Android Question How to record call and other queries?

Hello,

I need to implement following features in my mobile app:

1. Load a list of phone numbers from a file which is received through email
2. Dial the numbers one by one
3. When the number is dialed it should not show on screen and during the call I need to show another screen in which user (caller) will select various options based of called person's feedback
   
4. Record the conversation and save to a mp3 file
5. Once the call is over delete the call information from call log of phone

From above I have managed to complete features 1, 2 and 5.

I am not able to hide the dialing when the number is getting dialed through phone dialer. Can we hide this get the phone to dial a number in background?

Due to limitation of my knowledge I am not able to record the call though there are many ready to use call recording app on play store. Any idea as to how to achieve this?

I am not able to detect perfectly as to when the call gets disconnected as well as when a number being dialed is busy or has rejected the call.

Gurus on this forum please help.

Regards,

Yogesh