Error with: override public func observeValueForKeyPath

Question

I am using code that worked with Xcode 7 Beta 2. Just got Beta 3 and now I'm getting this problem that seems like an Xcode bug?

For one of my public classes...

override public func observeValueForKeyPath...

Method does not override any method from its superclass

So I take out the "override":

public func observeValueForKeyPath

Method conflicts with method from superclass NSObject with the same Objective-C selector

ha! I was lied to by the first error. Won't compile either way. Any help please?

This may sound rudimentary, but have you cleaned your build folder (cmd-shift-k)? — Oxcug, Jul 09 '15 at 04:36
That didn't help, but matt's answer (change NSObject to String) fixed it. — 36 By Design, Jul 09 '15 at 05:04

score 31 · Answer 1 · edited Mar 29 '20 at 07:53

31

If the definition is copied from NSKeyValueObserving.h, your override would look like the below:

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
    // ...
}

Note: For methods like this one, you could usually press Cmd+Shift+O and go straight to Open Quickly... pop-up field where any definition could be copy/pasted and Xcode will search for it within the project/SDK. Watch for iOS scope in this case.

edited Mar 29 '20 at 07:53

pkamb

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answered Sep 24 '15 at 01:47

Yevhen Dubinin

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Thanks a lot. Not making the params Optional was the culprit and your answer definitely helped. – metpb Nov 23 '15 at 13:00
yeah +1 for the params needing to be optional – vtcajones Mar 24 '16 at 21:42
7

IOS:10 override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) { – Ryan Heitner Jan 05 '17 at 11:45

score 21 · Accepted Answer · answered Jul 09 '15 at 04:51

21

Change [NSObject:AnyObject] in the declaration to [String:AnyObject].

answered Jul 09 '15 at 04:51

matt

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Thanks that worked, sorry for the noob question but I greatly appreciate the help. – 36 By Design Jul 09 '15 at 05:03
It is not obvious to find out, my code completion does not work. I wish fuzzy autocomplete and alcatraz can be used again soon. :( – Harry Ng Aug 09 '15 at 05:49

Error with: override public func observeValueForKeyPath

2 Answers2