 ms] Exit code 0 from: D:\apps\android_sdk\platform-tools\adb.exe devices
-l
[   +1 ms] List of devices attached
[  +13 ms] Artifact Instance of 'AndroidMavenArtifacts' is not required,
skipping update.
[   +4 ms] Artifact Instance of 'AndroidGenSnapshotArtifacts' is not required,
skipping update.
[   +1 ms] Artifact Instance of 'AndroidInternalBuildArtifacts' is not required,
skipping update.
[   +3 ms] Artifact Instance of 'IOSEngineArtifacts' is not required, skipping
update.
[   +1 ms] Artifact Instance of 'FlutterWebSdk' is not required, skipping
update.
[   +5 ms] Artifact Instance of 'MacOSEngineArtifacts' is not required, skipping
update.
[   +1 ms] Artifact Instance of 'LinuxEngineArtifacts' is not required, skipping
update.
[   +3 ms] Artifact Instance of 'LinuxFuchsiaSDKArtifacts' is not required,
skipping update.
[   +1 ms] Artifact Instance of 'MacOSFuchsiaSDKArtifacts' is not required,
skipping update.
[   +1 ms] Artifact Instance of 'FlutterRunnerSDKArtifacts' is not required,
skipping update.
[   +1 ms] Artifact Instance of 'FlutterRunnerDebugSymbols' is not required,
skipping update.
[ +112 ms] Found plugin package_info at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\package_info-0.4.0+14\
[   +8 ms] Found plugin path_provider at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\path_provider-1.6.1\
[  +11 ms] Found plugin shared_preferences at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\shared_preferences-0.5.6+2\
[   +2 ms] Found plugin shared_preferences_macos at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\shared_preferences_macos-0.0
.1+6\
[   +3 ms] Found plugin shared_preferences_web at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\shared_preferences_web-0.1.2
+4\
[   +9 ms] Found plugin url_launcher at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\url_launcher-5.4.2\
[   +2 ms] Found plugin url_launcher_macos at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\url_launcher_macos-0.0.1+4\
[   +4 ms] Found plugin url_launcher_web at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\url_launcher_web-0.1.1+1\
[ +666 ms] Found plugin package_info at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\package_info-0.4.0+14\
[   +4 ms] Found plugin path_provider at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\path_provider-1.6.1\
[   +6 ms] Found plugin shared_preferences at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\shared_preferences-0.5.6+2\
[   +2 ms] Found plugin shared_preferences_macos at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\shared_preferences_macos-0.0
.1+6\
[   +3 ms] Found plugin shared_preferences_web at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\shared_preferences_web-0.1.2
+4\
[   +6 ms] Found plugin url_launcher at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\url_launcher-5.4.2\
[   +2 ms] Found plugin url_launcher_macos at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\url_launcher_macos-0.0.1+4\
[   +2 ms] Found plugin url_launcher_web at
D:\apps\flutter\.pub-cache\hosted\pub.flutter-io.cn\url_launcher_web-0.1.1+1\
[  +37 ms] Generating
D:\code\flutter\samples\gallery\android\app\src\main\java\io\flutter\plugins\Gen
eratedPluginRegistrant.java
[  +94 ms] Launching lib\main.dart on Windows in debug mode...
[  +10 ms] D:\apps\flutter\bin\cache\dart-sdk\bin\dart.exe
D:\apps\flutter\bin\cache\artifacts\engine\windows-x64\frontend_server.dart.snap
shot --sdk-root
D:\apps\flutter\bin\cache\artifacts\engine\common\flutter_patched_sdk/
--incremental --target=flutter -Ddart.developer.causal_async_stacks=true
--output-dill
C:\Users\LIUD~1.H\AppData\Local\Temp\flutter_tool.ac84d8bd-5c75-11ea-9496-8c1645
895bf6\app.dill --packages D:\code\flutter\samples\gallery\.packages
-Ddart.vm.profile=false -Ddart.vm.product=false
--bytecode-options=source-positions,local-var-info,debugger-stops,instance-field
-initializers,keep-unreachable-code,avoid-closure-call-instructions
--enable-asserts --track-widget-creation --filesystem-scheme org-dartlang-root
[  +24 ms] executing: C:\Program Files (x86)\Microsoft Visual
Studio\Installer\vswhere.exe -format json -utf8 -latest -version 16 -requires
Microsoft.Component.MSBuild Microsoft.VisualStudio.Component.VC.Tools.x86.x64
Microsoft.VisualStudio.Component.Windows10SDK.17763
[  +34 ms] Exit code 0 from: C:\Program Files (x86)\Microsoft Visual
Studio\Installer\vswhere.exe -format json -utf8 -latest -version 16 -requires
Microsoft.Component.MSBuild Microsoft.VisualStudio.Component.VC.Tools.x86.x64
Microsoft.VisualStudio.Component.Windows10SDK.17763
[   +1 ms] [
             {
               "instanceId": "65672dd3",
               "installDate": "2019-05-10T05:41:26Z",
               "installationName": "VisualStudio/16.4.4+29728.190",
               "installationPath": "C:\\Program Files (x86)\\Microsoft Visual
               Studio\\2019\\Community",
               "installationVersion": "16.4.29728.190",
               "productId": "Microsoft.VisualStudio.Product.Community",
               "productPath": "C:\\Program Files (x86)\\Microsoft Visual
               Studio\\2019\\Community\\Common7\\IDE\\devenv.exe",
               "state": 4294967295,
               "isComplete": true,
               "isLaunchable": true,
               "isPrerelease": false,
               "isRebootRequired": false,
               "displayName": "Visual Studio Community 2019",
               "description": "Powerful IDE, free for students, open-source
               contributors, and individuals",
               "channelId": "VisualStudio.16.Release",
               "channelUri": "https://aka.ms/vs/16/release/channel",
               "enginePath": "C:\\Program Files (x86)\\Microsoft Visual
               Studio\\Installer\\resources\\app\\ServiceHub\\Services\\Microsof
               t.VisualStudio.Setup.Service",
               "releaseNotes":
               "https://go.microsoft.com/fwlink/?LinkId=660893#16.4.4",
               "thirdPartyNotices":
               "https://go.microsoft.com/fwlink/?LinkId=660909",
               "updateDate": "2020-02-07T04:54:52.6868595Z",
               "catalog": {
                 "buildBranch": "d16.4",
                 "buildVersion": "16.4.29728.190",
                 "id": "VisualStudio/16.4.4+29728.190",
                 "localBuild": "build-lab",
                 "manifestName": "VisualStudio",
                 "manifestType": "installer",
                 "productDisplayVersion": "16.4.4",
                 "productLine": "Dev16",
                 "productLineVersion": "2019",
                 "productMilestone": "RTW",
                 "productMilestoneIsPreRelease": "False",
                 "productName": "Visual Studio",
                 "productPatchVersion": "4",
                 "productPreReleaseMilestoneSuffix": "1.0",
                 "productSemanticVersion": "16.4.4+29728.190",
                 "requiredEngineVersion": "2.4.1111.43337"
               },
               "properties": {
                 "campaignId": "2127318680.1547124013",
                 "canceled": "0",
                 "channelManifestId":
                 "VisualStudio.16.Release/16.4.4+29728.190",
                 "nickname": "",
                 "setupEngineFilePath": "C:\\program files (x86)\\microsoft
                 visual studio\\installer\\vs_installershell.exe"
               }
             }
           ]
[   +5 ms] Building Windows application...
[   +2 ms] executing: [D:\code\flutter\samples\gallery\windows/]
D:\apps\flutter\packages\flutter_tools\bin\vs_build.bat C:\Program Files
(x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat
Runner.sln Debug
[  +11 ms] <- compile package:gallery/main.dart
[ +416 ms]
**********************************************************************
[   +5 ms] ** Visual Studio 2019 Developer Command Prompt v16.4.4
[   +1 ms] ** Copyright (c) 2019 Microsoft Corporation
[        ]
**********************************************************************
[+1348 ms]
                    Compiler message:
[   +4 ms] lib/pages/home.dart:1121:48: Error: Type
'WidgetOrderFocusTraversalPolicy' not
           found.
[   +3 ms] class StudyWrapperFocusTraversalPolicy extends
WidgetOrderFocusTraversalPolicy {
[   +2 ms]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[   +4 ms] lib/layout/focus_traversal_policy.dart:13:48: Error: Type
           'WidgetOrderFocusTraversalPolicy' not found.
[   +1 ms] class EdgeChildrenFocusTraversalPolicy extends
WidgetOrderFocusTraversalPolicy {
[   +3 ms]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[ +274 ms] [vcvarsall.bat] Environment initialized for: 'x64'
[ +111 ms] Microsoft (R) Build Engine version 16.4.0+e901037fe for .NET
Framework
[   +1 ms] Copyright (C) Microsoft Corporation. All rights reserved.
[        ] Building the projects in this solution one at a time. To enable
parallel build, please add the "-m" switch.
[  +48 ms] Build started 2020-03-02 19:05:11.
[ +151 ms] Project "D:\code\flutter\samples\gallery\windows\Runner.sln" on node
1 (default targets).
[   +7 ms] ValidateSolutionConfiguration:
[   +1 ms]   Building solution configuration "Debug|x64".
[ +228 ms] Project "D:\code\flutter\samples\gallery\windows\Runner.sln" (1) is
building "D:\code\flutter\samples\gallery\windows\Runner.vcxproj.metaproj" (2)
on node 1 (default targets).
[   +2 ms] Project
"D:\code\flutter\samples\gallery\windows\Runner.vcxproj.metaproj" (2) is
building "D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj" (3) on
node 1 (default targets).
[   +2 ms] InitializeBuildStatus:
[   +1 ms]   Touching "x64\Debug\Flutter Build.tlog\unsuccessfulbuild".
[  +18 ms] CustomBuildStep:
[   +1 ms]   Running Flutter backend build
[   +8 ms]
"D:\code\flutter\samples\gallery\windows\scripts\prepare_dependencies" Debug
[   +1 ms]   :VCEnd
[+1333 ms] lib/pages/backdrop.dart:216:14: Error: The method
'DefaultFocusTraversal' isn't
                    defined for the class '_BackdropState'.
[   +1 ms]  - '_BackdropState' is from 'package:gallery/pages/backdrop.dart'
            ('lib/pages/backdrop.dart').
[   +1 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'DefaultFocusTraversal'.
[   +2 ms]       child: DefaultFocusTraversal(
[   +1 ms]              ^^^^^^^^^^^^^^^^^^^^^
[   +1 ms] lib/pages/backdrop.dart:217:17: Error: The method
