Question

Sorry for the simple question.
When I see a definition of a property inside the h file, but outside of the class @interface scope, what does it mean ?

@property (nonatomic, readonly) RMMapContents *mapContents;

Here is the code:

@class RootViewController;
@class RMMapContents;

@interface MapTestbedAppDelegate : NSObject <UIApplicationDelegate> {
    UIWindow *window;

    //MAIN VIEW
    //==============

    RootViewController *rootViewController;


    // NETWORK DATA
    // =============

    NSMutableArray  *photoTitles;         // Titles of images
    NSMutableArray  *photoSmallImageData; // Image data (thumbnail)
    NSMutableArray  *photoURLsLargeImage; // URL to larger image
    NSMutableData *receivedData;
    NSURLConnection *theConnection;
    NSURLRequest *request;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet RootViewController *rootViewController;
@property (nonatomic, readonly) RMMapContents *mapContents;


@end

Inside a function I see this line:

- (void)foo:(xyz *)abc{
  ..
  RMMapContents *mapContents = [self mapContents];
  ..
}

So, taking it from C++, the mapContents seem like it is not a global scope var (after all, that’s why they call them properties, right?), but isn’t defining the same name again inside the function weird a bit?

I hope someone can clarify a little here.
Thanks!

Answer 1

The scope of the @interface block extends upto the @end keyword and is not restricted to the braces {}.

So the @property declaration lies very much inside the scope of the @interface and like cli_hlt rightly answered, it acts like a substitute to setter and getter methods for the mapContents property.

so a property named mapContents, would have setters and getters which look like this :

- (void)setMapContents; //setter

- (RMMapContents *)mapContents; //getter

and would can be accessed from within the class using these methods:

[self setMapContents:newContents];

AND

RMMapContents *contents = [self mapContents];