Bluetooth audio session set up

bluetooth-audio.m

// App delegate

#import <AVFoundation/AVFoundation.h>// place in .h

// applicationDidFinishLaunchingWithOptions
// [self prepareAudioSession]; 

- (BOOL)prepareAudioSession {

     // deactivate session
     BOOL success = [[AVAudioSession sharedInstance] setActive:NO error: nil];
     if (!success) {
         NSLog(@"deactivationError");
     }

     // set audio session category AVAudioSessionCategoryPlayAndRecord options AVAudioSessionCategoryOptionAllowBluetooth
     success = [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord withOptions:AVAudioSessionCategoryOptionAllowBluetooth error:nil];
     if (!success) {
         NSLog(@"setCategoryError");
     }

     // activate audio session
     success = [[AVAudioSession sharedInstance] setActive:YES error: nil];
     if (!success) {
         NSLog(@"activationError");
     }
  return success;
}

// ViewController

- (id)init 
{
  self = [super init];
  
  if (self) {
    [[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(myInterruptionSelector:)
                                             name:AVAudioSessionInterruptionNotification
                                           object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(myRouteChangeSelector:)
                                                 name:AVAudioSessionRouteChangeNotification
                                              object:nil];
  }
  return self;
}

- (void)listAvailableInputs
{
  // portDesc.portType could be for example - BluetoothHFP, MicrophoneBuiltIn, MicrophoneWired
  NSArray *availInputs = [[AVAudioSession sharedInstance] availableInputs];
  int count = [availInputs count];
  for (int k = 0; k < count; k++) {
    AVAudioSessionPortDescription *portDesc = [availInputs objectAtIndex:k];
    NSLog(@"input%i port type %@", k+1, portDesc.portType);
    NSLog(@"input%i port name %@", k+1, portDesc.portName);
  }
}

- (void)myRouteChangeSelector:(NSNotification*)notification
{
      AVAudioSessionRouteDescription *currentRoute = [[AVAudioSession sharedInstance] currentRoute];
      NSArray *inputsForRoute = currentRoute.inputs;
      NSArray *outputsForRoute = currentRoute.outputs;
      AVAudioSessionPortDescription *outPortDesc = [outputsForRoute objectAtIndex:0];
      NSLog(@"current outport type %@", outPortDesc.portType);
      AVAudioSessionPortDescription *inPortDesc = [inputsForRoute objectAtIndex:0];
      NSLog(@"current inPort type %@", inPortDesc.portType);
}