           'WidgetOrderFocusTraversalPolicy' isn't defined for the class
'_BackdropState'.
[   +1 ms]  - '_BackdropState' is from 'package:gallery/pages/backdrop.dart'
            ('lib/pages/backdrop.dart').
[   +3 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'WidgetOrderFocusTraversalPolicy'.
[   +1 ms]         policy: WidgetOrderFocusTraversalPolicy(),
[   +2 ms]                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[   +1 ms] lib/pages/backdrop.dart:230:12: Error: The method
'DefaultFocusTraversal' isn't
           defined for the class '_BackdropState'.
[   +1 ms]  - '_BackdropState' is from 'package:gallery/pages/backdrop.dart'
            ('lib/pages/backdrop.dart').
[   +2 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'DefaultFocusTraversal'.
[   +1 ms]     return DefaultFocusTraversal(
[   +2 ms]            ^^^^^^^^^^^^^^^^^^^^^
[ +688 ms] lib/pages/home.dart:413:16: Error: The method 'DefaultFocusTraversal'
isn't
                    defined for the class '_DesktopCategoryItem'.
[   +3 ms]  - '_DesktopCategoryItem' is from 'package:gallery/pages/home.dart'
            ('lib/pages/home.dart').
[   +2 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'DefaultFocusTraversal'.
[   +1 ms]         child: DefaultFocusTraversal(
[   +1 ms]                ^^^^^^^^^^^^^^^^^^^^^
[   +1 ms] lib/pages/home.dart:414:19: Error: The method
'WidgetOrderFocusTraversalPolicy'
           isn't defined for the class '_DesktopCategoryItem'.
[   +4 ms]  - '_DesktopCategoryItem' is from 'package:gallery/pages/home.dart'
            ('lib/pages/home.dart').
[   +1 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'WidgetOrderFocusTraversalPolicy'.
[   +2 ms]           policy: WidgetOrderFocusTraversalPolicy(),
[   +1 ms]                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[   +1 ms] lib/pages/home.dart:1056:14: Error: The method
'DefaultFocusTraversal' isn't
           defined for the class '_StudyWrapperState'.
[   +3 ms]  - '_StudyWrapperState' is from 'package:gallery/pages/home.dart'
            ('lib/pages/home.dart').
[   +2 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'DefaultFocusTraversal'.
[   +1 ms]       child: DefaultFocusTraversal(
[   +1 ms]              ^^^^^^^^^^^^^^^^^^^^^
[   +2 ms] lib/pages/home.dart:1139:20: Error: Superclass has no method named
'previous'.
[   +1 ms]       return super.previous(_firstFocusNode());
[   +2 ms]                    ^^^^^^^^
[        ] lib/pages/home.dart:1141:20: Error: Superclass has no method named
'previous'.
[   +1 ms]       return super.previous(currentNode);
[        ]                    ^^^^^^^^
[   +2 ms] lib/pages/home.dart:1151:20: Error: Superclass has no method named
'next'.
[   +3 ms]       return super.next(currentNode);
[   +1 ms]                    ^^^^
[+2063 ms] lib/studies/starter/app.dart:53:13: Error: The method
'DefaultFocusTraversal'
                    isn't defined for the class '_StarterAppState'.
[   +3 ms]  - '_StarterAppState' is from
'package:gallery/studies/starter/app.dart'
            ('lib/studies/starter/app.dart').
[   +2 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'DefaultFocusTraversal'.
[   +1 ms]       home: DefaultFocusTraversal(
[   +1 ms]             ^^^^^^^^^^^^^^^^^^^^^
[ +840 ms] lib/studies/crane/backdrop.dart:40:12: Error: The method
'DefaultFocusTraversal'
                    isn't defined for the class '_FrontLayer'.
[   +3 ms]  - '_FrontLayer' is from
'package:gallery/studies/crane/backdrop.dart'
            ('lib/studies/crane/backdrop.dart').
[   +3 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'DefaultFocusTraversal'.
[   +1 ms]     return DefaultFocusTraversal(
[   +1 ms]            ^^^^^^^^^^^^^^^^^^^^^
[   +3 ms] lib/studies/crane/backdrop.dart:147:16: Error: The method
           'DefaultFocusTraversal' isn't defined for the class '_BackdropState'.
[   +3 ms]  - '_BackdropState' is from
'package:gallery/studies/crane/backdrop.dart'
            ('lib/studies/crane/backdrop.dart').
[   +1 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'DefaultFocusTraversal'.
[   +1 ms]         child: DefaultFocusTraversal(
[   +2 ms]                ^^^^^^^^^^^^^^^^^^^^^
[   +1 ms] lib/studies/rally/home.dart:138:12: Error: The method
'DefaultFocusTraversal'
           isn't defined for the class '_HomePageState'.
[   +2 ms]  - '_HomePageState' is from 'package:gallery/studies/rally/home.dart'
            ('lib/studies/rally/home.dart').
[   +1 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'DefaultFocusTraversal'.
[   +1 ms]     return DefaultFocusTraversal(
[        ]            ^^^^^^^^^^^^^^^^^^^^^
[   +1 ms] lib/studies/rally/login.dart:29:12: Error: The method
'DefaultFocusTraversal'
           isn't defined for the class '_LoginPageState'.
[   +2 ms]  - '_LoginPageState' is from
'package:gallery/studies/rally/login.dart'
            ('lib/studies/rally/login.dart').
[   +2 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'DefaultFocusTraversal'.
[        ]     return DefaultFocusTraversal(
[        ]            ^^^^^^^^^^^^^^^^^^^^^
[   +4 ms] lib/layout/focus_traversal_policy.dart:44:20: Error: Superclass has
no method
           named 'previous'.
[   +1 ms]       return super.previous(currentNode);
[   +2 ms]                    ^^^^^^^^
[   +1 ms] lib/layout/focus_traversal_policy.dart:56:20: Error: Superclass has
no method
           named 'next'.
[   +1 ms]       return super.next(currentNode);
[        ]                    ^^^^
[  +54 ms] lib/studies/crane/backlayer.dart:34:12: Error: The method
           'DefaultFocusTraversal' isn't defined for the class
'_BackLayerState'.
[   +2 ms]  - '_BackLayerState' is from
'package:gallery/studies/crane/backlayer.dart'
            ('lib/studies/crane/backlayer.dart').
[   +3 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'DefaultFocusTraversal'.
[   +1 ms]     return DefaultFocusTraversal(
[   +1 ms]            ^^^^^^^^^^^^^^^^^^^^^
[   +1 ms] lib/studies/crane/backlayer.dart:35:15: Error: The method
           'WidgetOrderFocusTraversalPolicy' isn't defined for the class
'_BackLayerState'.
[   +3 ms]  - '_BackLayerState' is from
'package:gallery/studies/crane/backlayer.dart'
            ('lib/studies/crane/backlayer.dart').
[   +2 ms] Try correcting the name to the name of an existing method, or
defining a method
           named 'WidgetOrderFocusTraversalPolicy'.
[   +1 ms]       policy: WidgetOrderFocusTraversalPolicy(),
[        ]               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[+12078 ms]   Compiler message:
[  +32 ms] lib/pages/home.dart(1121,48): error G7D2AEF3C: Type
'WidgetOrderFocusTraversalPolicy' not found.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +2 ms]   class StudyWrapperFocusTraversalPolicy extends
WidgetOrderFocusTraversalPolicy {
[   +3 ms]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[   +1 ms] lib/layout/focus_traversal_policy.dart(13,48): error G7D2AEF3C: Type
'WidgetOrderFocusTraversalPolicy' not found.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]   class EdgeChildrenFocusTraversalPolicy extends
WidgetOrderFocusTraversalPolicy {
[   +1 ms]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[   +2 ms] lib/pages/backdrop.dart(216,14): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_BackdropState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +2 ms]    - '_BackdropState' is from 'package:gallery/pages/backdrop.dart'
('lib/pages/backdrop.dart').
[   +1 ms]   Try correcting the name to the name of an existing method, or
defining a method named 'DefaultFocusTraversal'.
[   +1 ms]         child: DefaultFocusTraversal(
[        ]                ^^^^^^^^^^^^^^^^^^^^^
[        ] lib/pages/backdrop.dart(217,17): error G76A9B1F6: The method
'WidgetOrderFocusTraversalPolicy' isn't defined for the class '_BackdropState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +6 ms]    - '_BackdropState' is from 'package:gallery/pages/backdrop.dart'
('lib/pages/backdrop.dart').
[   +1 ms]   Try correcting the name to the name of an existing method, or
defining a method named 'WidgetOrderFocusTraversalPolicy'.
[   +1 ms]           policy: WidgetOrderFocusTraversalPolicy(),
[        ]                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[        ] lib/pages/backdrop.dart(230,12): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_BackdropState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]    - '_BackdropState' is from 'package:gallery/pages/backdrop.dart'
('lib/pages/backdrop.dart').
[   +4 ms]   Try correcting the name to the name of an existing method, or
defining a method named 'DefaultFocusTraversal'.
[        ]       return DefaultFocusTraversal(
[        ]              ^^^^^^^^^^^^^^^^^^^^^
[        ] lib/pages/home.dart(413,16): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_DesktopCategoryItem'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]    - '_DesktopCategoryItem' is from 'package:gallery/pages/home.dart'
('lib/pages/home.dart').
[   +1 ms]   Try correcting the name to the name of an existing method, or
defining a method named 'DefaultFocusTraversal'.
[   +1 ms]           child: DefaultFocusTraversal(
[   +2 ms]                  ^^^^^^^^^^^^^^^^^^^^^
[   +2 ms] lib/pages/home.dart(414,19): error G76A9B1F6: The method
'WidgetOrderFocusTraversalPolicy' isn't defined for the class
'_DesktopCategoryItem'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]    - '_DesktopCategoryItem' is from 'package:gallery/pages/home.dart'
('lib/pages/home.dart').
[   +1 ms]   Try correcting the name to the name of an existing method, or
defining a method named 'WidgetOrderFocusTraversalPolicy'.
[   +1 ms]             policy: WidgetOrderFocusTraversalPolicy(),
[        ]                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[   +1 ms] lib/pages/home.dart(1056,14): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_StudyWrapperState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]    - '_StudyWrapperState' is from 'package:gallery/pages/home.dart'
('lib/pages/home.dart').
[   +2 ms]   Try correcting the name to the name of an existing method, or
defining a method named 'DefaultFocusTraversal'.
[        ]         child: DefaultFocusTraversal(
[        ]                ^^^^^^^^^^^^^^^^^^^^^
