How do I write an android application

If you have not enough knowledge, this is fine: you can always learn the language, the platform, some general programming, all you need. Only you have to understand that learning it is the only way to get the solution. And searching for something is not an option. Especially when you don't properly formulate the problem.

If you have some specific problem which you can clearly formulate, we will gladly try to help.

—SA