animateWithDuration:animations:completion: in Swift

Question

In objective-C my animation bit would look something like this:

[UIView animateWithDuration:0.5 animations:^{
            [[[_storedCells lastObject] topLaye         


        

Answer 1

This is a good one, tricky!

The issue is in your completion block...

A. I would begin by rewriting it like this: (not the final answer, but on our way there!)

{ _ in self.storedCells.removeAtIndex(1) }

(the _ in place of the "finished" Bool, to indicate to the reader that its value isn't being used in the block - you may also consider adding a capture list as necessary to prevent a strong reference cycle)

B. The closure you have written has a return type when it shouldn't! All thanks to Swift's handy feature "implicit returns from single expression closures" - you are returning the result of that expression, which is the element at the given index

(the type of the closure argument for completion should be ((Bool) -> Void))

This can be resolved as so:

{ _ in self.storedCells.removeAtIndex(1); return () }