我已经开始使用Android Studio（版本3.1.2）并学习Android开发大约一周了，从第一天开始，IDE就会在它感觉到的时候不断抛出随机异常。 抛出的异常都不会影响我的工作流程并且IDE保持正常工作（至少看起来如此）。 异常的类型可能因时而异，但最常见的是下面的那种。通过在线查询，我得到的结果来自那些在代码中有错误或正在使用日志库的人。 这些都不是我的情况。那为什么会这样呢？
Stub index points to a file without PSI: com.intellij.openapi.fileTypes.UnknownFileType@6e0b0e23
com.intellij.openapi.diagnostic.Logger$EmptyThrowable
at com.intellij.openapi.diagnostic.Logger.error(Logger.java:140)
at com.intellij.psi.stubs.StubProcessingHelperBase.processStubsInFile(StubProcessingHelperBase.java:47)
at com.intellij.psi.stubs.StubIndexImpl$2.process(StubIndexImpl.java:327)
at com.intellij.psi.stubs.StubIndexImpl$StubIdListContainerAction.perform(StubIndexImpl.java:618)
at com.intellij.psi.stubs.StubIndexImpl$StubIdListContainerAction.perform(StubIndexImpl.java:606)
at com.intellij.util.indexing.ValueContainer.forEach(ValueContainer.java:62)
at com.intellij.psi.stubs.StubIndexImpl.doProcessStubs(StubIndexImpl.java:356)
at com.intellij.psi.stubs.StubIndexImpl.processElements(StubIndexImpl.java:319)
at com.intellij.psi.stubs.StubIndex.getElements(StubIndex.java:145)
at com.intellij.psi.stubs.StubIndex.getElements(StubIndex.java:134)
at com.intellij.psi.impl.java.stubs.index.JavaShortClassNameIndex.get(JavaShortClassNameIndex.java:53)
at com.intellij.psi.impl.PsiShortNamesCacheImpl.getClassesByName(PsiShortNamesCacheImpl.java:63)
at com.intellij.psi.impl.CompositeShortNamesCache.getClassesByName(CompositeShortNamesCache.java:77)
at com.intellij.psi.impl.search.AllClassesSearchExecutor.lambda$processClassesByNames$1(AllClassesSearchExecutor.java:82)
at com.intellij.openapi.project.DumbService.lambda$runReadActionInSmartMode$0(DumbService.java:94)
at com.intellij.openapi.project.DumbService.runReadActionInSmartMode(DumbService.java:125)
at com.intellij.openapi.project.DumbService.runReadActionInSmartMode(DumbService.java:94)
at com.intellij.psi.impl.search.AllClassesSearchExecutor.processClassesByNames(AllClassesSearchExecutor.java:82)
at com.intellij.codeInsight.completion.AllClassesGetter.processJavaClasses(AllClassesGetter.java:150)
at com.intellij.codeInsight.completion.AllClassesGetter.processJavaClasses(AllClassesGetter.java:136)
at com.intellij.codeInsight.completion.JavaClassNameCompletionContributor.addAllClasses(JavaClassNameCompletionContributor.java:142)
at com.intellij.codeInsight.completion.JavaNoVariantsDelegator.suggestNonImportedClasses(JavaNoVariantsDelegator.java:186)
at com.intellij.codeInsight.completion.JavaNoVariantsDelegator.fillCompletionVariants(JavaNoVariantsDelegator.java:76)
at com.intellij.codeInsight.completion.CompletionService.getVariantsFromContributors(CompletionService.java:83)
at com.intellij.codeInsight.completion.CompletionResultSet.runRemainingContributors(CompletionResultSet.java:149)
at com.intellij.codeInsight.completion.CompletionResultSet.runRemainingContributors(CompletionResultSet.java:142)
at com.intellij.codeInsight.completion.JShellCompletionContributor.fillCompletionVariants(JShellCompletionContributor.java:28)
at com.intellij.codeInsight.completion.CompletionService.getVariantsFromContributors(CompletionService.java:83)
at com.intellij.codeInsight.completion.CompletionResultSet.runRemainingContributors(CompletionResultSet.java:149)
at com.intellij.codeInsight.completion.CompletionResultSet.runRemainingContributors(CompletionResultSet.java:142)
at com.intellij.codeInsight.template.impl.LiveTemplateCompletionContributor$2.addCompletions(LiveTemplateCompletionContributor.java:90)
at com.intellij.codeInsight.completion.CompletionProvider.addCompletionVariants(CompletionProvider.java:36)
at com.intellij.codeInsight.completion.CompletionContributor.fillCompletionVariants(CompletionContributor.java:152)
at com.intellij.codeInsight.completion.CompletionService.getVariantsFromContributors(CompletionService.java:83)
at com.intellij.codeInsight.completion.CompletionService.performCompletion(CompletionService.java:112)
at com.intellij.codeInsight.completion.CompletionProgressIndicator.calculateItems(CompletionProgressIndicator.java:839)
at com.intellij.codeInsight.completion.CompletionProgressIndicator.access$600(CompletionProgressIndicator.java:92)
at com.intellij.codeInsight.completion.CompletionProgressIndicator$1CalculateItems.run(CompletionProgressIndicator.java:821)
at com.intellij.openapi.application.impl.ApplicationImpl.tryRunReadAction(ApplicationImpl.java:1130)
at com.intellij.codeInsight.completion.AsyncCompletion.tryReadOrCancel(CompletionThreading.java:181)
at com.intellij.codeInsight.completion.CompletionProgressIndicator.lambda$startCompletion$6(CompletionProgressIndicator.java:832)
at com.intellij.codeInsight.completion.AsyncCompletion.lambda$null$0(CompletionThreading.java:108)
at com.intellij.openapi.progress.impl.CoreProgressManager.lambda$runProcess$1(CoreProgressManager.java:157)
at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:543)
at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:488)
at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:94)
at com.intellij.openapi.progress.impl.CoreProgressManager.runProcess(CoreProgressManager.java:144)
at com.intellij.codeInsight.completion.AsyncCompletion.lambda$startThread$1(CompletionThreading.java:104)
at com.intellij.openapi.application.impl.ApplicationImpl$1.run(ApplicationImpl.java:315)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
答案 0 :(得分：0)
我遇到了同样的问题并且缓存无效，重新启动解决了它。
File -> Invalidate Caches / Restart -> Invalidate and Restart。