title: How does setMicrophoneMute() work?
body: <p>I have been trying to use Android's <code>AudioManager.setMicrophoneMute()</code> without much success. That is, it simply refuses to mute the microphone, no matter what I do. </p>
  
  <p>I searched the web for some clues and I found several references reporting similar experience:</p>
  
  <ul>
  <li><a href="http://groups.google.com/group/android-developers/browse_thread/thread/cf57da02446e424a" rel="noreferrer">AudioManger.setMicrophoneMute functionality not working??</a></li>
  <li><a href="https://stackoverflow.com/questions/5217437/setmicrophonemuteboolean-doesnt-work-on-some-devices">setMicrophoneMute(boolean) doesn't work on some devices</a></li>
  <li><a href="https://stackoverflow.com/questions/3043330/unable-to-mute-the-microphone-in-android">Unable to mute the microphone in Android</a></li>
  </ul>
  
  <p>Which begs the question: Does <code>AudioManager.setMicrophoneMute()</code> work at all? Is it only a stub method, waiting to be implemented in some future version of Android? If not, how does it work? What do I need to make it work? What are the conditions that make it work as its name implies?</p>
  
  <p><strong>EDIT:</strong> I noticed that the documentation for this method says:</p>
  
  <blockquote>
    <p>This method should only be used by applications that <em>replace</em> the
    platform-wide management of audio settings or the main telephony
    application.</p>
  </blockquote>
  
  <p>What does this mean? Why would I want to replace the platform-wide management? Do I really need to do that? If so, how do I do that?</p>
  
  <p><strong>EDIT:</strong> The answer below is great but I still don't understand:</p>
  
  <ol>
  <li>How is that flag (SET_MIC_MUTE in database) being used?</li>
  <li>When does this flag actually disconnect the microphone signal from
  the pre-amplifier circuit inside the phone?</li>
  <li>If it doesn't do that, who does that?</li>
  <li>If nothing does that, how is this "mute" expected to work?</li>
  </ol>
  
  <p>Please explain. Thanks.</p>