Question

I just implemented game center support in my app like it’s described here How To Make A Simple Multiplayer Game with Game Center Tutorial: Part 1/2.

It is realized as a singleton. In my app delegate:

    // At the end of applicationDidFinishLaunching, right before 
    // the last line that calls runWithScene:
    [[GCHelper sharedInstance] authenticateLocalUser];

A little overview over the methods and attributes:

@interface GCHelper : NSObject {
    BOOL gameCenterAvailable;
    BOOL userAuthenticated;
}

@property (assign, readonly) BOOL gameCenterAvailable;

+ (GCHelper *)sharedInstance;
- (void) authenticateLocalUser;

@end

Since there is now reference to the GCHelper in my app delegate I wonder how to actually test in an other class (where I submit score) if game center is available.

How do I get the singleton instance of GCHelper in another class?

Answer 1

Just see how I get the instance of singleton class in another class :

//DataClass.h

@interface DataClass : NSObject {    

int i;   

}    
@property(nonatomic,assign)int i;    
+(DataClass*)getInstance;    
@end  

//DataClass.m

@implementation DataClass    
@synthesize i;    
static DataClass *instance =nil;    
+(DataClass *)getInstance    
{    
@synchronized(self)    
{    
    if(instance==nil)    
{    

    instance= [DataClass new];    
}    
}    
return instance;    
}    

Now in your view controller you need to call this method as :

DataClass *obj=[DataClass getInstance];  
obj.i= // whatever you want;  

This variable will be accessible to every view controller. You just have to create an instance of Data class.