Hi There I'm looking to create a custom call application.
i.e I want to replace the default application handling call :S.
I'M SURE THAT I WANT TO REINVENT THE WHEEL Sometimes current wheels are ain't good for me.
Can you put me on a start up line. I used to be a married to M$ ".net developer", and I'm in love with gOOgle.
As Emmanuel has already stated, it is not possible to truly replace the phone app without recompiling the operating system. Even on a rooted device, you are still locked into the vendor firmware and trying to work backwards from there would be a tenuous proposition at best. Now, it is possible to receive notifications in certain event types and preform actions there, but I doubt this is what you want to do.
However, for those who must know what goes on under the hood, take a look here
For exposed telephony interface (including SMS API), see android.telephony
Now it is possible. From the documentation page Build a calling app:
Build a calling app
A calling app allows users to receive or place audio or video calls on their device. Calling apps use their own user interface for the calls instead of using the default Phone app interface...
The Android framework includes the android.telecom package, which contains classes that help you build a calling app according to the telecom framework. ...
Your app manifest must declare that it uses all the appropriate permissions (currently MANAGE_OWN_CALLS, READ_CALL_LOG, READ_PHONE_STATE, and READ_PHONE_NUMBERS) and implement the ConnectionService and Connection classes.
The aforementioned doc page provide further details and examples.
It's not possible to replace the phone application besides making a custom operating system and install it on rooted phones. But that's a lot of trouble.
But you can develop a separate application and have it make phone calls or intercept incoming calls. But while the user is talking on phone he'll still see the old phone application.
