pass data from view to view and delegates..

[vogueestylee]

hi there, I my program I need to pass MSMutableArrays from one to another viewcontrollers but I', not sure if the "basic scheme" of my program is ok..

I handle all conection voids and xmlparser in main controller.. is it good way?

shouldn't I handle this in AppDelegate.m file? I'm just unsure about if I doing it good (it is working but still..)

and another, for passing data I shouldn't use global variables so I should use delegate.. I make a simple example but it is not working

AppDelegate.h

#import <UIKit/UIKit.h>

@class ViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>{


    NSMutableArray *pole;



}
@property (nonatomic, retain) NSMutableArray *pole;
@property (strong, nonatomic) UIWindow *window;

@property (strong, nonatomic) ViewController *viewController;

@end

AppDelegate.m

@synthesize pole;


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
   
    
    pole = [[NSMutableArray alloc] init];
    
    NSString * f = @"foo";
    NSString * b = @"bar";
    NSString * z = @"baz";
  pole = [NSMutableArray arrayWithObjects:f,b,z,nil];
    for (id obj in pole){
        NSLog(@"%@", obj);
    }
    
    return YES;

}

ViewController.m

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
    
    
    AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    
    NSMutableArray *temp = appDelegate.pole;
   // NSLog(@"%i",temp);
    for (id obj in temp){
        NSLog(@"%@", obj);
    }
}

so.. red ones are my added code.. in AppDelegate.m is code working - NSLOG is giving me the foo bar baz items but in ViewController.m not.. so.. what I didn't understand there..?

[apatsufas]

The problem is you are allocating and adding data to your array after you present the viewController.

Move the red lines in your App Delegate to the top of the didFinishLaunchingWithOption function and it should work.

[Duncan C]

Originally Posted by apatsufas

The problem is you are allocating and adding data to your array after you present the viewController.

Move the red lines in your App Delegate to the top of the didFinishLaunchingWithOption function and it should work.

Although putting globals in your app delegate is not recommended. It's cleaner and better to use a data container singleton. Take a look at the password generator app tutorial linked in my signature. It shows how to create a data container singleton.

[vogueestylee]

apatsufas - thanks!

duncan - thank you I will read this. and back to my question about "basics" of programming..? it is better to do thinks like downloading and so on in appdelegate or it is also correct in viewController.m file? how you, professionals do this?

[AndreaT]

Totally agree with Duncan C. Usually if we want to share an Object trough different view is better and cleaner to have a singleton class managing this.

In a standard app is better if you create more then one singleton to manage different thing. For exmple, audioManager, dataManager and so on and recall this as you need.

Here you can find a code snippet to create a singleton class [Objective C] ARC Compatible Singleton - Pastebin.com

My2cent