Android app x11 forwarding to computer
What you're trying to do is not possible. Android has its own windowing system, not X11, so X forwarding won't do anything on Android.

There are other screen-sharing systems (such as VNC) which might be more suitable for what you're trying to do. This answer talks about a Samsung-specific app, and this question has a couple of options. The remote-access and remote-control tags have a lot more information.