Okay, this is a bit much to post in a comment, so here's what you need to do with setDataSource(). If you check the docs for setDataSource() you'll see that it requires a FileDescriptor . You can acquire one for a Raw resource like so.
From your code, it looks like you are creating MediaPlayer on click. But I don't see any code to stop / release it. So your application may be running out of resources, finally stopping additional media player content.
That is why after couple of shake events, this issue is propping up.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.