Integrate Google Voice Recognition in Android app
Android can use voice recognition without any GUI. You can use SpeechRecognizer class to do this. But google doesn't allow you to use theirs voice tools for long time recognition. After 5-7 seconds of silence it will be stopped.
If you want to use limited comands vocabulary, you can use offline continious recognition like PocketSphinx.
For long time recognition you can use:
intent.putExtra("android.speech.extra.DICTATION_MODE", true);