Implementation of a dialing program through the earphone button

Hello, everyone

Using the Play / Vol + / Vol - / Stop button on the earphone

Dial the specified number of phone number when the play button is pressed

Dial the specified number of phone number 2 when the Vol + button is pressed

Vol - Dial the specified phone number when the button is pressed

End the call when the stop button is pressed We're going to use Android Studio to create a simple program that works like this I'm going to make it.

I looked up the materials on the Internet, but it was hard to understand clearly Post the question.

The API tries to use 2.3 Ginger Bread.

How is it efficient to make a code to get that input when you press a button? If you know any information or code samples related to this, please help.