When creating a APK with proguard enabled, the following exception is thrown when using the FirebaseRecyclerAdapter from the Firebase-UI library (com.firebaseui:fireba
Solved this by moving the ViewHolder classes that are used by the FirebaseRecyclerAdapter to a dedicated package (e.g. com.mypackage.myapp.viewholders) and adding a rule within the proguard configuration to prevent that classes within this package become obfuscated by proguard:
-keep class com.mypackage.myapp.viewholders.** { *; }