Store a swift closure as a property on an objective-c class where the block is declared using a typedef

Question

OMG, for the life of me I can't get this to work.

• I've got a typdef in objective-c that looks like this:

typedef void (^StringBlock)(NSString * string);

• I've got an objective-c class that has a property that allows you to store your own block of StringBlock type. That property is declared in objective-c like this:

@property (nonatomic, copy) StringBlock onTextSubmitBlock;

• Assigning a block to it in objective-c looks like this:

input.onTextSubmitBlock = ^(NSString * text) {

};

• I want to do the same thing from within a Swift class! The closest I've come to having something that works is this:

input!.onTextSubmitBlock = {(StringBlock) in

}

That compiles, but I have no access to the argument I need ((NSString * text) in objective-c...)

I'm sure that once I get used to Swift this will be obvious, but what am I missing?

Answer 1

You are pretty close. You should be able to use it like this:

input!.onTextSubmitBlock = { text in
    println(text)
}

Swift will infer that text is an NSString from the declaration. Thera are a couple alternative ways you could declare this as well. Like this:

input!.onTextSubmitBlock = {
    println($0) // $0 is text
}

And this:

input!.onTextSubmitBlock = { (text: NSString) -> () in
    println(text)
}