title: Resuming twilio call after audio session interruption
body: <p>I am developing a VoIP app that uses Twilio for telephony. The issue i am facing is that if the  AVAudioSession is interrupted while a call is in progress, for example by an incoming FaceTime call, then i am not able continue using Audio session after the interruption ends. The call does not disconnect , but no sound is audible and the microphone is not recording anything either. </p>
  
  <p>I have registered for the AVAudioSessionInterruptionNotification and in the notification handler, I do the following : </p>
  
  <pre><code> // get the user info dictionary
  NSDictionary *interuptionDict = notification.userInfo;
  // get the AVAudioSessionInterruptionTypeKey enum from the dictionary
  NSInteger interuptionType     = [[interuptionDict valueForKey:AVAudioSessionInterruptionTypeKey] integerValue];
  // decide what to do based on interruption type here...
  switch (interuptionType)
  {
      case AVAudioSessionInterruptionTypeBegan:
  
          DLog(@"Audio Session Interruption case started.");
          [self setAudioSessionActive:NO];
          break;
  
      case AVAudioSessionInterruptionTypeEnded:
      {
          DLog(@"Audio Session Interruption case ended.");
          [self setAudioSessionActive:YES];
          break;
      }
      default:
          DLog(@"Audio Session Interruption Notification case default.");
          break;
  }
  
  // Activate or deactivate the app's audio session
  - (void)setAudioSessionActive:(BOOL)active
  {
  BOOL success = NO;
  NSError *error = nil;
  success = [[AVAudioSession sharedInstance] setActive:active error:&amp;error];
  if (error)
  {
      DLog(@"Error setting audio session : %@", [error description]);
  }
  else if (success)
  {
      DLog(@"Audio session state set successfully :")
  }
  }
  </code></pre>
  
  <p>I do not get any errors but the ongoing call just doesn't work. </p>
  
  <p>I have read the Audio session programming guide , Human interface guidelines for audio  and other audio related apple documentation. I believe I am following the correct steps.
  Please give any suggestions as what I might be missing here. </p>