org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:compileDebugJavaWIThJavac'.     at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:100)     at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:70)     at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)     at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:62)     at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingstateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)     at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:60)     at org.gradle.api.internal.tasks.execution.SkiPEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:97)     at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:87)     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$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)     at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)     at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)     at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:241)     at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:230)     at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:123)     at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:79)     at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:104)     at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:98)     at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:626)     at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:581)     at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)     at org.gradle.internal.concurrent.Executorpolicy$CatchAndRecorDFailures.onExecute(ExecutorPolicy.java:63)     at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)     at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)     at java.lang.Thread.run(Thread.java:745)

在AndROIdStudio(mac os)的terminal中输入命令

./gradlew compileDebug --stacktrace

windows下输入

gradlew compileDebug --stacktrace

查看日志

    * What went wrong: Task 'compileDebug' is amBiguous in root project 'defineViewStudy'. Candidates are: 'compileDebugAidl', 'compileDebugAndroidtestAidl', 'compileDebugAndroidTestJavaWithJavac', 'compileDebugAndroidTestNdk', 'compileDebugAndroidTestRenderscript', 'compileDebugAndroidTestShaders', 'compileDebugAndroidTestSources', 'compileDebugJavaWithJavac', 'compileDebugNdk', 'compileDebugRenderscript', 'compileDebugShaders', 'compileDebugSources', 'compileDebugUnitTestJavaWithJavac', 'compileDebugUnitTestSources'.  * Try: Run gradlew tasks to get a list of available tasks. Run with --info or --debug option to get more LOG output. Run with --scan to get full insights.  * Exception is: org.gradle.execution.TaskSelectionException: Task 'compileDebug' is ambiguous in root project 'DefineViewStudy'. Candidates are: 'compileDebugAidl', 'compileDebugAndroidTestAidl', 'compileDebugAndroidTestJavaWithJavac', 'compileDebugAndroidTestNdk', 'compileDebugAndroidTestRenderscript', 'compileDebugAndroidTestShaders', 'compileDebugAndroidTestSources', 'compileDebugJavaWithJavac', 'compileDebugNdk', 'compileDebugRenderscript', 'compileDebugShaders', 'compileDebugSources', 'compileDebugUnitTestJavaWithJavac', 'compileDebugUnitTestSources'. 

注意到这句话Task 'compileDebug' is ambiguous in root project 'DefineViewStudy'. 单词
ambiguous是模糊不清的意思.尝试着把命令改为

./gradlew compileDebugJavaWithJavac

windows下输入

gradlew compileDebugJavaWithJavac

这次打印的信息很明了了.

    /Users/xxx/work/workspace/github/DefineViewStudy/app/src/main/java/com/idealcn/define/view/ui/MainFragment.java:70: 错误: 找不到符号             case R.id.round_cake:                      ^   符号:   变量 round_cake   位置: 类 id /Users/guoning/work/workspace/github/DefineViewStudy/app/src/main/java/com/idealcn/define/view/ui/MainFragment.java:74: 错误: 找不到符号             case R.id.Drag:                      ^   符号:   变量 drag   位置: 类 id 注: 某些输入文件使用或覆盖了已过时的 API。 注: 有关详细信息, 请使用 -Xlint:deprecation 重新编译。 2 个错误

原来是view的id找不到了.彻底解决了!

可以在Android-studio右侧找到gradlew对应的各种快捷键