[        ] lib/pages/home.dart(1139,20): error GCBCEA54B: Superclass has no
method named 'previous'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]         return super.previous(_firstFocusNode());
[        ]                      ^^^^^^^^
[        ] lib/pages/home.dart(1141,20): error GCBCEA54B: Superclass has no
method named 'previous'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]         return super.previous(currentNode);
[   +1 ms]                      ^^^^^^^^
[   +1 ms] lib/pages/home.dart(1151,20): error GCBCEA54B: Superclass has no
method named 'next'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]         return super.next(currentNode);
[        ]                      ^^^^
[        ] lib/studies/starter/app.dart(53,13): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_StarterAppState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]    - '_StarterAppState' is from
'package:gallery/studies/starter/app.dart' ('lib/studies/starter/app.dart').
[        ]   Try correcting the name to the name of an existing method, or
defining a method named 'DefaultFocusTraversal'.
[        ]         home: DefaultFocusTraversal(
[        ]               ^^^^^^^^^^^^^^^^^^^^^
[        ] lib/studies/crane/backdrop.dart(40,12): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_FrontLayer'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]    - '_FrontLayer' is from
'package:gallery/studies/crane/backdrop.dart'
('lib/studies/crane/backdrop.dart').
[        ]   Try correcting the name to the name of an existing method, or
defining a method named 'DefaultFocusTraversal'.
[   +2 ms]       return DefaultFocusTraversal(
[        ]              ^^^^^^^^^^^^^^^^^^^^^
[        ] lib/studies/crane/backdrop.dart(147,16): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_BackdropState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]    - '_BackdropState' is from
'package:gallery/studies/crane/backdrop.dart'
('lib/studies/crane/backdrop.dart').
[        ]   Try correcting the name to the name of an existing method, or
defining a method named 'DefaultFocusTraversal'.
[        ]           child: DefaultFocusTraversal(
[        ]                  ^^^^^^^^^^^^^^^^^^^^^
[        ] lib/studies/rally/home.dart(138,12): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_HomePageState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]    - '_HomePageState' is from
'package:gallery/studies/rally/home.dart' ('lib/studies/rally/home.dart').
[        ]   Try correcting the name to the name of an existing method, or
defining a method named 'DefaultFocusTraversal'.
[        ]       return DefaultFocusTraversal(
[        ]              ^^^^^^^^^^^^^^^^^^^^^
[   +2 ms] lib/studies/rally/login.dart(29,12): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_LoginPageState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]    - '_LoginPageState' is from
'package:gallery/studies/rally/login.dart' ('lib/studies/rally/login.dart').
[        ]   Try correcting the name to the name of an existing method, or
defining a method named 'DefaultFocusTraversal'.
[        ]       return DefaultFocusTraversal(
[        ]              ^^^^^^^^^^^^^^^^^^^^^
[        ] lib/layout/focus_traversal_policy.dart(44,20): error GCBCEA54B:
Superclass has no method named 'previous'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]         return super.previous(currentNode);
[        ]                      ^^^^^^^^
[        ] lib/layout/focus_traversal_policy.dart(56,20): error GCBCEA54B:
Superclass has no method named 'next'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]         return super.next(currentNode);
[   +2 ms]                      ^^^^
[        ] lib/studies/crane/backlayer.dart(34,12): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_BackLayerState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]    - '_BackLayerState' is from
'package:gallery/studies/crane/backlayer.dart'
('lib/studies/crane/backlayer.dart').
[        ]   Try correcting the name to the name of an existing method, or
defining a method named 'DefaultFocusTraversal'.
[        ]       return DefaultFocusTraversal(
[        ]              ^^^^^^^^^^^^^^^^^^^^^
[        ] lib/studies/crane/backlayer.dart(35,15): error G76A9B1F6: The method
'WidgetOrderFocusTraversalPolicy' isn't defined for the class '_BackLayerState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]    - '_BackLayerState' is from
'package:gallery/studies/crane/backlayer.dart'
('lib/studies/crane/backlayer.dart').
[        ]   Try correcting the name to the name of an existing method, or
defining a method named 'WidgetOrderFocusTraversalPolicy'.
[        ]         policy: WidgetOrderFocusTraversalPolicy(),
[        ]                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[        ]   Target kernel_snapshot failed: Exception: Errors during snapshot
creation: null
[   +3 ms]   Failed to build bundle.
[        ] C:\Program Files (x86)\Microsoft Visual
Studio\2019\Community\MSBuild\Microsoft\VC\v160\Microsoft.CppCommon.targets(272,
5): error MSB3073: The command
""D:\code\flutter\samples\gallery\windows\scripts\prepare_dependencies" Debug
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ] C:\Program Files (x86)\Microsoft Visual
Studio\2019\Community\MSBuild\Microsoft\VC\v160\Microsoft.CppCommon.targets(272,
5): error MSB3073: :VCEnd" exited with code 1.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ] Done Building Project
"D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj" (default targets)
-- FAILED.
[        ] Done Building Project
"D:\code\flutter\samples\gallery\windows\Runner.vcxproj.metaproj" (default
targets) -- FAILED.
[        ] Done Building Project
"D:\code\flutter\samples\gallery\windows\Runner.sln" (default targets) --
FAILED.
[        ] Build FAILED.
[        ] "D:\code\flutter\samples\gallery\windows\Runner.sln" (default target)
(1) ->
[   +1 ms] "D:\code\flutter\samples\gallery\windows\Runner.vcxproj.metaproj"
(default target) (2) ->
[        ] "D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj"
(default target) (3) ->
[        ] (CustomBuildStep target) ->
[   +2 ms]   lib/pages/home.dart(1121,48): error G7D2AEF3C: Type
'WidgetOrderFocusTraversalPolicy' not found.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]   lib/layout/focus_traversal_policy.dart(13,48): error G7D2AEF3C:
Type 'WidgetOrderFocusTraversalPolicy' not found.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]   lib/pages/backdrop.dart(216,14): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_BackdropState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]   lib/pages/backdrop.dart(217,17): error G76A9B1F6: The method
'WidgetOrderFocusTraversalPolicy' isn't defined for the class '_BackdropState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]   lib/pages/backdrop.dart(230,12): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_BackdropState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]   lib/pages/home.dart(413,16): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_DesktopCategoryItem'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]   lib/pages/home.dart(414,19): error G76A9B1F6: The method
'WidgetOrderFocusTraversalPolicy' isn't defined for the class
'_DesktopCategoryItem'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]   lib/pages/home.dart(1056,14): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_StudyWrapperState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]   lib/pages/home.dart(1139,20): error GCBCEA54B: Superclass has no
method named 'previous'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]   lib/pages/home.dart(1141,20): error GCBCEA54B: Superclass has no
method named 'previous'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]   lib/pages/home.dart(1151,20): error GCBCEA54B: Superclass has no
method named 'next'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +3 ms]   lib/studies/starter/app.dart(53,13): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_StarterAppState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]   lib/studies/crane/backdrop.dart(40,12): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_FrontLayer'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]   lib/studies/crane/backdrop.dart(147,16): error G76A9B1F6: The
method 'DefaultFocusTraversal' isn't defined for the class '_BackdropState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]   lib/studies/rally/home.dart(138,12): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_HomePageState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]   lib/studies/rally/login.dart(29,12): error G76A9B1F6: The method
'DefaultFocusTraversal' isn't defined for the class '_LoginPageState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]   lib/layout/focus_traversal_policy.dart(44,20): error GCBCEA54B:
Superclass has no method named 'previous'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]   lib/layout/focus_traversal_policy.dart(56,20): error GCBCEA54B:
Superclass has no method named 'next'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]   lib/studies/crane/backlayer.dart(34,12): error G76A9B1F6: The
method 'DefaultFocusTraversal' isn't defined for the class '_BackLayerState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +3 ms]   lib/studies/crane/backlayer.dart(35,15): error G76A9B1F6: The
method 'WidgetOrderFocusTraversalPolicy' isn't defined for the class
'_BackLayerState'.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms]   C:\Program Files (x86)\Microsoft Visual
Studio\2019\Community\MSBuild\Microsoft\VC\v160\Microsoft.CppCommon.targets(272,
5): error MSB3073: The command
""D:\code\flutter\samples\gallery\windows\scripts\prepare_dependencies" Debug
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[   +1 ms] C:\Program Files (x86)\Microsoft Visual
Studio\2019\Community\MSBuild\Microsoft\VC\v160\Microsoft.CppCommon.targets(272,
5): error MSB3073: :VCEnd" exited with code 1.
[D:\code\flutter\samples\gallery\windows\FlutterBuild.vcxproj]
[        ]     0 Warning(s)
[        ]     21 Error(s)
[        ] Time Elapsed 00:00:17.76
[  +12 ms] Building Windows application... (completed in 20.1s)
[   +2 ms] Exception: Build process failed. To view the stack trace, please run
`flutter
           run -d windows -v`.
[   +2 ms] "flutter run" took 21,371ms.

