关于安卓与unity开发中,AAR的报的一个错误

错误：IOException: Failed to Copy File / Directory from ‘Temp/StagingArea\android-libraries\xflibrary-debug\classes.jar’ to ‘Temp/StagingArea\android-libraries\xflibrary-debug\libs\classes.jar’: destination path already exists.
UnityEditor.FileUtil.MoveFileOrDirectory (System.String source, System.String dest) (at D:/unity/artifacts/generated/common/editor/FileUtilBindings.gen.cs:74)
UnityEditor.Android.PostProcessor.Tasks.ProcessAAR.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessAndroidPlayer.PostProcess (BuildTarget target, System.String stagingAreaData, System.String stagingArea, System.String playerPackage, System.String installPath, System.String companyName, System.String productName, BuildOptions options
错误原因：我把AAR包 —>libs里的classes.jar包删除了，把ARR里、不在libs文件夹里的那个classes.jar包拖进libs文件夹里。以前这么做是正确的，现在这么做是错误的。