CODEWITHSUNDEEP
iosswiftasynchronousclosures
Jo Doe
Jo Doe

Reputation: 5

Swift: Completion Closure never executes?

So basically, I'm trying to get back the string that the function foobar returns. Originally, I had tried just returning the string from foobar, but swift kept returning early/asynchronously? from foobar. Code below: 

@IBAction func bAction(_ sender: UIButton) {
    print("this prints")
    foobar(completion: { (info) in
        print("this does not print")
    })
}

func foobar(completion: @escaping (_ info: String) -> ()) {
    var info = ""
    //insert code here
    print("this prints too")
    //insert more code here
}

What am I doing wrong?

Upvotes: 0

Views: 524

Answers (1)

rmaddy
rmaddy

Reputation: 318774

Since you never call the completion handler, it isn't called.

You need to call completion("some string literal or string variable") from within your foobar method.

func foobar(completion: @escaping (_ info: String) -> ()) {
    var result = ""

    print("this prints too")

    completion(result)
}

But keep in mind that a completion handler is only useful when there is some asynchronous processing going on. If foobar doesn't do anything asynchronously then you should not be setting this up to use a completion handler. A simple return value is all you need.

Upvotes: 7

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