Android implements incoming call mute example (listening incoming calls)

/**
* Incoming call silent
 *
 * @param context
 */
private void toggleRingerMute(Context context)
{
    AudioManager am = (AudioManager) (Context.AUDIO_SERVICE);
    if (previousMuteMode == -1)
    {
        previousMuteMode = ();
        (0);
    }
    (previousMuteMode);
    previousMuteMode = -1;
}