Where can I find a good example of a plugin architecture?
Roman Nurik from Google has implemented a nice plugins framework in his open source app dash clock. The plugins themselves are Services that extend the DashClockExtension class in the API and are installed as completely independent APK files with their own resources. It's quite a lot of work defining the communication protocol via the AIDL, but it's nice and clean and works very well.
one of the plugins must add a button on a particular screen, and clicking this button increments a value in the app's database.
The parts of the main Layout which can be modified by the plugin will need to be pre-defined by the core app, and exposed via the communication protocol. It should be possible for the plugin to inflate an arbitrary layout, and send it to the main app, which could put that inside a pre-allocated area of it's own Layout.