#0      throwToolExit (package:flutter_tools/src/base/common.dart:14:3)
#1      RunCommand.runCommand
(package:flutter_tools/src/commands/run.dart:568:7)
<asynchronous suspension>
#2      FlutterCommand.verifyThenRunCommand
(package:flutter_tools/src/runner/flutter_command.dart:711:18)
<asynchronous suspension>
#3      FlutterCommand.run.<anonymous closure>
(package:flutter_tools/src/runner/flutter_command.dart:609:33)
<asynchronous suspension>
#4      FlutterCommand.run.<anonymous closure>
(package:flutter_tools/src/runner/flutter_command.dart)
#5      AppContext.run.<anonymous closure>
(package:flutter_tools/src/base/context.dart:150:29)
#6      _rootRun (dart:async/zone.dart:1126:13)
#7      _CustomZone.run (dart:async/zone.dart:1023:19)
#8      _runZoned (dart:async/zone.dart:1518:10)
#9      runZoned (dart:async/zone.dart:1465:12)
#10     AppContext.run (package:flutter_tools/src/base/context.dart:149:18)
#11     FlutterCommand.run
(package:flutter_tools/src/runner/flutter_command.dart:599:20)
#12     CommandRunner.runCommand (package:args/command_runner.dart:197:27)
#13     FlutterCommandRunner.runCommand.<anonymous closure>
(package:flutter_tools/src/runner/flutter_command_runner.dart:338:21)
<asynchronous suspension>
#14     FlutterCommandRunner.runCommand.<anonymous closure>
(package:flutter_tools/src/runner/flutter_command_runner.dart)
#15     AppContext.run.<anonymous closure>
(package:flutter_tools/src/base/context.dart:150:29)
#16     _rootRun (dart:async/zone.dart:1126:13)
#17     _CustomZone.run (dart:async/zone.dart:1023:19)
#18     _runZoned (dart:async/zone.dart:1518:10)
#19     runZoned (dart:async/zone.dart:1465:12)
#20     AppContext.run (package:flutter_tools/src/base/context.dart:149:18)
#21     FlutterCommandRunner.runCommand
(package:flutter_tools/src/runner/flutter_command_runner.dart:288:19)
#22     CommandRunner.run.<anonymous closure>
(package:args/command_runner.dart:112:25)
#23     new Future.sync (dart:async/future.dart:224:31)
#24     CommandRunner.run (package:args/command_runner.dart:112:14)
#25     FlutterCommandRunner.run
(package:flutter_tools/src/runner/flutter_command_runner.dart:231:18)
#26     run.<anonymous closure>.<anonymous closure>
(package:flutter_tools/runner.dart:63:22)
#27     _rootRun (dart:async/zone.dart:1126:13)
#28     _CustomZone.run (dart:async/zone.dart:1023:19)
#29     _runZoned (dart:async/zone.dart:1518:10)
#30     runZoned (dart:async/zone.dart:1502:12)
#31     run.<anonymous closure> (package:flutter_tools/runner.dart:61:18)
<asynchronous suspension>
#32     run.<anonymous closure> (package:flutter_tools/runner.dart)
#33     runInContext.runnerWrapper
(package:flutter_tools/src/context_runner.dart:69:18)
<asynchronous suspension>
#34     runInContext.runnerWrapper
(package:flutter_tools/src/context_runner.dart)
#35     AppContext.run.<anonymous closure>
(package:flutter_tools/src/base/context.dart:150:29)
#36     _rootRun (dart:async/zone.dart:1126:13)
#37     _CustomZone.run (dart:async/zone.dart:1023:19)
#38     _runZoned (dart:async/zone.dart:1518:10)
#39     runZoned (dart:async/zone.dart:1465:12)
#40     AppContext.run (package:flutter_tools/src/base/context.dart:149:18)
#41     runInContext (package:flutter_tools/src/context_runner.dart:72:24)
#42     run (package:flutter_tools/runner.dart:50:10)
<asynchronous suspension>
#43     main (package:flutter_tools/executable.dart:69:9)
#44     main
(file:///D:/apps/flutter/packages/flutter_tools/bin/flutter_tools.dart:8:3)
#45     _startIsolate.<anonymous closure>
(dart:isolate-patch/isolate_patch.dart:299:32)
#46     _RawReceivePortImpl._handleMessage
(dart:isolate-patch/isolate_patch.dart:168:12)




