Can someone help me fully understand this example?

Question

Just to clarify the usage concept in this animation example. The animateWithDuration function accepts a closure parameter as a callback:
```swift
 animations: { () -> Void in
    someLabel.alpha = 0.3
    }
```
That's ok I got it.
But what's the second closure? Is it a parameter? For what function?
```swift
{ (failure: Bool) -> Void in}
```

Jhoan Arango · Accepted Answer

Hello:
What you are looking at is a "class method".
```swift
class func animateWithDuration(_ duration: NSTimeInterval,
                    animations animations: () -> Void,
                    completion completion: ((Bool) -> Void)?) 
```
This class method has 3 parameters which takes block objects (closures) as it's arguments. The first parameter is not a closure, but the subsequent parameters are. The completion parameter takes a block object to be executed when the animation sequence ends. This block has no return value and takes a single Boolean argument that indicates whether or not the animations actually finished before the completion handler was called.
Hope this helps

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Marcos Reboucas

Marcos Reboucas

Can someone help me fully understand this example?

1 Answer

Jhoan Arango

Jhoan Arango