Having issue calling delegate method and updating UI in the previous view controller

Question

I want to use a delegate method to update some UI in my top view controller from the current view controller. I'm getting error unexpectedly found nil while unwrapping an Optional value. Please have a look at the following code and suggest what's wrong.

First View Controller

Second View Controller

It's throwing error at sampleProtocol!.updateTextLabel(someText) — Vakas, Jul 07 '15 at 08:33
Refer this http://stackoverflow.com/questions/24643522/fatal-error-unexpectedly-found-nil-while-unwrapping-an-optional-values — Kathiravan G, Jul 07 '15 at 08:44

score 0 · Answer 1 · answered Jul 08 '15 at 04:04

I fixed it. I was missing prepareForSegue implementation in my first View Controller.

I had to assign the delegate to self in prepareForSegue. I can't do it like

let vc = SecondViewController()
vc.sampleProtocol = self

which I was doing in my viewDidLoad()

score 0 · Answer 2 · answered Jul 14 '15 at 07:07

0

You cannot set the delegate like you're doing in your code in viewDidLoad. You have to implement prepareForSegue and set your delegate there.

answered Jul 14 '15 at 07:07

Nick

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Having issue calling delegate method and updating UI in the previous view controller

2 Answers2