Question

i have fbid a instance variable in my app delegate i want to use it in every class in my whole application without using NSUSERDEFAULT .i want to use extern data type but i am not getting any thing how to declare extern variable and how to use please help ?

Answer 1

You can declare property variable in your Application Delegate.

Than you can access that variable anywhere as

//To set value
AppDelegate *yourAppdelegate = (AppDelegate *)[[UIApplication] sharedApplication]delegate];
yourAppdelegate.yourStringVariable = @"";

//To get value 
AppDelegate *yourAppdelegate = (AppDelegate *)[[UIApplication] sharedApplication]delegate];
NSString *accessValue = yourAppdelegate.yourStringVariable;

EDIT

Let’s say you have MyViewController

//Header file

@interface MyViewController : UIViewController
{
     NSString *classLevelProperty;
}

@property (nonatomic, retain) NSString *classLevelProperty;

@end    

//Implementation file

@implementation MyViewController

@synthesize classLevelProperty;

-(void)viewDidLoad
{
    AppDelegate *yourAppdelegate = (AppDelegate *)[[UIApplication] sharedApplication]delegate];
    classLevelProperty = yourAppdelegate.yourStringVariable;

     //Here above classLevelProperty is available through out the class. 
}
@end

This can be done in any view controller and that property value of yourStringVariable is available to any viewcontroller or any other class as above code.

Hope this clears. Leave comment if still not able to get it correctly.