D:\code\flutter\samples\gallery>

[visual sample index] Clarify contribution guidelines

[Veggie Season] Unclear what the main feed's sorting is

Target of URI doesn't exist: 'package:gallery/l10n/gallery_localizations.dart

I don't exist the package

Remove repo-wide gitignore file

Now that we have so many individual projects, some of which are traditional Android and iOS apps, we need to remove the repo's overall .gitignore and standardize the project-level ignore files.

[gallery] flutter pub run grinder l10n got problem

-> flutter pub run grinder l10n

Output;

grinder running generate-localizations l10n

generate-localizations
  /home/aliyazdi75/flutter/bin/cache/dart-sdk/bin/dart /home/aliyazdi75/flutter/dev/tools/localization/bin/gen_l10n.dart --template-arb-file=intl_en_US.arb --output-localization-file=gallery_localizations.dart --output-class=GalleryLocalizations --preferred-supported-locales=["en_US"]
  Error: Could not resolve the package 'args' in 'package:args/args.dart'.
  Error: Could not resolve the package 'file' in 'package:file/local.dart'.
  Error: Could not resolve the package 'path' in 'package:path/path.dart'.
  ../../../../flutter/dev/tools/localization/bin/gen_l10n.dart:8:8: Error: Not found: 'package:args/args.dart'
  import 'package:args/args.dart' as argslib;
         ^
  ../../../../flutter/dev/tools/localization/bin/gen_l10n.dart:9:8: Error: Not found: 'package:file/local.dart'
  import 'package:file/local.dart' as local;
         ^
  ../../../../flutter/dev/tools/localization/bin/gen_l10n.dart:10:8: Error: Not found: 'package:path/path.dart'
  import 'package:path/path.dart' as path;
         ^
  Error: Could not resolve the package 'file' in 'package:file/file.dart'.
  Error: Could not resolve the package 'meta' in 'package:meta/meta.dart'.
  ../../../../flutter/dev/tools/localization/gen_l10n.dart:10:8: Error: Not found: 'package:path/path.dart'
  import 'package:path/path.dart' as path;
         ^
  ../../../../flutter/dev/tools/localization/localizations_utils.dart:9:8: Error: Not found: 'package:args/args.dart'
  import 'package:args/args.dart' as argslib;
         ^

failed with exit code 254
#0      run (package:grinder/src/run.dart:48:5)
#1      Dart.run (package:grinder/grinder_sdk.dart:75:12)
#2      generateLocalizations (file:///home/aliyazdi75/Documents/FlutterPackages/samples-master/gallery/tool/grind.dart:38:8)
#3      _LibraryMirror._invoke (dart:mirrors-patch/mirrors_impl.dart:1086:36)
#4      _ObjectMirror.invoke (dart:mirrors-patch/mirrors_impl.dart:243:25)
#5      TaskDiscovery.discoverDeclaration.<anon> (package:grinder/src/discover_tasks.dart:79:38)
#6      _rootRun (dart:async/zone.dart:1126:13)
#7      _CustomZone.run (dart:async/zone.dart:1023:19)
#8      _runZoned (dart:async/zone.dart:1518:10)
#9      runZoned (dart:async/zone.dart:1465:12)
#10     ZonedValue.withValue (package:grinder/src/utils.dart:112:12)
#11     GrinderTask.execute (package:grinder/src/grinder_task.dart:63:27)
#12     Grinder._invokeTask (package:grinder/src/grinder.dart:193:27)
#13     Grinder.start.<anon> (package:grinder/src/grinder.dart:168:16)
#14     Future.forEach.<anon> (dart:async/future.dart:492:26)
#15     Future.doWhile.<anon> (dart:async/future.dart:534:26)
#16     _RootZone.runUnaryGuarded (dart:async/zone.dart:1316:10)
#17     _RootZone.bindUnaryCallbackGuarded.<anon> (dart:async/zone.dart:1355:26)
#18     Future.doWhile (dart:async/future.dart:549:18)
#19     Future.forEach (dart:async/future.dart:490:12)
#20     Grinder.start (package:grinder/src/grinder.dart:167:21)
#21     runTasks (package:grinder/src/cli.dart:67:39)
#22     grind (package:grinder/grinder.dart:46:12)
#23     main (file:///home/aliyazdi75/Documents/FlutterPackages/samples-master/gallery/tool/grind.dart:12:33)
pub finished with exit code 1

[Veggieseasons] Let overscroll happen in the header section

Instead of between the header and the list under it. It should also zoom out the image a bit. See the iOS podcast app. One a podcast and drag down.

Update the navigation rail sample once the component officially lands

Once flutter/flutter#49574 lands, https://github.com/flutter/samples/blob/master/experimental/web_dashboard/lib/src/widgets/third_party/adaptive_scaffold.dart should be updated

The place_tracker sample should use a stock state mgmt approach

The place_tracker sample in flutter/samples is using a custom InheritedWidget for state management, rather than an off-the-shelf approach. While it's fine to show folks how to write their own InheritedWidget to hold app state, place_tracker should be focused entirely on Maps.

Veggieseasons sample drops frames while scrolling

I noticed that the veggieseasons sample app drops below 60fps while scrolling through the veggies on the home screen.
I get an average of around 20ms/frame GPU time and max GPU time of around 30 ms/frame.
So it only runs about 50fps, which seems like a small deviation but on a fixed refresh display it leads to micro stuttering.

Test Setup:

Flutter 1.7.4 release build.
I turned on the performance overlay by adding to showPerformanceOverlay: true to the CupertinoApp widget.
I testest both on a Galaxy S8 with Android 9.0
and a iPad 6th generation running iOS 12.3.1
Both had similar frame times.

I know that these are not fastest devices but it is just a simple list after all and I would expect scrolling to be smooth.

[slide_puzzle] error while running slide_puzzle

Description

while running slide puzzle project getting this error :
Compiler message:
lib/src/widgets/decoration_image_plus.dart:10:7: Error: The non-abstract class 'DecorationImagePlus' is missing implementations for these members:
- DecorationImage.onError

plattform_view demo code does not work

When you try to run the test application, it opens and closes immediately.
Attached to this comment the data of my work environment and I would like to point out that I have already tried with the most recent version of Dart and Flutter and it did not work so I decided to make a downgrade.

iMac:platform_view_swift red5g$ flutter doctor -v
[✓] Flutter (Channel unknown, v1.12.13+hotfix.5, on Mac OS X 10.15.2 19C57, locale en-SV)
• Flutter version 1.12.13+hotfix.5 at /Users/red5g/Documents/development/flutter/flutter
• Framework revision 27321ebbad (9 weeks ago), 2019-12-10 18:15:01 -0800
• Engine revision 2994f7e1e6
• Dart version 2.7.0

[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
• Android SDK at /Users/red5g/Library/Android/sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-29, build-tools 29.0.3
• Java binary at: /Users/red5g/.sdkman/candidates/java/current/bin/java
• Java version OpenJDK Runtime Environment (Zulu 8.44.0.9-CA-macosx) (build 1.8.0_242-b20)
• All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.3)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 11.3, Build version 11C29
• CocoaPods version 1.8.4

[✓] Android Studio (version 3.5)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin version 43.0.1
• Dart plugin version 191.8593
• Java version OpenJDK Runtime Environment (build 1.8.0_202-release-1483-b49-5587405)

[!] Android Studio
• Android Studio at /Users/red5g/Library/Android/sdk/Contents
✗ Flutter plugin not installed; this adds Flutter specific functionality.
✗ Dart plugin not installed; this adds Dart specific functionality.
✗ Android Studio not found at /Users/red5g/Library/Android/sdk/Contents
• Try updating or re-installing Android Studio.

[✓] Connected device (1 available)
• iPhone • 8f90f344ac80f6853eadb60e634ef2cb7b39232a • ios • iOS 13.3.1

I will be aware of this problem since my project depends on this.
Thank you

[codelabs] !_debugLocked': is not true. on hot reload

The Problem

Once this error occurs, you have to stop the app before performing any more hot reloads:

Steps to Reproduce

I've been going through the Flutter tutorial at this point (https://codelabs.developers.google.com/codelabs/first-flutter-app-pt2/#5)

Dart file here: Rename to main.dart

1. Run main.dart using either Android emulator or iOS emulator
2. Verify that it's working
3. Uncomment lines 71-82
4. Save file (hot reload)
5. Observe that the code fails. (I don't yet know why this doesn't work, but I digress)
6. Comment lines 71-82
7. Save file

Target Platform: Android and iOS
Target OS version/browser: Android API 29 x86
Devices: Nexus 5X emulator, iPhone 11 Pro Max emulator

Logs

Sorry it's not verbose, but it looks like it's related to hot reload.

