Sunday, 25 August 2013

Would someone please straighten me out with this Android voice recognition class?

Would someone please straighten me out with this Android voice recognition
class?

I'm analyzing this Voice Recognizer class and need help understanding this
line in the code. What is the role of the following line? Does it create a
list of all of the activities on the android platform loaded on the
device? I especially find the resolve info bit confusing...
List activities = pm.queryIntentActivities(new Intent(
Here is the code used in context
package com.example.voicerecognitionactivity;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.app.SearchManager;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.os.Bundle;
import android.speech.RecognizerIntent;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Spinner;
import android.widget.Toast;
public class VoiceRecognitionActivity extends Activity {
private static final int VOICE_RECOGNITION_REQUEST_CODE = 1001;
private EditText metTextHint;
private ListView mlvTextMatches;
private Spinner msTextMatches;
private Button mbtSpeak;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
metTextHint = (EditText) findViewById(R.id.etTextHint);
mlvTextMatches = (ListView) findViewById(R.id.lvTextMatches);
msTextMatches = (Spinner) findViewById(R.id.sNoOfMatches);
mbtSpeak = (Button) findViewById(R.id.btSpeak);
}
public void checkVoiceRecognition() {
// Check if voice recognition is present
PackageManager pm = getPackageManager();
List<ResolveInfo> activities = pm.queryIntentActivities(new Intent(
RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0);
if (activities.size() == 0) {
mbtSpeak.setEnabled(false);
Toast.makeText(this, "Voice recognizer not present",
Toast.LENGTH_SHORT).show();
}
}
public void speak(View view) {
Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
// Specify the calling package to identify your application
intent.putExtra(RecognizerIntent.EXTRA_CALLING_PACKAGE, getClass()
.getPackage().getName());
// Display an hint to the user about what he should say.
intent.putExtra(RecognizerIntent.EXTRA_PROMPT, metTextHint.getText()
.toString());
// Given an hint to the recognizer about what the user is going to
say
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
RecognizerIntent.LANGUAGE_MODEL_WEB_SEARCH);
// If number of Matches is not selected then return show toast
message
if (msTextMatches.getSelectedItemPosition() ==
AdapterView.INVALID_POSITION) {
Toast.makeText(this, "Please select No. of Matches from spinner",
Toast.LENGTH_SHORT).show();
return;
}
int noOfMatches = Integer.parseInt(msTextMatches.getSelectedItem()
.toString());
// Specify how many results you want to receive. The results will be
// sorted where the first result is the one with higher confidence.
intent.putExtra(RecognizerIntent.EXTRA_MAX_RESULTS, noOfMatches);
startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);
}
@Override
protected void onActivityResult(int requestCode, int resultCode,
Intent data) {
if (requestCode == VOICE_RECOGNITION_REQUEST_CODE)
//If Voice recognition is successful then it returns RESULT_OK
if(resultCode == RESULT_OK) {
ArrayList<String> textMatchList = data
.getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);
if (!textMatchList.isEmpty()) {
// If first Match contains the 'search' word
// Then start web search.
if (textMatchList.get(0).contains("search")) {
String searchQuery =
textMatchList.get(0).replace("search",
" ");
Intent search = new Intent(Intent.ACTION_WEB_SEARCH);
search.putExtra(SearchManager.QUERY, searchQuery);
startActivity(search);
} else {
// populate the Matches
mlvTextMatches
.setAdapter(new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,
textMatchList));
}
}
//Result code for various error.
}else if(resultCode == RecognizerIntent.RESULT_AUDIO_ERROR){
showToastMessage("Audio Error");
}else if(resultCode == RecognizerIntent.RESULT_CLIENT_ERROR){
showToastMessage("Client Error");
}else if(resultCode == RecognizerIntent.RESULT_NETWORK_ERROR){
showToastMessage("Network Error");
}else if(resultCode == RecognizerIntent.RESULT_NO_MATCH){
showToastMessage("No Match");
}else if(resultCode == RecognizerIntent.RESULT_SERVER_ERROR){
showToastMessage("Server Error");
}
super.onActivityResult(requestCode, resultCode, data);
}
void showToastMessage(String message){
Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}
}

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