Java “如何修复”；预期文件集合只包含一个文件，但它包含多个文件；

在我更新了Android Studio和Gradle之后，我无法构建我的项目。这只是突然出现。。。 我不知道这个错误是否发生在更早的时候，但我不这么认为，因为我的项目在上次编码时运行得很好

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:packageDebug'.
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:151)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:148)
    at org.gradle.internal.Try$Failure.ifSuccessfulOrElse(Try.java:191)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:141)
    at org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionStateTaskExecuter.execute(ResolveBeforeExecutionStateTaskExecuter.java:75)
    at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:62)
    at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:108)
    at org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionOutputsTaskExecuter.execute(ResolveBeforeExecutionOutputsTaskExecuter.java:67)
    at org.gradle.api.internal.tasks.execution.ResolveAfterPreviousExecutionStateTaskExecuter.execute(ResolveAfterPreviousExecutionStateTaskExecuter.java:46)
    at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:94)
    at org.gradle.api.internal.tasks.execution.FinalizePropertiesTaskExecuter.execute(FinalizePropertiesTaskExecuter.java:46)
    at org.gradle.api.internal.tasks.execution.ResolveTaskExecutionModeExecuter.execute(ResolveTaskExecutionModeExecuter.java:95)
    at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:57)
    at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:56)
    at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:36)
    at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.executeTask(EventFiringTaskExecuter.java:73)
    at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:52)
    at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:49)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:416)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:406)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute(DefaultBuildOperationExecutor.java:165)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:250)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:158)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:102)
    at org.gradle.internal.operations.DelegatingBuildOperationExecutor.call(DelegatingBuildOperationExecutor.java:36)
    at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter.execute(EventFiringTaskExecuter.java:49)
    at org.gradle.execution.plan.LocalTaskNodeExecutor.execute(LocalTaskNodeExecutor.java:43)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:355)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:343)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:336)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:322)
    at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute(DefaultPlanExecutor.java:134)
    at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute(DefaultPlanExecutor.java:129)
    at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.execute(DefaultPlanExecutor.java:202)
    at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.executeNextNode(DefaultPlanExecutor.java:193)
    at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.run(DefaultPlanExecutor.java:129)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.IllegalStateException: Expected file collection to contain exactly one file, however, it contains more than one file.
    at org.gradle.api.internal.file.AbstractFileCollection.getSingleFile(AbstractFileCollection.java:65)
    at com.android.build.gradle.internal.tasks.SigningConfigMetadata$Companion.getOutputFile(SigningConfigMetadata.kt:109)
    at com.android.build.gradle.tasks.PackageAndroidArtifact$SplitterParams.<init>(PackageAndroidArtifact.java:554)
    at com.android.build.gradle.tasks.PackageAndroidArtifact.lambda$doTaskAction$3(PackageAndroidArtifact.java:429)
    at com.android.build.gradle.internal.scope.BuildElements$WorkersBasedScheduler.transform(BuildElements.kt:154)
    at com.android.build.gradle.internal.scope.BuildElements$WorkersBasedScheduler.intoCallable(BuildElements.kt:143)
    at com.android.build.gradle.internal.scope.BuildElements$WorkersBasedScheduler.into(BuildElements.kt:138)
    at com.android.build.gradle.internal.scope.BuildElementActionScheduler.into(BuildElementActionScheduler.kt:37)
    at com.android.build.gradle.tasks.PackageAndroidArtifact.doTaskAction(PackageAndroidArtifact.java:432)
    at com.android.build.gradle.internal.tasks.NewIncrementalTask$taskAction$$inlined$recordTaskAction$1.invoke(AndroidVariantTask.kt:51)
    at com.android.build.gradle.internal.tasks.NewIncrementalTask$taskAction$$inlined$recordTaskAction$1.invoke(AndroidVariantTask.kt:31)
    at com.android.build.gradle.internal.tasks.Blocks.recordSpan(Blocks.java:91)
    at com.android.build.gradle.internal.tasks.NewIncrementalTask.taskAction(NewIncrementalTask.kt:34)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    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:103)
