Question

I’m new to objective-c and I searched and read several posts here on how to create “global variable” but I just can’t get it to work right, so far I can create it and check it but the values are not persisting on another views, my global var is an array of a custom object called “profile”, I would like to be able to read and write that array from any view of my iphone app (tabbarapplication delegate);

Helper.h

@interface Helper : NSObject {
    int globalInteger;
    NSMutableArray *profiles;
}

@property (nonatomic, retain) NSMutableArray *profiles;

// message from which our instance is obtained
+ (Helper *)sharedInstance;

Helper.m

#import "Helper.h"


@implementation Helper

@synthesize profiles, globalInteger;

+ (Helper *)sharedInstance
{
    // the instance of this class is stored here
    static Helper *myInstance = nil;

    // check to see if an instance already exists
    if (nil == myInstance) {
        myInstance  = [[[self class] alloc] init];
        // initialize variables here
    }
    // return the instance of this class
    return myInstance;
}

ACertainViewController.m

//Initialize Policies Array
NSMutableArray *profs = [[Helper instance] profiles];
profs = [[NSMutableArray alloc] init];

//Sample Data
Profile *prof1 = [[Profile alloc] init];
prof1.name = @"John";

//add
[profs addObject:prof1];
[[[Helper instance] profiles] addObject:prof1];

---

After this point if I check the global var “profiles” contents again it returns count == 0;
As of the globalInteger var I don’t even know how to set its value to be able to read somewhere else in the app.
Any help is much appreciated!
Thanks!!!

Answer 1

Declare your NSMutableArray in your AppDelegate (i.e. MyAppDelegate) class. Then from another class (like your view controller), you can do this:

#import "MyAppDelegate.h"

MyAppDelegate *aDelegate = (MyAppDelegate *)[UIApplication sharedApplication].delegate;
aDelegate.profiles = .... // or do whatever you need to do with the profiles property. 

hope that helps.