This document discusses implementing voice recognition in an Android game. It covers using the Android speech API and IME to integrate voice commands. Commands are handled continuously to control the game. Limitations include potential recognition inaccuracies and that voice is not a suitable input for all.

1. Move as I speak
Understanding the development of a game that is controlled through
voice commands

2. Agenda
Voice recognition in android
Implementing Voice recognition in android
 Using Android speech input API
 Using IME
Integrating Voice recognition in the Game
Controlling the Game through voice commands
Limitations

3. Voice Recognition in Android

4. Voice Recognition in Android
 Available in android since Android 1.5 .
 voice recognition can be used only when connected to the internet
until Android 4.0.X(ICS) .
 Voice sent to the cloud which returns an array of results .
 Voice recognition is available in offline mode in Android 4.1(Jelly
bean) .
 English(US) is given as default language and many other languages
are available for download.

5. Google’s Speech Recognizer
Google’s Speech Recognizer
Google speech ser ver !
Japanese! US English! …!
Acoustic Dictionar y! Acoustic Dictionar y!
Model! Model!
Search Dictation Search Dictation
Language Language Language Language
Model! Model! Model! Model!

6. Implementing Voice
Recognition in Android

7. Android Speech Input API
 Android’s open platform makes it simple
to access Google’s speech recognizer
programmatically from your
application(or any other recognizer that
registers for RecognizerIntent)
 Simple to Use the API to:
• Prompt the user to start speaking,
• Stream the audio Google's Servers,
• Retrieve the recognition hypothesis

8. Example Code
//called when someone clicks on a button in the app
public void onClick(View v) {
// create a recognition request
Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
// Set the language model
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
// Send the request to display propmpt, record audio, and return a result
intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "Speech recognition demo");
startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);
}
// Called when speech recognition is finished
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
//Get the n-best list
ArrayList<String> matches = data.getStringArrayListExtra(
RecognizerIntent.EXTRA_RESULTS);
//Do something with best result
DoSomething(matches.get(bestResult));
}

9. Parameters
 Language(EXTRA_LANGUAGE), e.g
• Ja_jp (Japanese)
• en_us (US English)
 If not set ,then the phones default language is
used.
 Language Model
hints(EXTRA_LANGUAGE_MODEL)
• Search - Good for short queries, business names,
cities. The types of things people search for on
Google.
• Free Form - For dictation . Sending e-mail, SMS, etc.

10. Using IME
public void onCreate() {
super.onCreate();
// Create the voice recognition trigger
// The trigger has to unregistered, when the IME is destroyed.
mVoiceRecognitionTrigger = new VoiceRecognitionTrigger(this);
//register the listener.
mVoiceRecognitionTrigger.register(new VoiceRecognitionTrigger.Listener() {
@Override
public void onVoiceImeEnabledStatusChange() {
// The call back is done on the main thread.
updateVoiceImeStatus();
}
});
}

11. Using IME
// Use this method to start voice recognition.
mVoiceRecognitionTrigger.startVoiceRecognition(“en_us”);
public void onDestroy() {
if (mVoiceRecognitionTrigger != null) {
// To avoid service leak, the trigger has to be unregistered
//when the IME is destroyed.
mVoiceRecognitionTrigger.unregister(this);
}
super.onDestroy();
}

12. Integrating Voice recognition
in the Game
 Google voice API can not be used for a
game because an intent has to be fired
every time to fetch the results for every
voice command.
 IME
has to be used which provides
continuous feed back of the voice
commands to the application.

13. Controlling the game through
Voice commands
// Called when speech recognition is finished
protected void onActivityResult(int requestCode, int resu
ltCode, Intent data) {
//Get the n-best list
ArrayList<String> matches = data.getStringArrayListE
xtra(RecognizerIntent.EXTRA_RESULT);
//store the best result into a variable which is used as a
command in the game
voiceRecognizer.command=matches.get(bestResult))
;

14. Controlling the game through
Voice commands
// Method which is used to render . This method is called
continuously in the game
public void animRender(Canvas c)
{
String voiceCommand = voiceRecognizer.command;
if(voiceCommand.equalsIgnoreCase("left"))
{
//do some action
}
else if(voiceCommand.equalsIgnoreCase("right"))
{
//do some action
}
}

15. Limitations
 Similar to other assistive technologies, voice
recognition systems have their own
limitations. The most significant limitation is
that they can be inaccurate.
 You always have to make your voice clear
and easy to understand.
 Lastly,
not all persons with motor disabilities
can use voice recognition systems.