// MyGameUpResponder.h
#import <Foundation/Foundation.h>
#import <GUResponderProtocol.h>

@interface MyGameUpResponder : NSObject <GUResponderProtocol>
@end

// MyGameUpResponder.m
#import "MyGameUpResponder.h"

@implementation MyGameUpResponder
- (void)failedPing:(NSInteger)statusCode withError:(NSError*) error
{
    // this is invoked when the ping fails to validate
        // either the ApiKey is invalid
        // or the Gamer Token is invalid
        // or the GameUp service is unreachable
}
- (void)retrievedGameData:(GUGame*)game
{
    // this is called whenever some game data is received.
}
// other methods that the protocol requires ...
@end

// MyGameHelper.h
#import <GUGameUp.h>

@interface MyGameHelper : NSObject
@property(readonly) GUGameUp* gameup;
// ... other properties etc
@end

// MyGameHelper.m
#import "MyGameUpResponder.h"

static NSString *const MYGAME_API_KEY = @"your-api-key";

- (id)init {
    self = [super init];
    if (self) {
        // ... other init procedures you'd like to do!

        MyGameUpResponder *responder = [[MyGameUpResponder alloc] init];
        _gameup = [[GUGameUp alloc] initWithApiKey:MYGAME_API_KEY withResponder:responder];
    }
}
// other methods ...

// MyGameHelper.m

// let's imagine that this is the method invoked when the gamer taps on 'Sign in' in your game.
- (void)onLoginClick 
{
    // Get or create a unique device ID
    UIDevice *device = [UIDevice currentDevice];
    NSString  *currentDeviceId = [[device identifierForVendor]UUIDString];
    // if you'd like to log the gamer in seamlessly...
    [_gameup loginAnonymouslyWith:currentDeviceId];

    // or if you'd like the gamer to login through Twitter using a webView:
    UIViewController* webViewController = [_gameup loginThroughBrowserToTwitter];
}
// other methods ...

// MyGameUpResponder.m

// ... other methods ...

- (void)successfullyLoggedinWithSession:(id)session 
{
    // Called with the new session when login completes successfully.
    // You may want to:
    //  * Store it - most other gamer-specific method requires this session!
    //  * Permanently Store it and retrieve it when your game restarts using [session getGamerToken];
    //  * Update your game's state.
    //  * Welcome the user!
}
- (void)failedToLoginWithError:(NSError*) error
{
    // Called when some sort of error has occured...
}
- (void)loginCancelled
{
    // Called when the gamer has tapped on the 'Cancel' button...
}

// ... other methods ...

- (void)application:(UIApplication *)application didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)token
{
    GUSession* session = ...;
    [session subscribePushWithDeviceToken:token];
}