How to access array from different class in objective c

Question

I know that this question has been asked several times already, but after extensive search, none of them work for me so far. I want to avoid using a singleton if possible. Sorry if this is considered a repeat question.

I have a MutableArray with 5 objects in my ViewController.m file called storyList. I want to be able to access this storyList array in my DetailViewController.m file.

One method I have tried is: (storyListArrayinDetail is a new array in detailviewcontroller, storyList is the array with 5 objects from ViewController.h) In ViewController.h

DetailViewController *controller;

In ViewController.m

 controller = [[DetailViewController alloc]init];
 controller.storyListArrayinDetail = [[NSMutableArray alloc]init];       
 controller.storyListArrayinDetail = storyList;

When I log controller.storyListArrayinDetail in ViewController.m, I get the correct array of 5 objects. However, when I log storyListArrayinDetail in DetailViewController.m, I get nothing.

Because you have allocated a new, completely separated DetailViewController that has nothing to do with the one that adds the 5 items to the array. — Ramy Al Zuhouri, Apr 03 '13 at 22:42
[Check this out](http://en.wikipedia.org/wiki/Instance_(computer_science)) — RileyE, Apr 03 '13 at 22:45
I need additional information: how to you instantiate the DetailViewController and ViewController? Do you have a pointer to them in your app delegate? — Ramy Al Zuhouri, Apr 03 '13 at 22:47
Are you using a segue to trigger the loading of the `DetailViewController`? — rob mayoff, Apr 03 '13 at 23:13
@robmayoff I am loading a tableView and then segue for loading a DetailViewController — Spenciefy, Apr 03 '13 at 23:28

score 0 · Answer 1 · answered Apr 03 '13 at 22:49

0

Try overriding the method (id)init on DetailViewController.m ,and initialize storyListArrayinDetail here. Then, whenever initializing a DetailViewController you will be initializing storyListArrayinDetail as well. So, for sending your storyList just use your code as this:

controller = [[DetailViewController alloc]init];
controller.storyListArrayinDetail = storyList;

Hope that helps

answered Apr 03 '13 at 22:49

CoderPug

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9
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How do I use the array `controller.storyListArrayinDetail` in DetailViewController? There is no controller defined in detailViewController – Spenciefy Apr 03 '13 at 23:17
This is what I meant, on `DetailViewController.m` override init method and initialize `storyListArrayinDetail` like this: `- (id)init { self = [super init]; if (self) { storyListArrayinDetail = [[NSMutableArray alloc]init]; } return self; }` No need to use `controller`, because you are inside `DetailViewController` class. – CoderPug Apr 04 '13 at 16:17

random · Answer 2 · 2013-04-04T02:20:07.460

You can create a new init method in your DetailViewController and pass in the array when you initialize it.

//Assuming DetailViewController is in fact a UIViewController, not sure from init method in OP.

DetailedViewController.h

@interface DetailedViewController : UIViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil withDataArray:(NSArray*)dataArray;
@end

DetailedViewController.m

@interface DetailedViewController () {
   NSArray *myDataArray;
}

@end

@implementation DetailedViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil withDataArray:(NSArray*)dataArray
    {
        self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
        if (self) {
            // Custom initialization
            myDataArray = [NSArray arrayWithArray:dataArray];
        }
        return self;
    }

...

Then in DetailedViewController you can use myDataArray. Hope that helps.

EDIT: To include Hot_Licks suggestion:

DetailedViewController.h

@interface DetailedViewController : UIViewController
@property(nonatomic, assign)NSArray *myDataArray;
@end

ViewController.m

DetailedViewController *controller = [[DetailViewController alloc]init];
[controller setMyDataArray:xyArray];

Or you can add a property to the controller and set it with the array address after the controller is created. — Hot Licks, Apr 04 '13 at 02:16
Thanks for the answer, and I think it should work, but when I put `- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil withDataArray:(NSArray*)dataArray;` in `DetailViewController.h`, I get 2 errors: `Expected member name or '; ' after declaration specifiers` and `Type name requires a specifier or qualifier` — Spenciefy, Apr 04 '13 at 05:50
Is you DetailViewController a UIViewController? Or a UIView? — random, Apr 04 '13 at 23:19

How to access array from different class in objective c

2 Answers2