CODEWITHSUNDEEP
iosobjective-c
Brittany
Brittany

Reputation: 1439

Singleton Created, Errors upon use in ViewController?

I've defined NSUbiquitousKeyValueStore as 'CloudStore' in one ViewController (PointsViewController.m), and created a CloudStore singleton in order to be able to use it in another ViewController (PayViewController.m).

However, when I call the Singleton in PayViewController.m, it then throws an error on every NSString reference under it. The error reads: "No known class method forStringForKey" and "No known method for setString:forKey". Am I missing something here? Have I implemented the singleton incorrectly? See ViewController & Singleton code below.

PointsViewController.m

 NSUbiquitousKeyValueStore *CloudStore = [NSUbiquitousKeyValueStore defaultStore];

               NSString *pointsStr = [CloudStore stringForKey:@"UserWantsToBuyPoints"];
               [CloudStore setString:pointsStr forKey:@"UserWantsToBuyPoints"];
               [CloudStore synchronize];


                NSString *TotalUserPoints = [CloudStore stringForKey:@"TotalUserPoints"];


                int pointsInt = [pointsStr intValue];
                int TotalUserPointsInt = [TotalUserPoints intValue];


                TotalUserPointsInt = TotalUserPointsInt + pointsInt;

                NSString *totalStr = [NSString stringWithFormat:@"%d", TotalUserPointsInt];

                [CloudStore setObject:totalStr forKey:@"TotalUserPoints"];
                [CloudStore synchronize];

PayViewController.m

[CloudStore singleton];

        NSString *pointsStr = [CloudStore stringForKey:@"UserWantsToBuyPoints"];
        [CloudStore setString:pointsStr forKey:@"UserWantsToBuyPoints"];
        [cloudStore synchronize];


        NSString *TotalUserPoints = [CloudStore stringForKey:@"TotalUserPoints"];


        int pointsInt = [pointsStr intValue];
        int TotalUserPointsInt = [TotalUserPoints intValue];


        TotalUserPointsInt = TotalUserPointsInt + pointsInt;

        NSString *totalStr = [NSString stringWithFormat:@"%d", TotalUserPointsInt];

        [CloudStore setObject:totalStr forKey:@"TotalUserPoints"];
        [CloudStore synchronize];
       NSString *pointsStr = [CloudStore stringForKey:@"UserWantsToBuyPoints"];
       [CloudStore setString:pointsStr forKey:@"UserWantsToBuyPoints"];
       [CloudStore synchronize];


        NSString *TotalUserPoints = [CloudStore stringForKey:@"TotalUserPoints"];


        int pointsInt = [pointsStr intValue];
        int TotalUserPointsInt = [TotalUserPoints intValue];


        TotalUserPointsInt = TotalUserPointsInt + pointsInt;

        NSString *totalStr = [NSString stringWithFormat:@"%d", TotalUserPointsInt];

        [CloudStore setObject:totalStr forKey:@"TotalUserPoints"];
        [CloudStore synchronize];

CloudStore.h (singleton)

#import <Foundation/Foundation.h>

@interface CloudStore : NSObject

+(CloudStore *)singleton;

@end

CloudStore.m (singleton)

#import "CloudStore.h"

@implementation CloudStore

+(CloudStore *)singleton {
    static dispatch_once_t pred;
    static CloudStore *shared = nil;
    dispatch_once(&pred, ^{
        shared = [[CloudStore alloc] init];
    });
    return shared;
}

@end

Upvotes: 0

Views: 46

Answers (1)

Midhun MP
Midhun MP

Reputation: 107131

You are actually messing up the singleton and iCloud storage objects in your code. You need to declare and initialise the iCloud object in your singleton and use it:

CloudStore.h

#import <Foundation/Foundation.h>

@interface CloudStore : NSObject

// Storage property
@property (nonatomic, strong) NSUbiquitousKeyValueStore *cloud;

+ (CloudStore *)sharedStorage;

@end

CloudStore.m

#import "CloudStore.h"

@implementation CloudStore

+ (CloudStore *)sharedStorage
{
    static dispatch_once_t pred;
    static CloudStore *shared = nil;
    dispatch_once(&pred, ^{
        shared = [[CloudStore alloc] init];
        [shared initStorage];
    });
    return shared;
}

- (void)initStorage
{
   cloud = [NSUbiquitousKeyValueStore defaultStore];
}
@end

And wherever you want to use the CloudStore variable use it like:

Setting data:

[[[CloudStore sharedStorage] cloud] setObject:totalStr forKey:@"TotalUserPoints"];

Getting data:

 NSString *pointsStr = [[[CloudStore sharedStorage] cloud] stringForKey:@"UserWantsToBuyPoints"];

Synchronising:

[[[CloudStore sharedStorage] cloud] synchronize];

You should read this nice tutorial : iOS Design Patterns, it'll help you to understand the usage of singleton much better.

Upvotes: 1

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