Polazil in Google, did not find a solution. The bottom line is that you need to associate your file format with your application. Click on the format opens the application. I would be grateful for at least something (where to dig)
Well, it's better to look in English: https://stackoverflow.com/questions/3760276/android-intent-filter-associate-app-with-file-extension
On the whole, @rasmisha correctly noticed. Add filters to your main activity and write processing logic. I suspect that in the Bundle (in the onCreate parameter of your main activation) there will be corresponding parameters for the file: location, name, and so on. But in any case, this information you also need.