Hello, I have created an application that dynamically loads plugin style functionality using a DexClassLoader. My application is organized as follows:
- Interface.jar, which defines the interfaces of the plugin classes. - Implementation.jar, which contains classes that implement the plugin interfaces, and are compiled into a classes.dex file. - MyApp.apk, which loads the plugin implementation at runtime using a DexClassLoader and reflection. This APK is compiled with Interface.jar, so that the implementation objects that are created with reflection can be casted to interface objects and used normally. This all works great, until I want to extend my interface. I would like to be able to, say add functionality to an interface Foo by creating interface Foo2 which extends Foo. I could release a new plugin that implements Foo2 to all of my clients, and those that are new enough to know about Foo2 can use that interface while the older ones just use Foo. I believe this is a pretty common pattern for plugins outside of Android. But I am having a problem with how I compile the new interface classes into my plugin. If I compile Interface.jar into Implementation.jar, when I use the DexClassLoader to load the implementation classes I get the error "java.lang.IllegalAccessError: Class ref in pre-verified class resolved to unexpected implementation". This happens even if I haven't extended the interface, so I initially just compiled Implementation.jar without Interface.jar. I believe this is the Dalvik VM complaining that it now has to definitions for the same class. But, if I don't include the new Interface.jar, when an old client tries to dynamically instantiate a class that implements Foo2, I will get a ClassNotFoundException because there will be no definition for Foo2. Am I doing something wrong? I feel like I can't be the only person that is trying to design an extensible plugin framework like this on Android, but I can't find any information on how to get this to work. Thanks in advance for any help. -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
