Hi
1) For now, only X11 / OpenGL is supported for Linux. I don't know much about what Android uses, but I'd be glad to help you I you want to try porting SFML to this OS ![Smiley :)](https://www.sfml-dev.org/forums/Smileys/default/smiley.gif)
2) Probably in the future, but right now it's not in the roadmap.
3) This is an interesting feature, and I guess it's mandatory for multi-touch devices like the iPhone. So yes, SFML will support it one day.
1) From what I understand it uses Linux framebuffer, but all I have to support that is what I've found with google.
2) OK
3) Good, although I'd also have a use for it with computer gaming [multiplayer] too.
About Android. If I remember right, Google uses a modified version of Gnome Mobile for the Android System so I recommend that you use that API to work with the Mobile in order to get a good and compatible interface with the cellphone. Though it was long ago I read about Android so I might be wrong about GNOME.
Anyway I do know that Android hands a SDK specifically to develop applications for the Android OS. I think that is much more powerful than SFML or SDL if you want to develop for Android.
Thing with that is I'd also want to develop the same thing for the iPhone (which someone is already porting SFML too) and probably a prettier version for the computer. So simply using the system's own API instead of SFML would only make my project bigger than it needs to be.
And the Android SDK is for Java developers, and Android's default Java VM does not JIT compile; so if I want to make an application that demands at least decent performance then that is
definitely not the right path for me. Besides that, I haven't touched Java since I first started learning how to program, and I don't really want to touch it again as developing in it was not fun to me.