title: How to detect if there is a sound in android?
body: <p>I am new to android development. Ive to make an application which detects sound and plays music. I have already taken care of music playing part but the problem is that I don't understand how to put a condition to check that whether there is even a sound or not 
  Im using eclipse and android API 20 and voice recognition intent. Kindly look at the following code.</p>
  
  <pre><code>import android.app.Activity;
  import android.os.Bundle;
  import android.content.Intent;
  import android.content.pm.PackageManager;
  import android.content.pm.ResolveInfo;
  import android.speech.RecognizerIntent;
  import android.view.View;
  import android.widget.ArrayAdapter;
  import android.widget.Button;
  import android.widget.ListView;
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * A very simple application to handle Voice Recognition intents
   * and display the results
   */
  public class MainActivity extends Activity
  {
  
      private static final int REQUEST_CODE = 1234;
      private ListView wordsList;
  
      /**
       * Called with the activity is first created.
       */
      @Override
      public void onCreate(Bundle savedInstanceState)
      {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.voice_recog);
  
          Button speakButton = (Button) findViewById(R.id.speakButton);
  
          wordsList = (ListView) findViewById(R.id.list);
  
          // Disable button if no recognition service is present
          PackageManager pm = getPackageManager();
          List&lt;ResolveInfo&gt; activities = pm.queryIntentActivities(
                  new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0);
          if (activities.size() == 0)
          {
              speakButton.setEnabled(false);
              speakButton.setText("Recognizer not present");
          }
          else
          {startVoiceRecognitionActivity();}
      }
  
      /**
       * Handle the action of the button being clicked
       */
  
  
  
  
      /**
       * Fire an intent to start the voice recognition activity.
       */
      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, "Voice recognition Demo...");
          startActivityForResult(intent, REQUEST_CODE);
      }
  
      /**
       * Handle the results from the voice recognition activity.
       */
      @Override
      protected void onActivityResult(int requestCode, int resultCode, Intent data)
      {
          if (requestCode == REQUEST_CODE &amp;&amp; resultCode == RESULT_OK)
          {
              // Populate the wordsList with the String values the recognition engine thought it heard
              ArrayList&lt;String&gt; matches = data.getStringArrayListExtra(
                      RecognizerIntent.EXTRA_RESULTS);
              wordsList.setAdapter(new ArrayAdapter&lt;String&gt;(this, android.R.layout.simple_list_item_1,
                      matches));
          }
          super.onActivityResult(requestCode, resultCode, data);
      }
  }
  </code></pre>