How to play audio through built-in earpiece speaker

Question

I have seen some apps like WhatsApp has a feature to play audio clips only through earpiece(phone call speaker) when the user brings up the device near to ear. Otherwise its playing via normal built-in speaker.

I am using MPMoviePlayer for playing audio clips.

I did go through lots of similar questions and answers on the internet, and all the answers say to set the AudioSession Category to PlayAndRecord. Thats it.

I did the same, but couldn't get the exact result that I want to get.

// Audio Player
self.audioSession = [AVAudioSession sharedInstance];
[audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];
[audioSession setActive:YES error:nil];
self.moviePlayer = [[MPMoviePlayerController alloc] init];
self.moviePlayer.view.hidden = YES;

//    AVAudioSessionPortDescription *routePort = self.audioSession.currentRoute.outputs.firstObject;
//    NSString *portType = routePort.portType;
//    
//    if ([portType isEqualToString:@"Receiver"]) {
//        [self.audioSession  overrideOutputAudioPort:AVAudioSessionPortOverrideSpeaker error:nil];
//    } else {
//        [self.audioSession  overrideOutputAudioPort:AVAudioSessionPortOverrideNone error:nil];
//    }

Can anyone please show me how and where can I modify the source to play audio through the earpiece speaker only when the user brings up the device?

Answer 1

I could do it using AVAudioSession and ProximityMonitering

- (void)viewDidLoad {
    [super viewDidLoad];

    [UIDevice currentDevice].proximityMonitoringEnabled = YES;

    if ([UIDevice currentDevice].proximityMonitoringEnabled == YES) {
        [[NSNotificationCenter defaultCenter] addObserver:self
                                               selector:@selector(proximityChanged:)
                                                     name:@"UIDeviceProximityStateDidChangeNotification"
                                               object:[UIDevice currentDevice]];
    }
}


- (void) proximityChanged:(NSNotification *)notification {
    UIDevice *device = [notification object];
    NSLog(@"In proximity: %i", device.proximityState);

    if(device.proximityState == 0){
        [audioSession  overrideOutputAudioPort:AVAudioSessionPortOverrideSpeaker error:nil];
    }
    else{
        [audioSession  overrideOutputAudioPort:AVAudioSessionPortOverrideNone error:nil];
    }
}

Play Audio

audioSession = [AVAudioSession sharedInstance];
[audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];
[audioSession setActive:YES error:nil];

AVAudioSessionPortDescription *routePort = audioSession.currentRoute.outputs.firstObject;
NSString *portType = routePort.portType;

NSLog(@"PortType %@", portType);

if ([portType isEqualToString:@"Receiver"]) {
    [audioSession  overrideOutputAudioPort:AVAudioSessionPortOverrideSpeaker error:nil];
}