    at org.gradle.api.internal.project.taskfactory.IncrementalInputsTaskAction.doExecute(IncrementalInputsTaskAction.java:31)
    at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:41)
    at org.gradle.api.internal.project.taskfactory.AbstractIncrementalTaskAction.execute(AbstractIncrementalTaskAction.java:25)
    at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:28)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$5.run(ExecuteActionsTaskExecuter.java:404)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:402)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:394)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute(DefaultBuildOperationExecutor.java:165)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:250)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:158)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:92)
    at org.gradle.internal.operations.DelegatingBuildOperationExecutor.run(DelegatingBuildOperationExecutor.java:31)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:393)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:376)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.access$200(ExecuteActionsTaskExecuter.java:80)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$TaskExecution.execute(ExecuteActionsTaskExecuter.java:213)
    at org.gradle.internal.execution.steps.ExecuteStep.lambda$execute$0(ExecuteStep.java:32)
    at java.util.Optional.map(Optional.java:215)
    at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:32)
    at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:26)
    at org.gradle.internal.execution.steps.CleanupOutputsStep.execute(CleanupOutputsStep.java:58)
    at org.gradle.internal.execution.steps.CleanupOutputsStep.execute(CleanupOutputsStep.java:35)
    at org.gradle.internal.execution.steps.ResolveInputChangesStep.execute(ResolveInputChangesStep.java:48)
    at org.gradle.internal.execution.steps.ResolveInputChangesStep.execute(ResolveInputChangesStep.java:33)
    at org.gradle.internal.execution.steps.CancelExecutionStep.execute(CancelExecutionStep.java:39)
    at org.gradle.internal.execution.steps.TimeoutStep.executeWithoutTimeout(TimeoutStep.java:73)
    at org.gradle.internal.execution.steps.TimeoutStep.execute(TimeoutStep.java:54)
    at org.gradle.internal.execution.steps.CatchExceptionStep.execute(CatchExceptionStep.java:35)
    at org.gradle.internal.execution.steps.CreateOutputsStep.execute(CreateOutputsStep.java:51)
    at org.gradle.internal.execution.steps.SnapshotOutputsStep.execute(SnapshotOutputsStep.java:45)
    at org.gradle.internal.execution.steps.SnapshotOutputsStep.execute(SnapshotOutputsStep.java:31)
    at org.gradle.internal.execution.steps.CacheStep.executeWithoutCache(CacheStep.java:201)
    at org.gradle.internal.execution.steps.CacheStep.execute(CacheStep.java:70)
    at org.gradle.internal.execution.steps.CacheStep.execute(CacheStep.java:45)
    at org.gradle.internal.execution.steps.BroadcastChangingOutputsStep.execute(BroadcastChangingOutputsStep.java:49)
    at org.gradle.internal.execution.steps.StoreSnapshotsStep.execute(StoreSnapshotsStep.java:43)
    at org.gradle.internal.execution.steps.StoreSnapshotsStep.execute(StoreSnapshotsStep.java:32)
    at org.gradle.internal.execution.steps.RecordOutputsStep.execute(RecordOutputsStep.java:38)
    at org.gradle.internal.execution.steps.RecordOutputsStep.execute(RecordOutputsStep.java:24)
    at org.gradle.internal.execution.steps.SkipUpToDateStep.executeBecause(SkipUpToDateStep.java:96)
    at org.gradle.internal.execution.steps.SkipUpToDateStep.lambda$execute$0(SkipUpToDateStep.java:89)
    at java.util.Optional.map(Optional.java:215)
    at org.gradle.internal.execution.steps.SkipUpToDateStep.execute(SkipUpToDateStep.java:54)
    at org.gradle.internal.execution.steps.SkipUpToDateStep.execute(SkipUpToDateStep.java:38)
    at org.gradle.internal.execution.steps.ResolveChangesStep.execute(ResolveChangesStep.java:77)
    at org.gradle.internal.execution.steps.ResolveChangesStep.execute(ResolveChangesStep.java:37)
    at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsFinishedStep.execute(MarkSnapshottingInputsFinishedStep.java:36)
    at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsFinishedStep.execute(MarkSnapshottingInputsFinishedStep.java:26)
    at org.gradle.internal.execution.steps.ResolveCachingStateStep.execute(ResolveCachingStateStep.java:90)
    at org.gradle.internal.execution.steps.ResolveCachingStateStep.execute(ResolveCachingStateStep.java:48)
    at org.gradle.internal.execution.impl.DefaultWorkExecutor.execute(DefaultWorkExecutor.java:33)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:120)
    ... 38 more

org.gradle.api.tasks.TaskExecutionException:任务：app:packageDebug的执行失败。
位于org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept（ExecuteActionsTaskExecuter.java:151）
