viewcontroller001.m

@interface ViewController ()
<OTSessionDelegate, OTSubscriberKitDelegate, OTPublisherDelegate>
@end

viewcontroller002.m

//
//  ViewController.m
//  OpentokRTC

// ...
#import <OpenTok/OpenTok.h>
// ...


@interface ViewController ()
<OTSessionDelegate, OTSubscriberKitDelegate, OTPublisherDelegate>
@end

@implementation ViewController {
    OTSession* _session;
    OTPublisher* _publisher;
    OTSubscriber* _subscriber;
    id<OTVideoCapture> _cameraCapture;
// ...

viewcontroller003.m

- (void)sessionDidConnect:(OTSession*)session
{
    NSLog(@"sessionDidConnect (%@)", session.sessionId);
    
    //Change the text of the status label
    StatusLabel.text = [self getSessionStatus];
    
    //Change the status label color
    [self changeStatusLabelColor];
    
    
    // Step 2: We have successfully connected, now instantiate a publisher and
    // begin pushing A/V streams into OpenTok.
    
    
    [self doPublish];
}

- (void)sessionDidDisconnect:(OTSession*)session
{
    NSString* alertMessage =
    [NSString stringWithFormat:@"Session disconnected: (%@)",
     session.sessionId];
    NSLog(@"sessionDidDisconnect (%@)", alertMessage);
    
    //TalkingWithLabel.text = @"";
    
    //Change the text of the status label
    StatusLabel.text = [self getSessionStatus];
    
    //Change the status label color
    [self changeStatusLabelColor];
    
    //Clean all the subscribers
    [self cleanupSubscriber];
}