How to change vibrate mode to ringer prgrammatically through audio manager

Question

I am making application where phone mode will changes from silent mode to ringer mode if the user sends an sms with some specific keyword. The application mainly works when

Answer 1

set SILENT mode to Normal mode using AudioManager

AudioManager am = (AudioManager)getSystemService(Context.AUDIO_SERVICE);   

switch (am.getRingerMode()) {   
    case AudioManager.RINGER_MODE_SILENT:   
        Log.i("MyApp","Silent mode");
        am.setRingerMode(AudioManager.RINGER_MODE_NORMAL);
        break;   
}