CODEWITHSUNDEEP
iphoneobjective-ciosnsuserdefaultskey-value
SmartTree
SmartTree

Reputation: 1471

Value for key is nil. Why?

Good morning, I made an IBAction method which saves some objects to an array:

-(IBAction)saveToFav:(id)sender
{
    NSUserDefaults *newDefaults = [NSUserDefaults standardUserDefaults];
    favorites = [[NSMutableArray alloc]initWithArray:[newDefaults mutableArrayValueForKey:@"favorites"] copyItems:YES];

    // check if array already contains an object

    if (![favorites containsObject:self.title])
    {
        [favorites addObject:self.title];
    }
    [newDefaults setObject:favorites forKey:@"favorites"];
}

However, when I call this method app crashes with error:

[NSKeyValueSlowMutableArray getObjects:range:]: value for key favorites of object 0x8939030 is nil'

Why this happens ? Thanks!

Max

Upvotes: 0

Views: 863

Answers (4)

TompaLompa
TompaLompa

Reputation: 949

When your app finishes loading add this:

NSMutableArray *array = [[NSMutableArray alloc]init]; 
[defaults setObject:array forKey:@"favorites"]; 
[defaults synchronize];

Upvotes: 1

TompaLompa
TompaLompa

Reputation: 949

It seems like your data (favorites) has not been written to your defaults.You can forcesave your defaults by running this:

[[NSUserDefaults standardUserDefaults] synchronize];

Upvotes: 2

Jeff Wolski
Jeff Wolski

Reputation: 6372

In this line

favorites = [[NSMutableArray alloc]initWithArray:[newDefaults mutableArrayValueForKey:@"favorites"] copyItems:YES];

nil is being assigned to favorites. The reason for this is that newDefaults is only just built on the previous line and is empty.

Upvotes: 1

TompaLompa
TompaLompa

Reputation: 949

newDefaults is nil for key "favorites".

Upvotes: 1

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