Syncing files to device Android SDK built for x86...

════════ Exception caught by widgets library ═══════════════════════════════════════════════════════
The following assertion was thrown building Navigator-[GlobalObjectKey<NavigatorState> _WidgetsAppState#5e8f2](dirty, state: NavigatorState#90e6e(tickers: tracking 2 tickers)):
'package:flutter/src/widgets/navigator.dart': Failed assertion: line 2330 pos 12: '!_debugLocked': is not true.


Either the assertion indicates an error in the framework itself, or we should provide substantially more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
  https://github.com/flutter/flutter/issues/new?template=BUG.md

The relevant error-causing widget was: 
  MaterialApp file:///Users/jeramy/Projects/flutter/car_games/lib/main.dart:10:12
When the exception was thrown, this was the stack: 
flutter/flutter#2      NavigatorState.build (package:flutter/src/widgets/navigator.dart:2330:12)
flutter/flutter#3      StatefulElement.build (package:flutter/src/widgets/framework.dart:4334:27)
flutter/flutter#4      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4223:15)
flutter/flutter#5      Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
flutter/flutter#6      StatefulElement.update (package:flutter/src/widgets/framework.dart:4413:5)
...
════════════════════════════════════════════════════════════════════════════════════════════════════
Reloaded 1 of 531 libraries in 2,062ms.

jeramy@Jeramys-MacBook-Pro car_games $ flutter analyze
Analyzing car_games...                                                  
No issues found! (ran in 4.4s)

[✓] Flutter (Channel stable, v1.12.13+hotfix.5, on Mac OS X 10.14.6 18G87, locale en-CA)
    • Flutter version 1.12.13+hotfix.5 at /Users/jeramy/flutter
    • Framework revision 27321ebbad (9 days ago), 2019-12-10 18:15:01 -0800
    • Engine revision 2994f7e1e6
    • Dart version 2.7.0

 
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at /Users/jeramy/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-29, build-tools 29.0.2
    • ANDROID_HOME = /Users/jeramy/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_202-release-1483-b49-5587405)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.3)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.3, Build version 11C29
    • CocoaPods version 1.8.4

[✓] Android Studio (version 3.5)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 42.1.1
    • Dart plugin version 191.8593
    • Java version OpenJDK Runtime Environment (build 1.8.0_202-release-1483-b49-5587405)

[✓] VS Code (version 1.40.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.7.1

[✓] Connected device (1 available)
    • Android SDK built for x86 • emulator-5554 • android-x86 • Android 9 (API 28) (emulator)

• No issues found!```

Flutter example

Problems with https://flutter.github.io/samples/, unable to copy code

In https://flutter.github.io/samples/ I can see such errors in the developer console

And I have

natives.dart:14 Overflow on channel: flutter/platform.  Messages on this channel are being discarded in FIFO fashion.  The engine may not be running or you need to adjust the buffer size if of the channel.

every time when trying to copy the code via copy button. So the copy button is not working

samples/gallery does not work with master

I'm not sure if samples is supposed to work with master or not. :)

But it makes it difficult to test to see the latest performance improvements in flutter web for example:

[✓] Flutter (Channel master, v1.15.4-pre.134, on Mac OS X 10.15.2 19C57, locale en-US)
    • Flutter version 1.15.4-pre.134 at /Users/eseidel/Projects/flutter/flutter
    • Framework revision bf8e2c1449 (17 hours ago), 2020-02-21 14:21:25 -0800
    • Engine revision f2f8c342be
    • Dart version 2.8.0 (build 2.8.0-dev.9.0 0f141be8bd)

Compiler message:
lib/pages/home.dart:1121:48: Error: Type 'WidgetOrderFocusTraversalPolicy' not found.                              
class StudyWrapperFocusTraversalPolicy extends WidgetOrderFocusTraversalPolicy {                                   
                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                                     
lib/layout/focus_traversal_policy.dart:13:48: Error: Type 'WidgetOrderFocusTraversalPolicy' not found.             
class EdgeChildrenFocusTraversalPolicy extends WidgetOrderFocusTraversalPolicy {                                   
                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                                     
lib/pages/backdrop.dart:217:17: Error: The method 'WidgetOrderFocusTraversalPolicy' isn't defined for the class '_BackdropState'.
 - '_BackdropState' is from 'package:gallery/pages/backdrop.dart' ('lib/pages/backdrop.dart').                     
Try correcting the name to the name of an existing method, or defining a method named 'WidgetOrderFocusTraversalPolicy'.
        policy: WidgetOrderFocusTraversalPolicy(),                                                                 
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                                                                    
lib/pages/home.dart:414:19: Error: The method 'WidgetOrderFocusTraversalPolicy' isn't defined for the class '_DesktopCategoryItem'.
 - '_DesktopCategoryItem' is from 'package:gallery/pages/home.dart' ('lib/pages/home.dart').                       
Try correcting the name to the name of an existing method, or defining a method named 'WidgetOrderFocusTraversalPolicy'.
          policy: WidgetOrderFocusTraversalPolicy(),                                                               
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                                                                  
lib/pages/home.dart:1057:17: Error: The argument type 'StudyWrapperFocusTraversalPolicy' can't be assigned to the parameter type
'FocusTraversalPolicy'.
 - 'StudyWrapperFocusTraversalPolicy' is from 'package:gallery/pages/home.dart' ('lib/pages/home.dart').           
 - 'FocusTraversalPolicy' is from 'package:flutter/src/widgets/focus_traversal.dart'                               
 ('../../flutter/packages/flutter/lib/src/widgets/focus_traversal.dart').
        policy: StudyWrapperFocusTraversalPolicy(                                                                  
                ^                                                                                                  
lib/pages/home.dart:1139:20: Error: Superclass has no method named 'previous'.                                     
      return super.previous(_firstFocusNode());                                                                    
                   ^^^^^^^^                                                                                        
lib/pages/home.dart:1141:20: Error: Superclass has no method named 'previous'.                                     
      return super.previous(currentNode);                                                                          
                   ^^^^^^^^                                                                                        
lib/pages/home.dart:1151:20: Error: Superclass has no method named 'next'.                                         
      return super.next(currentNode);                                                                              
                   ^^^^                                                                                            
lib/studies/starter/app.dart:54:17: Error: The argument type 'EdgeChildrenFocusTraversalPolicy' can't be assigned to the parameter type
'FocusTraversalPolicy'.
 - 'EdgeChildrenFocusTraversalPolicy' is from 'package:gallery/layout/focus_traversal_policy.dart'                 
 ('lib/layout/focus_traversal_policy.dart').
 - 'FocusTraversalPolicy' is from 'package:flutter/src/widgets/focus_traversal.dart'                               
 ('../../flutter/packages/flutter/lib/src/widgets/focus_traversal.dart').
        policy: EdgeChildrenFocusTraversalPolicy(                                                                  
                ^                                                                                                  
lib/studies/rally/home.dart:139:15: Error: The argument type 'EdgeChildrenFocusTraversalPolicy' can't be assigned to the parameter type
'FocusTraversalPolicy'.
 - 'EdgeChildrenFocusTraversalPolicy' is from 'package:gallery/layout/focus_traversal_policy.dart'                 
 ('lib/layout/focus_traversal_policy.dart').
 - 'FocusTraversalPolicy' is from 'package:flutter/src/widgets/focus_traversal.dart'                               
 ('../../flutter/packages/flutter/lib/src/widgets/focus_traversal.dart').
      policy: EdgeChildrenFocusTraversalPolicy(                                                                    
              ^                                                                                                    
lib/studies/rally/login.dart:30:15: Error: The argument type 'EdgeChildrenFocusTraversalPolicy' can't be assigned to the parameter type
'FocusTraversalPolicy'.
 - 'EdgeChildrenFocusTraversalPolicy' is from 'package:gallery/layout/focus_traversal_policy.dart'                 
 ('lib/layout/focus_traversal_policy.dart').
 - 'FocusTraversalPolicy' is from 'package:flutter/src/widgets/focus_traversal.dart'                               
 ('../../flutter/packages/flutter/lib/src/widgets/focus_traversal.dart').
      policy: EdgeChildrenFocusTraversalPolicy(                                                                    
              ^                                                                                                    
lib/layout/focus_traversal_policy.dart:44:20: Error: Superclass has no method named 'previous'.                    
      return super.previous(currentNode);                                                                          
                   ^^^^^^^^                                                                                        
lib/layout/focus_traversal_policy.dart:56:20: Error: Superclass has no method named 'next'.                        
      return super.next(currentNode);                                                                              
                   ^^^^                                                                                            
lib/studies/crane/backlayer.dart:35:15: Error: The method 'WidgetOrderFocusTraversalPolicy' isn't defined for the class '_BackLayerState'.
 - '_BackLayerState' is from 'package:gallery/studies/crane/backlayer.dart' ('lib/studies/crane/backlayer.dart').  
Try correcting the name to the name of an existing method, or defining a method named 'WidgetOrderFocusTraversalPolicy'.
      policy: WidgetOrderFocusTraversalPolicy(),  

FYI @gspencergoog (who I suspect worked on the focus changes) and @ferhatb who mentioned this to me.

