title: tts Service explanation in android
body: <p>I have questions regarding the implementation of tts service for android.
  Here's the deal:</p>
  
  <p>-I've looked over Flite code and I see that service is require to have these 3 activities:</p>
  
  <pre><code>&lt;activity
          android:name=".DownloadVoiceData"
          android:label="@string/flite_voice_manager"
          android:theme="@android:style/Theme.Holo" 
          android:configChanges="orientation"&gt;
          &lt;intent-filter&gt;
              &lt;action android:name="android.speech.tts.engine.INSTALL_TTS_DATA" /&gt;
              &lt;category android:name="android.intent.category.DEFAULT" /&gt;
          &lt;/intent-filter&gt;
      &lt;/activity&gt;
      &lt;activity
          android:name=".CheckVoiceData"
          android:label="@string/app_name"
          android:theme="@android:style/Theme.Translucent.NoTitleBar" &gt;
          &lt;intent-filter&gt;
              &lt;action android:name="android.speech.tts.engine.CHECK_TTS_DATA" /&gt;
  
              &lt;category android:name="android.intent.category.DEFAULT" /&gt;
          &lt;/intent-filter&gt;
      &lt;/activity&gt;
      &lt;activity
          android:name=".GetSampleText"
          android:label="@string/app_name"
          android:theme="@android:style/Theme.Translucent.NoTitleBar" &gt;
          &lt;intent-filter&gt;
              &lt;action android:name="android.speech.tts.engine.GET_SAMPLE_TEXT" /&gt;
  
              &lt;category android:name="android.intent.category.DEFAULT" /&gt;
          &lt;/intent-filter&gt;
      &lt;/activity&gt;
  </code></pre>
  
  <p>The actual actions of these activities are self explainable, but I want to know:
  Are they mandatory, how they work ....  I have google it but with no luck.</p>
  
  <ol>
  <li><p>Can anybody point out to some documentation where these activities are explained? </p></li>
  <li><p>Also, is there any documentation of tts service flow explained in detail?</p></li>
  </ol>
  
  <p>Thanx in advance.</p>