Flutterサンプルを動かすのにFailed to execute aaptが出た

# はじめに
ここ↓を参考に、いくつかサンプルを動かそうと思って
https://qiita.com/ikemura23/items/255a6980c57afd0f3856

ここ↓のjsonexampleを試してみようと思い、クローン
https://github.com/flutter/samples/blob/master/INDEX.md

そしてrun

```
/Users/user/.gradle/caches/transforms-1/files-1.1/support-compat-28.0.0.aar/80283d6ca3ee3c256d26009235bbdbbe/res/values/values.xml:133:5-70: AAPT: error: resource android:attr/fontVariationSettings not found.

/Users/user/.gradle/caches/transforms-1/files-1.1/support-compat-28.0.0.aar/80283d6ca3ee3c256d26009235bbdbbe/res/values/values.xml:133:5-70: AAPT: error: resource android:attr/ttcIndex not found.

/Users/user/Downloads/samples-master/jsonexample/build/app/intermediates/incremental/mergeDebugResources/merged.dir/values/values.xml:84: error: resource android:attr/fontVariationSettings not found.
/Users/user/Downloads/samples-master/jsonexample/build/app/intermediates/incremental/mergeDebugResources/merged.dir/values/values.xml:84: error: resource android:attr/ttcIndex not found.
error: failed linking references.

Failed to execute aapt
com.android.ide.common.process.ProcessException: Failed to execute aapt
	at com.android.builder.core.AndroidBuilder.processResources(AndroidBuilder.java:796)
	at com.android.build.gradle.tasks.ProcessAndroidResources.invokeAaptForSplit(ProcessAndroidResources.java:551)
	at com.android.build.gradle.tasks.ProcessAndroidResources.doFullTaskAction(ProcessAndroidResources.java:285)
	at com.android.build.gradle.internal.tasks.IncrementalTask.taskAction(IncrementalTask.java:109)
	at sun.reflect.GeneratedMethodAccessor655.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
	at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$IncrementalTaskAction.doExecute(DefaultTaskClassInfoStore.java:173)
	at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$StandardTaskAction.execute(DefaultTaskClassInfoStore.java:134)
	at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$StandardTaskAction.execute(DefaultTaskClassInfoStore.java:121)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:122)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:197)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:107)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:111)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:92)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:70)
	at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:63)
	at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
	at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
	at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:88)
	at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:52)
	at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
	at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54)
	at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
	at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34)
	at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:248)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:197)
	at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:107)
・
・
・
```

**あああああああああああサンプルはそのまま動くようにしとけやあああああああ**

# 環境
Android Studio3.5
**Flutter 1.10.6 (dev channel)**
Dart 2.6.0

# 試行錯誤
ここ↓とか参考に色々試してみるも、うまくいかない。
https://github.com/flutter/flutter/issues/27106

```android/build.gradle
-subprojects {
-    project.evaluationDependsOn(':app')
-}
```
変わらず

```gradle.properties
+android.useAndroidX=true
+android.enableJetifier=true
```
変わらず

詰む。

# おや？

channelが・・・devになっている。

```
(base) MacBook-Pro:jsonexample user$ flutter channel
Flutter channels:
  beta
* dev
  master
  stable
```

sbableに変えて

```
(base) MacBook-Pro:jsonexample user$ flutter channel stable
Switching to flutter channel 'stable'...
git: From https://github.com/flutter/flutter
git:    104445722..b07056b10  master     -> origin/master
git: Switched to branch 'stable'
git: Your branch is up to date with 'origin/stable'.
```

upgradeする

```
(base) MacBook-Pro:jsonexample user$ flutter upgrade
```

そしてrun

```
Running "flutter pub get" in jsonexample... 
```

上がった！
<img width="332" alt="スクリーンショット 2019-09-27 11.49.05.png" src="https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/248187/0d57f5b1-4b52-38f5-966e-cf7e67167596.png">

# まとめ
**サンプルに文句をいう前に環境を見直そう。（ATARIMAE）** 

2019/9/27現在のFlutterのstableは1.9です。
サンプルプロジェクトにも1.9対応済みが最新のコミットになってました。

Flutter単体ではdevでも大丈夫であっても、使ってるpluginとかの兼ね合いもあるので、
特にとりあえずサンプル動かす！という時はstable一択ですね。
もちろん開発としてがっつり使うときもそれはそれで当然stable一択なワケですが。

自分への戒めとしてここに記録しておきます。