Suppose I am in App1 and I want to open another app from my phone, App2, starting it with one of it's activities, SecondActivity. I need to do this with any of the apps that I have on my phone, so if I install new ones I need to be able to start them with any of their activity. I found this answer really useful, except from the fact that the activity I want to start with is declared in the manifest. If I have 10 installed apps with 10 activities each this solution doesn't help me at all.