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iOS Build a Simple iPhone App with Objective-C Creating a Data Model Creating a Data Collection

Posted by Jessie Cui
Jessie Cui
7,607 Points

what does it mean to add the property to the header file?

I am so confused??

ViewController.h 
#import "UIViewController.h"

@interface ViewController : UIViewController

@property (strong, nonatomic) NSString *shoppingCart;

@end
ViewController.m 
#import "ViewController.h"

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    NSArray *shoppingList = @[@"nonatomic", @"strong"];
}

@end

1 Answer

Nathan Tallack
Nathan Tallack
22,160 Points
Nathan Tallack
Nathan Tallack
22,160 Points

So when you create a property inside a class file (that's your .m file) you want to declare it inside your header file also so that other parts of your code that load the header will understand the property is there inside the class file without having to parse the class file.

So by looking at the header only you can see there is a property of shoppingCart, which is an NSString, that is a member of the class ViewController. And your compiler (and more importantly you) did not need to parse the whole class file to know that.

Do note the discrepency in your code though. In your header you say the shoppingCart property is an NSString type, and in the class you declaring it as an NSArray type. That would be a problem. ;)