title: synthesizeToFile failed: not bound to TTS engine , when using TextToSpeech in android
body: <p>I am using <code>Android TextToSpeech API</code>, I want to save the convert text2speech as a file on the SD-card memory, but I got the error: </p>
  
  <pre><code> synthesizeToFile failed: not bound to TTS engine
  </code></pre>
  
  <p>My code to use TTS is :</p>
  
  <pre><code>public void onActivityResult(int requestCode, int resultCode, Intent intent) {
  
  
          if (requestCode == MY_DATA_CHECK_CODE) {
              if (resultCode == TextToSpeech.Engine.CHECK_VOICE_DATA_PASS) {
                  tts = new TextToSpeech(this, this);
  
                  if(getIntent() != null){
                      if(getIntent().getExtras()!=null){
                          String d = getIntent().getExtras().getString("data");
  
                          String data[] = d.split("-");
                          bookName = data[0];
                          loadPage(data[0], Integer.parseInt(data[1]));
                      }
                  }
                  Log.d("TTS","Data is loaded");
  
              }
              else {
                  Intent installTTSIntent = new Intent();
                  installTTSIntent.setAction(TextToSpeech.Engine.ACTION_INSTALL_TTS_DATA);
                  startActivity(installTTSIntent);
              }
          }
      }
  </code></pre>
  
  <p>where inside the <code>loadPage()</code> function a call the <code>synthesizeToFile</code> function as below :</p>
  
  <pre><code>String tempDestFile = appTmpPath.getAbsolutePath() +"/"+ fileName;
  tts.synthesizeToFile(speakTextTxt, myHashRender, tempDestFile);
  </code></pre>