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

Posted by Brendan Corey
Brendan Corey
Courses Plus Student 5,745 Points

Not understanding what I am doing wrong with question 3 of 3 in 'Creating a Data Collection'

shoppingCart = [shoppingList objectAtIndex:2];

ViewController.h 
#import "UIViewController.h"

@interface ViewController : UIViewController

@property (strong, nonatomic) NSString *shoppingCart;
@property (strong, nonatomic) NSArray *shoppingList;

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

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // Add your code below!

    self.shoppingList = @[@"toothpaste", @"bread", @"eggs"];

    shoppingCart = [shoppingList objectAtIndex: 2];
}

@end

1 Answer

Holger Liesegang
Holger Liesegang
50,595 Points
Holger Liesegang
Holger Liesegang
50,595 Points

Hi Brendan Corey !

You solved Challenge Task 3 of 3 "We're at the grocery store shopping and we found the eggs. In the header file we have a property, shoppingCart, of type NSString. In the viewDidLoad method, retrieve the string eggs from the shoppingList array and store it in shoppingCart. Hint: use the 'objectAtIndex' method." nearly complete. You only forgot to use "self" while referencing the properties of the class: self.shoppingCart = [self.shoppingList objectAtIndex: 2];

ViewController.h 
#import "ViewController.h"
#import "UIViewController.h"

@interface ViewController : UIViewController

@property (strong, nonatomic) NSString *shoppingCart;
@property (strong, nonatomic) NSArray *shoppingList;
@end
ViewController.m 
#import "ViewController.h"

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // Add your code below!
    self.shoppingList = @[@"toothpaste", @"bread", @"eggs"];
    self.shoppingCart = [self.shoppingList objectAtIndex: 2];
}

@end
Brendan Corey
Brendan Corey
Courses Plus Student 5,745 Points

Appreciate the assistance. Tried everything. was unaware about using the self.shoppingList objectAtIndex: 2 dot notation within the parentheses.

hamza shaikh
hamza shaikh
5,875 Points
hamza shaikh
hamza shaikh
5,875 Points

just want to lest you know i also was having trouble with the task 3 but you helped me out thankyou, but i'm a little confuse because in the video when added an array to the label he did not used self.

 (IBAction)showFacts {
    NSArray *facts = [[NSArray alloc]initWithObjects:@"this is a fact",@"this is another fact", nil];
    self.factsLabel.text = [facts objectAtIndex:1];
}

code worked fine even though i did'nt add self. to "[facts objectAtIndex:1]" it will really help me if you can clarify this for me thank you.

Michael Acosta Pegoraro
Michael Acosta Pegoraro
4,911 Points
Michael Acosta Pegoraro
Michael Acosta Pegoraro
4,911 Points

I was not aware about the self.shoppingList either. Good thing the answer was here and I found out after a while.