Question

Below is the code in my singleton to add a string to an array. The first NSLog returns the correct string but the second NSLog does not and returns null. If there is any relevant code I need to add let me know. Thanks.

 +(void) addArray:(NSString *)string
{
    NSLog(@"%@",string);

    Singleton *shared = [Singleton sharedManager];
    [shared.array addObject:string];

    NSLog(@"array: %@", shared.array);
}

I added this code to my singleton.m

- (id)init
{
    self = [super init];

    if (self) {
        // Work your initialising magic here as you normally would
        array = [[NSMutableArray alloc]init];
    }

    return self;
}

In another part of my program I run this code and it prints out the correct information

+(void) setPoints:(int) points
{
    Singleton *shared = [Singleton sharedManager];
    shared.points = points;
    NSLog(@"%d",shared.points);
}

Here is my Singleton method

+ (Singleton *)sharedManager
{
    static Singleton *sharedInstance = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sharedInstance = [[Singleton alloc] init];
        // Do any other initialisation stuff here
        array = [[NSMutableArray alloc]init];
    });
    return sharedInstance;
}

Answer 1

It’s possible that you forgot to alloc-init array in your Singleton init.