Warning:com.morgoo.droidplugin.hook.proxy.IActivityManagerHook$1: can't find superclass or interface android.util.Singleton
Warning:com.morgoo.droidplugin.hook.proxy.IActivityManagerHook$1: can't find referenced class android.util.Singleton
Warning:there were 4 unresolved references to classes or interfaces.
Warning:Exception while processing task java.io.IOException: Please correct the above warnings first.
Error:Execution failed for task ':app:transformClassesAndResourcesWithProguardForRelease'.
> java.io.IOException: Please correct the above warnings first.
打包apk時，build apk沒有問題，但是選擇generate signed APK則報以上錯，看了Android Studio實現代碼混淆這篇文章之後，在
proguard-rules.pro 中加入
-dontwarn com.morgoo.droidplugin.hook.proxy.**
-keep class com.morgoo.droidplugin.hook.proxy.** { *;}
問題解決