Please could anyone help me passing an array from one class to another

[lozjoyk]

Hi, i have a standard tab bar application and i am trying to pass an array from the first view to the second view but really struggling.

here is my FirstViewController.h:

Code: (Objective-C)

#import <UIKit/UIKit.h>

@interface FirstViewController : UIViewController {

    NSArray *theArray;
    
}

@property (nonatomic, retain) NSArray *theArray;

@end

FirstViewController.m:

Code: (Objective-C)

#import "FirstViewController.h"

@implementation FirstViewController
@synthesize theArray;

- (void)viewDidLoad {
    
    [super viewDidLoad];    
    
    theArray = [NSArray arrayWithObjects:@"A",@"B", @"C",nil];
    
    NSLog(@"theArray - %@", theArray);

}
...

its in the second view that i want to retrieve the values of the array.

SecondViewController.h:

Code: (Objective-C)

#import <UIKit/UIKit.h>
#import "FirstViewController.h"

@interface SecondViewController : UIViewController {
    
}

@end

SecondViewController.m:

Code: (Objective-C)

#import "SecondViewController.h"

@implementation SecondViewController


- (void)viewDidLoad {
    
    [super viewDidLoad];
    
    FirstViewController *firstViewArray = [[FirstViewController alloc] init];
    
    NSArray *arrayValues = [firstViewArray theArray];
    
    NSLog(@"second view array - %@", arrayValues);
    
    
}
...

the result i get from NSLog is ...

second view array - (null)

and i cant figure out why it wont pass across.

any help would be greatly appreciated.

[fujilla]

With
FirstViewController *firstViewArray = [[FirstViewController alloc] init]; 
what you are actually saying is create a new instance of FirstViewController called firstViewArray, not actually creating an array called firstViewArray.

What are you wanting to do with the contents of the array?

Nick
http://myfirstiphoneapp.co.uk

[fujilla]

Hopefully one or some of these will help you:

http://www.devx.com/wireless/Article/42476/1954
http://forums.pragprog.com/forums/83/topics/3604
http://gregorykaiser.wordpress.com/2009/05/13/385/
http://forums.bignerdranch.com/viewtopic.php?f=87&t=2828
http://forums.bignerdranch.com/viewtopic.php?f=49&t=487
http://www.iphonedevsdk.com/forum/iphone-sdk-development/54859-sharing-data-between-view-controllers-other-objects.html
http://stackoverflow.com/questions/5210535/passing-data-between-view-controllers

Nick
http://myfirstiphoneapp.co.uk/

[lozjoyk]

Hi, thanks for the reply.

I got round it by setting the arrays to global, is this a bad way? i only want to make reference to the array in other views.

Cheers.

[fujilla]

I guess if it is a global/constant which will never change, then it is probably OK.

Nick

[fujilla]

Here is a link to my latest blog post, as the subject of passing data between view controllers is something I had initially struggled to do with my first app:

http://myfirstiphoneapp.co.uk/2011/09/passing-data-between-view-controllers-using-a-singleton-class/