I'm currently developing a custom SystemUI for Android, so I have no permission Problems.
I want a "Mediaplayer Widget" like on the Lockscreen. I think I can easily control the default Mediaplayer (or any Mediaplayer?) by injecting KeyEvents to the System.
My Problem is: How can I ensure to get updated about songchanges and opening/closing the Mediaplayer?.
Update
I found the Source of the ScreenLock and found the Code for IRemoteControlDisplay but now I dont't know how to use it. I tried to Debug it and it appears, that right after initalization, the onListenerDetached method gets called twice...