Is it possible in Android to open other App than the one you clicked on?

I am wondering if it is possible to intercept an open application 开发者_如何学Pythoncall, for any(most of the) installed application. Or at least for opening the Activity having the intent-filter's action set to Main (if it exists for an app).

No, sorry, this is not possible. The startActivity() calls are targeted to specific components and cannot be intercepted. After all, this would be a massive security hole otherwise.