I have a list of people in my app and when the user taps one of the list items, that person is called. Is it possible to hide the called number, so the person would be called but the number would't show in android dialer application and during the calling?
No. When you pass the Intent off to startActivity or startActivityForResult, the other activity has control until that activity exits. This is to prevent apps from making calls to 900 numbers without the user's knowledge.
来源：https://stackoverflow.com/questions/5969881/is-it-possible-to-hide-the-number-that-is-called-from-an-app