android voice recognition

If you are willing to develop a voice recognition system in the android phone, you will follow these steps:

create an activity.
create a button which launch the voice activity.
first you will get the package manager to find that the device has the ability to perform voice recognition.
PackageManager pm = getPackageManager();
Get the list from the package manager as:
List activities = pm.queryIntentActivities(new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0);
check its size
activities.size() if it is greater than the zero then go for further processing.

Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
        intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
                RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
        intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "Speech recognition demo");
        startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);

this will launch the voice recognition activity and return a result.
Override this method

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == VOICE_RECOGNITION_REQUEST_CODE && resultCode == RESULT_OK) {
            // Fill the list view with the strings the recognizer thought it could have heard
            ArrayList matches = data.getStringArrayListExtra(
                    RecognizerIntent.EXTRA_RESULTS);
            mList.setAdapter(new ArrayAdapter(this, android.R.layout.simple_list_item_1,
                    matches));
        }

        super.onActivityResult(requestCode, resultCode, data);
    }

Full code of the application can be:

public class Main extends Activity implements OnClickListener{
   
    private static final int VOICE_RECOGNITION_REQUEST_CODE = 1234;
   
    private ListView mList;
   
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    
        Button speakButton = (Button) findViewById(R.id.btn_speak);
        mList = (ListView) findViewById(android.R.id.list);
       
        PackageManager pm = getPackageManager();
        List activities = pm.queryIntentActivities(
                new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0);
        if (activities.size() != 0) {
            speakButton.setOnClickListener(this);
        } else {
            speakButton.setEnabled(false);
            speakButton.setText("Recognizer not present");
        }
    }
   
    public void onClick(View v) {
        if (v.getId() == R.id.btn_speak) {
            startVoiceRecognitionActivity();
        }
    }
   
  
    private void startVoiceRecognitionActivity() {
        Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
        intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
                RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
        intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "Speech recognition demo");
        startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);
    }
   
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == VOICE_RECOGNITION_REQUEST_CODE && resultCode == RESULT_OK) {
            // Fill the list view with the strings the recognizer thought it could have heard
            ArrayList matches = data.getStringArrayListExtra(
                    RecognizerIntent.EXTRA_RESULTS);
            mList.setAdapter(new ArrayAdapter(this, android.R.layout.simple_list_item_1,
                    matches));
        }

        super.onActivityResult(requestCode, resultCode, data);
    }
}

Please comment if you have any problem in this code.

Event Handling in Android

There are many events in android which can be handle through code but I am currently go with onClickListener.
As you know that all events are listen through a listener and we will work with OnClickListener.
You have a button in xml layout and you are accessing it with the code:
       Button myBtn = (Button) findViewById(R.id.my_button);
Now we are register a listener with it as
        myBtn.setOnClickListener(new MyListener ());//Object_of_OnClickListener_class

Now I am going to develop a class which will be implement OnClickListener which is member of android.view.View.OnClickListener.

Import android.view.View.OnClickListener;

public class MyListener implements OnClickListener{
   public void onClick(View v) {
         //your action
   }
}

Now write your logic for your action.

Practice it and let me know if you have any problem.