Question

Is there any sample application which demonstrates the capabilities of Telephony API of android? I am interested in getting the call notifications / caller number etc(I understand its doable with PhoneStateListener). Also, Is it possible for 3rd party application to change the incoming call window / outgoing call window (basically to give the user an extra button to search the incoming number from a REST service) ?

Any useful links or sample application would be very much helpful. Any suggestions ?

Answer 1

PhoneStateListener tells your app about phone activity. Here’s some sample code from one of my apps that pauses music when the phone is active:

/**
 * Helper class to pause music while a phone call is in progress.
 * 
 * The Android emulator can simulate an outgoing call by clicking
 * the phone button and dialing normally.  Simulate an incoming call
 * by starting the emulator, "telnet localhost 5554" then enter 
 * "gsm call 5551234" into the telnet session.  
 */
private class MusicServicePhoneStateListener extends PhoneStateListener {
    private boolean mResumeAfterCall = false;

    @Override
    public void onCallStateChanged(int state, String incoming_number) {
        switch (state) {
        case TelephonyManager.CALL_STATE_OFFHOOK:
        case TelephonyManager.CALL_STATE_RINGING:
            Log.i(tag, "phone active, suspending music service");
            mResumeAfterCall = mMediaPlayer.isPlaying();
            mMediaPlayer.pause();
            break;
        case TelephonyManager.CALL_STATE_IDLE:
            Log.i(tag, "phone inactive, resuming music service");
            if (mResumeAfterCall) {
                mMediaPlayer.start();
            }
            break;
        default:
            break;
        }
    }
}

Create and start the listener in onCreate via:

    mPhoneListener = new MusicServicePhoneStateListener();
    ((TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE)).listen(mPhoneListener, PhoneStateListener.LISTEN_CALL_STATE);

Stop the listener in onDestroy with:

    ((TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE)).listen(mPhoneListener, 0);

As for modifying the incoming call dialog the best suggestion I’ve found is to use a short delay followed by a custom toast message (delay so that your toast appears “above” the incoming call dialog).