Error: Could not find the correct Provider<CartModel> above this _CartList Widget

I'm getting an error in this line

samples/provider_shopper/lib/screens/cart.dart

Line 40 in 5a5cc8a

var cart = Provider.of<CartModel>(context);

════════ Exception caught by widgets library ═══════════════════════════════════

Error: Could not find the correct Provider<CartModel> above this _CartList Widget

To fix, please:

  * Ensure the Provider<CartModel> is an ancestor to this _CartList Widget
  * Provide types to Provider<CartModel>
  * Provide types to Consumer<CartModel>
  * Provide types to Provider.of<CartModel>()
  * Ensure the correct `context` is being used.

The relevant error-causing widget was
    _CartList 
lib/screens/cart.dart:22
When the exception was thrown, this was the stack
#0      Provider.of 
package:provider/src/provider.dart:226
#1      _CartList.build 
lib/screens/cart.dart:38
#2      StatelessElement.build 
package:flutter/…/widgets/framework.dart:4291
#3      ComponentElement.performRebuild 
package:flutter/…/widgets/framework.dart:4223
#4      Element.rebuild 
package:flutter/…/widgets/framework.dart:3947
...

I'm using the same code and dependencies and the cart page doesn't work.

[✓] Flutter (Channel stable, v1.12.13+hotfix.9, on Linux, locale en_US.UTF-8)
    • Flutter version 1.12.13+hotfix.9 at /opt/flutter
    • Framework revision f139b11009 (12 days ago), 2020-03-30 13:57:30 -0700
    • Engine revision af51afceb8
    • Dart version 2.7.2

 
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
    • Android SDK at /home/eliu/Android/Sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-29, build-tools 29.0.3
    • Java binary at: /opt/android-studio/jre/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b4-5784211)
    • All Android licenses accepted.

[✓] Android Studio (version 3.6)
    • Android Studio at /opt/android-studio
    • Flutter plugin version 45.0.1
    • Dart plugin version 192.7761
    • Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b4-5784211)

[✓] VS Code (version 1.44.0)
    • VS Code at /usr/share/code
    • Flutter extension version 3.9.1

[✓] Connected device (1 available)
    • AOSP on IA Emulator • emulator-5554 • android-x86 • Android 9 (API 28) (emulator)

• No issues found!

Add flutter_gallery__transition_perf of the new Flutter gallery app

It's important to ensure that our new Flutter gallery app (already released in Google play store) is performant. Therefore, the new app should at least have some automated perf test like the old flutter_gallery__transition_perf test to continuously monitor its performance.

[platform_design] Some of the UI elements turn invisible in dark mode

I found the following issues in the platform_design app:

• The Settings show black on black text in dark mode.
• There are a couple of more widgets that don't go well with the dark mode throughout the app.

Screenshots:

I'm currently working on the solution.

I've read the contribution guide but this is my first PR in a big repo. So, please bear with me.
I'm thinking of just changing color to grab from the theme wherever it is hardcoded.

Let me know what you think of it @RedBrogdon @johnpryan @domesticmouse

errors compiling gallery with master channel for desktop

I followed the instructions in https://flutter.dev/desktop for desktop support and a number of samples compile and run.

When I try to compile the gallery I get the errors below.

If I cd into the animations folder and do the same, the animations sample compiles and runs fine.

Compiler message:
lib/pages/home.dart:1121:48: Error: Type 'WidgetOrderFocusTraversalPolicy' not found.
class StudyWrapperFocusTraversalPolicy extends WidgetOrderFocusTraversalPolicy {
                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
lib/layout/focus_traversal_policy.dart:13:48: Error: Type 'WidgetOrderFocusTraversalPolicy' not found.
class EdgeChildrenFocusTraversalPolicy extends WidgetOrderFocusTraversalPolicy {
                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Running pod install...                                              2.9s
lib/pages/backdrop.dart:216:14: Error: The method 'DefaultFocusTraversal' isn't defined for the class '_BackdropState'.
 - '_BackdropState' is from 'package:gallery/pages/backdrop.dart' ('lib/pages/backdrop.dart').
Try correcting the name to the name of an existing method, or defining a method named 'DefaultFocusTraversal'.
      child: DefaultFocusTraversal(
             ^^^^^^^^^^^^^^^^^^^^^
lib/pages/backdrop.dart:217:17: Error: The method 'WidgetOrderFocusTraversalPolicy' isn't defined for the class '_BackdropState'.
 - '_BackdropState' is from 'package:gallery/pages/backdrop.dart' ('lib/pages/backdrop.dart').
Try correcting the name to the name of an existing method, or defining a method named 'WidgetOrderFocusTraversalPolicy'.
        policy: WidgetOrderFocusTraversalPolicy(),
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
lib/pages/backdrop.dart:230:12: Error: The method 'DefaultFocusTraversal' isn't defined for the class '_BackdropState'.
 - '_BackdropState' is from 'package:gallery/pages/backdrop.dart' ('lib/pages/backdrop.dart').
Try correcting the name to the name of an existing method, or defining a method named 'DefaultFocusTraversal'.
    return DefaultFocusTraversal(
           ^^^^^^^^^^^^^^^^^^^^^
2020-02-29 19:57:45.617 xcodebuild[70155:2591448]  iOSSimulator: [SimServiceContext sharedServiceContextForDeveloperDir:error:] returned nil (Error Domain=DVTCoreSimulatorAdditionsErrorDomain Code=3 "CoreSimulator is out of date. Current version (581.2.0) is older than build version (681.5.1)." UserInfo={NSLocalizedDescription=CoreSimulator is out of date. Current version (581.2.0) is older than build version (681.5.1).}). Simulator device support disabled.
lib/pages/home.dart:413:16: Error: The method 'DefaultFocusTraversal' isn't defined for the class '_DesktopCategoryItem'.
 - '_DesktopCategoryItem' is from 'package:gallery/pages/home.dart' ('lib/pages/home.dart').
Try correcting the name to the name of an existing method, or defining a method named 'DefaultFocusTraversal'.
        child: DefaultFocusTraversal(
               ^^^^^^^^^^^^^^^^^^^^^
lib/pages/home.dart:414:19: Error: The method 'WidgetOrderFocusTraversalPolicy' isn't defined for the class '_DesktopCategoryItem'.
 - '_DesktopCategoryItem' is from 'package:gallery/pages/home.dart' ('lib/pages/home.dart').
Try correcting the name to the name of an existing method, or defining a method named 'WidgetOrderFocusTraversalPolicy'.
          policy: WidgetOrderFocusTraversalPolicy(),
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
lib/pages/home.dart:1056:14: Error: The method 'DefaultFocusTraversal' isn't defined for the class '_StudyWrapperState'.
 - '_StudyWrapperState' is from 'package:gallery/pages/home.dart' ('lib/pages/home.dart').
Try correcting the name to the name of an existing method, or defining a method named 'DefaultFocusTraversal'.
      child: DefaultFocusTraversal(
             ^^^^^^^^^^^^^^^^^^^^^
lib/pages/home.dart:1139:20: Error: Superclass has no method named 'previous'.
      return super.previous(_firstFocusNode());
                   ^^^^^^^^
lib/pages/home.dart:1141:20: Error: Superclass has no method named 'previous'.
      return super.previous(currentNode);
                   ^^^^^^^^
lib/pages/home.dart:1151:20: Error: Superclass has no method named 'next'.
      return super.next(currentNode);
                   ^^^^
lib/studies/starter/app.dart:53:13: Error: The method 'DefaultFocusTraversal' isn't defined for the class '_StarterAppState'.
 - '_StarterAppState' is from 'package:gallery/studies/starter/app.dart' ('lib/studies/starter/app.dart').
Try correcting the name to the name of an existing method, or defining a method named 'DefaultFocusTraversal'.
      home: DefaultFocusTraversal(
            ^^^^^^^^^^^^^^^^^^^^^
lib/studies/crane/backdrop.dart:40:12: Error: The method 'DefaultFocusTraversal' isn't defined for the class '_FrontLayer'.
 - '_FrontLayer' is from 'package:gallery/studies/crane/backdrop.dart' ('lib/studies/crane/backdrop.dart').
Try correcting the name to the name of an existing method, or defining a method named 'DefaultFocusTraversal'.
    return DefaultFocusTraversal(
           ^^^^^^^^^^^^^^^^^^^^^
lib/studies/crane/backdrop.dart:147:16: Error: The method 'DefaultFocusTraversal' isn't defined for the class '_BackdropState'.
 - '_BackdropState' is from 'package:gallery/studies/crane/backdrop.dart' ('lib/studies/crane/backdrop.dart').
Try correcting the name to the name of an existing method, or defining a method named 'DefaultFocusTraversal'.
        child: DefaultFocusTraversal(
               ^^^^^^^^^^^^^^^^^^^^^
lib/studies/rally/home.dart:138:12: Error: The method 'DefaultFocusTraversal' isn't defined for the class '_HomePageState'.
 - '_HomePageState' is from 'package:gallery/studies/rally/home.dart' ('lib/studies/rally/home.dart').
Try correcting the name to the name of an existing method, or defining a method named 'DefaultFocusTraversal'.
    return DefaultFocusTraversal(
           ^^^^^^^^^^^^^^^^^^^^^
lib/studies/rally/login.dart:29:12: Error: The method 'DefaultFocusTraversal' isn't defined for the class '_LoginPageState'.
 - '_LoginPageState' is from 'package:gallery/studies/rally/login.dart' ('lib/studies/rally/login.dart').
Try correcting the name to the name of an existing method, or defining a method named 'DefaultFocusTraversal'.
    return DefaultFocusTraversal(
           ^^^^^^^^^^^^^^^^^^^^^
lib/layout/focus_traversal_policy.dart:44:20: Error: Superclass has no method named 'previous'.
      return super.previous(currentNode);
                   ^^^^^^^^
lib/layout/focus_traversal_policy.dart:56:20: Error: Superclass has no method named 'next'.
      return super.next(currentNode);
                   ^^^^
lib/studies/crane/backlayer.dart:34:12: Error: The method 'DefaultFocusTraversal' isn't defined for the class '_BackLayerState'.
 - '_BackLayerState' is from 'package:gallery/studies/crane/backlayer.dart' ('lib/studies/crane/backlayer.dart').
Try correcting the name to the name of an existing method, or defining a method named 'DefaultFocusTraversal'.
    return DefaultFocusTraversal(
           ^^^^^^^^^^^^^^^^^^^^^
lib/studies/crane/backlayer.dart:35:15: Error: The method 'WidgetOrderFocusTraversalPolicy' isn't defined for the class '_BackLayerState'.
 - '_BackLayerState' is from 'package:gallery/studies/crane/backlayer.dart' ('lib/studies/crane/backlayer.dart').
Try correcting the name to the name of an existing method, or defining a method named 'WidgetOrderFocusTraversalPolicy'.
      policy: WidgetOrderFocusTraversalPolicy(),
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
** BUILD FAILED **


