Swift: unexpectedly found nil while unwrapping an Optional value when setting delegate for UITextField object

Question

Update: with 2 downvote of this question, I'd like to make this question a little bit useful to others - since I don't have the choice to delete it. The mistake I made was cut and paste codes which has interface outlet. As I was completely new at that time, I was assuming that when I copy and paste, the outlet link will be copied and pasted as well. Obviously it doesn't work that way.

I was writing a single-viewed app. It has one UITextField and one MKMapView. I want to do something when Return key is hit, so I basically followed

How to hide keyboard in swift on pressing return key?

But it does not fit well with my other codes. Any idea why it isn't working and how to fix it?

code

How are you creating the instance of `ViewController` and triggering the view to load? — Wain, Apr 11 '15 at 19:52
The hollow circle says it isn't connected. Redo the CTRL+Drag thing to hook it up. — keithbhunter, Apr 11 '15 at 19:59
@keithbhunter U r right. For some reason, the searchText was not connected properly. Thank you :) — Danny Wang, Apr 11 '15 at 20:02
Post your code, not screenshots of your code. Post your errors, not screenshots of your errors. Screenshots in addition are nice, but please, post everything you can as plain text. — nhgrif, Apr 11 '15 at 20:39
The first, second, and third rule of iOS/Mac OS programming is check your outlets. — Duncan C, Apr 11 '15 at 20:40
@nhgrif turns out it is the screenshot that helped to locate the problem. — Danny Wang, May 22 '15 at 07:32
@DuncanC a lesson learned from this was never to Cut and Paste an outlet. — Danny Wang, May 22 '15 at 07:35

score 2 · Accepted Answer · answered Apr 11 '15 at 19:53

2

Make sure you connect your UITextField from StoryBoard to your searchText IBOutlet by control-dragging from the StoryBoard to the the searchText variable.

answered Apr 11 '15 at 19:53

chrissukhram

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score 1 · Answer 2 · edited Jun 20 '20 at 09:12

You have your outlet set up as implicitly unwrapped. That's the correct thing to do, but when your code executes the outlet must not be nil or your code will crash.

You probabably have a broken outlet link. Set a breakpoint and examine the outlet.

You can change your code to use an "if let" expression to prevent crashes. Search in the Swift language reference IBook for "Optional binding" to learn about it.

Edit:

The code might look like this:

if let requiredSerachText = searchtext
{
  requiredSearchText.delegate = self
}

Swift: unexpectedly found nil while unwrapping an Optional value when setting delegate for UITextField object

2 Answers2

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