CODEWITHSUNDEEP
objective-cswiftios8objective-c-blocks
Marco Almeida
Marco Almeida

Reputation: 1303

How do I use enumerateObjectsUsingBlock in Swift

I am having trouble in converting this Block code from Objective C into Swift. I searched the web found some examples but none fixed the errors I get.

Any help would be appreciated.

- (void)didReceiveMemoryWarning {
    [[self.viewControllersByIdentifier allKeys] enumerateObjectsUsingBlock:^(NSString *key, NSUInteger idx, BOOL *stop) {
        if (![self.destinationIdentifier isEqualToString:key]) {
            [self.viewControllersByIdentifier removeObjectForKey:key];
        }
    }];
    [super didReceiveMemoryWarning];
}

Here is what I tried:

override func didReceiveMemoryWarning() {
    var array : NSArray = self.viewControllersByIdentifier.allKeys
    array.enumerateObjectsUsingBlock { (key, idx, stop) in
        if (![self.destinationIdentifier == key]) {
            self.viewControllersByIdentifier .removeObjectForKey(key)
        }
    }
    super.didReceiveMemoryWarning()
}

And the error I am getting is on the "if" statement and it tells me that "String is not convertible to "MirrorDisposition".

Upvotes: 2

Views: 787

Answers (2)

Airspeed Velocity
Airspeed Velocity

Reputation: 40965

You’ve left a bit of Objective-C in your Swift (some rogue square brackets):

if(![self.destinationIdentifier == key]) {

However, you would probably find it easier to use Swift’s for-in than array.enumerateObjectsUsingBlock:

override func didReceiveMemoryWarning() {
    for key in self.viewControllersByIdentifier.allKeys {
        // note key will be an AnyObject so you need to cast it to an appropriate type… 
        // also, this means you can use != rather than ! and ==
        if self.destinationIdentifier != key as? NSString {
            self.viewControllersByIdentifier.removeObjectForKey(key)
        }
    }
    super.didReceiveMemoryWarning()
}

Upvotes: 2

Mundi
Mundi

Reputation: 80265

Did you look at the documentation?

func enumerateObjectsUsingBlock(_ block: (AnyObject!,
                                     Int,
                                     UnsafeMutablePointer<ObjCBool>) -> Void)

Upvotes: 0

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