I have an application written in c, on Raspberry Pi, which starts in a sort of "waiting mode" and uses two buttons connected to the GPIO as "start" and "stop".
I was thinking about controlling it with an Android phone, and I found out the PiUi project.
Would it be possible to send commands to an active applications using PiUi?
Or there is a better solution?
Thanks to everyone that will help.
The PiUi interface is written and controlled in Python. This could be used to control your C program, but such interactivity won't happen magically. You will need to build some kind of listening interface into your C application. That could be done using message queues, shared memory, pipes, ports, or a number of other things.
It looks like PiUi is simply a framework for creating a local webpage. It may be simpler to just create one yourself as @SteveRobillard has suggested in the comments.