位于org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept（ExecuteActionsTaskExecuter.java:148）
位于org.gradle.internal.Try$Failure.ifSuccessfulOrElse（Try.java:191）
位于org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute（ExecuteActionsTaskExecuter.java:141）
位于org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionStateTaskExecuter.execute（ResolveBeforeExecutionStateTaskExecuter.java:75）
位于org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute（ValidatingTaskExecuter.java:62）
位于org.gradle.api.internal.tasks.execution.skipmptysourcefilestaskexecuter.execute（skipmptysourcefilestaskexecuter.java:108）
位于org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionOutputsTaskExecuter.execute（ResolveBeforeExecutionOutputsTaskExecuter.java:67）
位于org.gradle.api.internal.tasks.execution.ResolveAfterPreviousExecutionStateTaskExecuter.execute（ResolveAfterPreviousExecutionStateTaskExecuter.java:46）
位于org.gradle.api.internal.tasks.execution.cleanupstaleoutputsecuter.execute（cleanupstaleoutputsecuter.java:94）
位于org.gradle.api.internal.tasks.execution.FinalizePropertiesTaskExecuter.execute（FinalizePropertiesTaskExecuter.java:46）
位于org.gradle.api.internal.tasks.execution.ResolveTaskExecutionModeExecuter.execute（ResolveTaskExecutionModeExecuter.java:95）
位于org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute（SkipTaskWithNoActionsExecuter.java:57）
位于org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute（SkipOnlyIfTaskExecuter.java:56）
位于org.gradle.api.internal.tasks.execution.catchExceptionTaskKexecuter.execute（catchExceptionTaskKexecuter.java:36）
位于org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.executeTask（EventFiringTaskExecuter.java:73）
位于org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call（EventFiringTaskExecuter.java:52）
位于org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call（EventFiringTaskExecuter.java:49）
位于org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute（DefaultBuildOperationExecutor.java:416）
位于org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute（DefaultBuildOperationExecutor.java:406）
位于org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute（DefaultBuildOperationExecutor.java:165）
位于org.gradle.internal.operations.DefaultBuildOperationExecutor.execute（DefaultBuildOperationExecutor.java:250）
位于org.gradle.internal.operations.DefaultBuildOperationExecutor.execute（DefaultBuildOperationExecutor.java:158）
位于org.gradle.internal.operations.DefaultBuildOperationExecutor.call（DefaultBuildOperationExecutor.java:102）
在org.gradle.internal.operations.DelegatingBuildOperationExecutor.call（DelegatingBuildOperationExecutor.java:36）
位于org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter.execute（EventFiringTaskExecuter.java:49）
位于org.gradle.execution.plan.LocalTaskNodeExecutor.execute（LocalTaskNodeExecutor.java:43）
位于org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute（DefaultTaskExecutionGraph.java:355）
位于org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute（DefaultTaskExecutionGraph.java:343）
在org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$buildOperationaWareeExecutionAction.execute（DefaultTaskExecutionGraph.java:336）
位于org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$buildOperationaWareeExecutionAction.execute（DefaultTaskExecutionGraph.java:322）
位于org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute（DefaultPlanExecutor.java:134）
位于org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute（DefaultPlanExecutor.java:129）
位于org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.execute（DefaultPlanExecutor.java:202）
位于org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.executeNextNode（DefaultPlanExecutor.java:193）
位于org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.run（DefaultPlanExecutor.java:129）
位于org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute（ExecutorPolicy.java:63）
位于org.gradle.internal.concurrent.ManagedExecutorImpl$1.run（ManagedExecutorImpl.java:46）
位于java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1149）
位于java.util.concurrent.ThreadPoolExecutor$Worker.run（ThreadPoolExecutor.java:624）
位于org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run（ThreadFactoryImpl.java:55）
运行（Thread.java:748）
导致：java.lang.IllegalStateException:预期文件集合只包含一个文件，但它包含多个文件。
位于org.gradle.api.internal.file.AbstractFileCollection.getSingleFile（AbstractFileCollection.java:65）
位于com.android.build.gradle.internal.tasks.SigningConfigMetadata$Companion.getOutputFile（SigningConfigMetadata.kt:109）
位于com.android.build.gradle.tasks.PackageAndroidArtifact$SplitterParams。（PackageAndroidArtifact.java:554）
位于com.android.build.gradle.tasks.PackageAndroidArtifact.lambda$doTaskAction$3（PackageAndroidArtifact.java:429）
在com.android.build.gradle.internal.scope.BuildElements$Workers上
Execution failed for task ':app:packageDebug'. > Expected file collection to contain exactly one file, however, it contains more than one filed