CODEWITHSUNDEEP
iphoneiosobjective-cvariablessingleton
Not My Name Car
Not My Name Car

Reputation: 59

Accessing changeable values in a singleton?

First off, I come from Lua, don't blame me for being global variable minded lol. So, I've been reading up on how to use this whole "Singleton system" and I'm not sure if I'm completely missing the point or if I'm just implementing it incorrectly?

The goal of my code is to create a way for multiple files to access a variable that holds the size of an array in a specific file. Here is my singleton:

.h

#import <Foundation/Foundation.h>

@interface GlobalVariables : NSObject
{
    NSNumber *currentGameArrayCount;
    BOOL *isGamePaused;
}

@property (nonatomic, readwrite) NSNumber *currentGameArrayCount;
@property (nonatomic, readwrite) BOOL *isGamePaused;

+ (GlobalVariables *)sharedInstance;


@end

.m

#import "GlobalVariables.h"

@implementation GlobalVariables
@synthesize currentGameArrayCount, isGamePaused;

static GlobalVariables *gVariable;

+ (GlobalVariables *)sharedInstance
{


    if (gVariable == nil) {
        gVariable = [[super allocWithZone:NULL] init];
    }

    return gVariable;
}

- (id)init
{
    self = [super init];
    if (self)
    {
        currentGameArrayCount = [[NSNumber alloc] initWithInt:0];
        isGamePaused = NO;

    }

    return self;
}

@end

and in another file with the array I use:

GlobalVariables *sharedData = [GlobalVariables sharedInstance];
        NSNumber *tmpArrayCount = [sharedData currentGameArrayCount];

        NSInteger tmpCount = [whereStuffActuallyHappens.subviews count]; // Subviews is the array
        NSNumber *currentCount = [NSNumber numberWithInteger:tmpCount];


        tmpArrayCount = currentCount;

the hope of this code was to get the variable in the singeton (currentGameArrayCount) and set it too what the current array count was (currentCount). Am I incorrectly interpreting the purpose of a singleton? Am I just bad at singletons and didn't set it up correctly? Does anyone know how I could achieve the result of getting my array count to be accesible to all my files?

Upvotes: 0

Views: 151

Answers (1)

rmaddy
rmaddy

Reputation: 318854

You have a few issues. Try these changes:

GlobalVariables.h:

#import <Foundation/Foundation.h>

@interface GlobalVariables : NSObject

@property (nonatomic, assign) int currentGameArrayCount;
@property (nonatomic, assign) BOOL gamePaused;

+ (GlobalVariables *)sharedInstance;

@end

GlobalVariables.m:

#import "GlobalVariables.h"

static GlobalVariables *gVariable = nil;

@implementation GlobalVariables

+ (GlobalVariables *)sharedInstance {
    if (gVariable == nil) {
        gVariable = [[self alloc] init];
    }

    return gVariable;
}

- (id)init {
    self = [super init];
    if (self) {
        self.currentGameArrayCount = 0;
        self.gamePaused = NO;
    }

    return self;
}

@end

Now in your other code you can do:

GlobalVariables *sharedData = [GlobalVariables sharedInstance];
int tmpArrayCount = sharedData.currentGameArrayCount;

NSInteger tmpCount = [whereStuffActuallyHappens.subviews count]; // Subviews is the array
sharedData.currentGameArrayCount = tmpCount;

Upvotes: 1

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