The following build commands failed:
        Ld /Users/andrew/workspace/samples/gallery/build/macos/Build/Products/Debug/Flutter\ Gallery.app/Contents/MacOS/Flutter\ Gallery normal x86_64
(1 failure)
Building macOS application...
Exception: Build process failed

[visual sample index] Improve cookbook screenshots

Cookbook screenshots should include a screenshot of the running app, most likely the DartPad iframe on the page.

Cookbook scraper instructions

Cookbook scraper source code

Apps in flutter/samples should use the new application template

flutter/flutter#22565 landed a new default flutter template. This allows us to not have to check-in android and ios directories when they have just default content. We should update the app samples in https://github.com/flutter/samples to use it.

add-to-app create an explicit example of launching a flutter screen with prepopulated data

This is pretty much what you have already, but right before presenting a flutter view, invoke a channel message to send something.

bug: dialog message and action buttons unsuitable for logout

Adaptive Music App screenshot: (in platform_design)

One solution could be to have a landing page (login-like page) for new users so that we can use that page on logging out as well. Currently, we directly land on the homepage having the list of songs.
We also need to update the logout dialog message and buttons - "Go back" and "cancel" pretty much makes the same meaning to me.
OR
We could remove the Log out button itself from the profile screen as it is pretty much unfunctional otherwise.

[provider_shopper] Add Widget Tests

In the provider_shopper sample app, we have a widget test already there for demonstration here - https://github.com/flutter/samples/blob/master/provider_shopper/test/widget_test.dart.
I suggest including a driver test for the app as well for demonstration of integration tests. The driver test itself should be pretty straight forward according to the app functioning.

Keyboard blocks text input field in Material > Textfields

If you open the Gallery app and navigate to Material > Textfields and tap to enter text in the password field, the keyboard comes up and covers the input. You can't scroll the view far enough to uncover it.

[visual sample index] Fix Timeflow source code broken link

Source code link for Timeflow sample is broken
It should point to Timeflow repo

[visual sample index] Add analytics

Push a bitcode enabled app to test flight

Now that Bitcode is available for Flutter apps, we'd like to measure what the store actually produces for an IPA.

@RedBrogdon - could we create a build of Veggie Sessions or similar with bitcode enabled, publish it ot test flight, and measure it on some device(s)? I'd be happy to sit with you on this if it helps.

[Veggieseasons] Let the search page feed slide behind the search/tab bar

provider_shopper sample is missing login page

The flutter docs at https://flutter.dev/docs/development/data-and-backend/state-mgmt/simple describe a shopper app that has a login page. However, the sample linked (https://github.com/flutter/samples/tree/master/provider_shopper) does not have that. One of the docs or the sample should be updated to fix this.

Rover' Guide

From quite some time, I had been working on a Project named as Rover's Guide (One Stop Solution for Travellers). In this project, I had used different types of widgets like Circle Avatar, Expanded Widgets etc.
It is a full-fledge project deployed on the web using Flutter Web and GitHub Actions. As I am also looking to contribute to GSoC 2020 on Platform Channel Sample App( Proposal Submitted). So this issue/pr could be a good start for me for contributions towards Sample Repo

Repo, can be found on ths link.
Thanks, looking forwards to a wonderful summer in this pandemic.

[visual samples index] Inaccurate search results when using filters and search

e.g. https://flutter.github.io/samples/#?search=ios&type=cookbook

Daily Notification

MaikuB/flutter_local_notifications#545 (comment)

Referinf to this link. i have same issue, showdaily does not work. i do not know why. Can you send me sample code of your manifest code or something useful that i can edit my code?
Thanks

[visual sample index] Improve PageSpeed Insights score on mobile

The PageSpeed Insights tool scores flutter.github.io/samples at 95 on Desktop, but 72 on mobile. We should take a closer look at the results and improve experience on a mobile phone.

[animations] Improve unit/widget tests in the app.

Description

Currently, in the widget test, we are only checking whether the Text is rendered correctly or not. Adding more widget/unit tests in the application can help Flutter enthusiastic to get more detailed examples of the writing unit/widget test.

The app uses many different widgets which can demonstrate proper techniques to write widget test. For example, we can demonstrate the proper technique to write widget test for ListView.

I would like to work on this issue.

[animations] Add Animation Sample

Hey @RedBrogdon @johnpryan ,
I would like to add a simple Slide Transition widget demo to the basics/ of animations which is missing from it.
Should I go ahead and begin working on it?

BUG | Crane example has wrong top margin on Desktop.

Screenshot:

Noticed the search bars are hidden behind the OverflowBox.

[ Provider Doc ] ChangeNotifier inside update

samples/provider_shopper/lib/main.dart

Line 32 in b7ec38a

CartModel(catalog, previousCart),

I was implementing a little test project with official Flutter doc about state management and looking at your awesome example. Thank you a lot btw.

While reading the ChangeNotifierProxyProvider documentation, I found this :

/// - **DON'T** create the [ChangeNotifier] inside `update` directly.
///
///   This will cause your state to be lost when one of the values used updates.
///   It will also cause uncesserary overhead because it will dispose the
///   previous notifier, then subscribes to the new one.
///
///  Instead reuse the previous instance, and update some properties or call
///  some methods.

So, if creating a new ChangeNotifier inside update callback is a bad practice as the doc says, you could change a bit the sample behavior here or add a little comment.