Swift function containing parameters not available in Objective-C class

Question

UPDATE: This question does not duplicate the question mentioned above. It was verified (see comment below) that the method definition IS properly added to the Project-Swift.h file. The question pertains to why the method without parameters is available to Obj-C and with parameters it is not.

I have a swift class that is intended to be referenced by an Objective-C class. The Swift class contains a function that will be used to send a network message and return a dictionary containing search results. I'm experiencing odd behavior in that if my function contains parameters, it is not available in the implementing Objective-C class. However, if I remove all the parameters, then the function becomes available.

In my Swift class if I declare the method as follows, it is not available in the Obj-C class and won't compile:

func getSearchResults(searchText:String?, searchType:String?, zoom:Int?) -> NSDictionary

However, removing the parameters like this, the function becomes avaiable to Obj-c and everything works:

func getSearchResults() -> NSDictionary

Why would a function without parameters be available to an Obj-C class while one containing parameters is not? Has anyone seen this kind of behavior? Thanks!

1. Try it without the Int? parameter -- maybe it can't translate that. 2. Check your Project-Swift.h file (the generated header -- replace Project with your project's name) -- see if getSearchResults is there and how it is declared -- maybe it's just not something you expected. — Lou Franco
– Lou Franco, Commented May 17, 2016 at 18:14
I checked the Project-Swift.h file and the method is properly declared: - (NSDictionary * _Nonnull)getSearchResults:(id _Nonnull)searchText searchType:(id _Nonnull)searchType zoom:(NSInteger)zoom; — Pheepster
– Pheepster, Commented May 17, 2016 at 18:21
@Pheepster: I have double-checked it. - (NSDictionary * _Nonnull)getSearchResults:(NSString * _Nullable)searchText searchType:(NSString * _Nullable)searchType zoom:(NSInteger)zoom; is declared in Project-Swift.h only if you make the last parameter non-optional zoom: Int (or if you remove that parameter). — Martin R
– Martin R, Commented May 17, 2016 at 19:30

Aseider · Accepted Answer · 2016-05-17 18:19:42Z

4

The bad boy in your parameter list is the Int? param. Int's are represented as NSInteger in Objective-C. Thus they don't have a pointer and can't have a null value. Consider removing the optional qualifier or changing it to NSNumber?, like: func getSearchResults(searchText: String?, searchType: String?, zoom: Int) -> NSDictionary

answered May 17, 2016 at 18:19

Aseider

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2 Comments

Pheepster Over a year ago

This does make sense, however, even this won't compile: func getSearchResults(searchText:NSString) -> NSDictionary

Pheepster Over a year ago

Seems that having any parameter at all causes it to be unavailable

matt · Accepted Answer · 2016-05-17 18:18:07Z

2

Lou Franco's explanation is correct. Your function has an Int? parameter, and there is no equivalent of that in Objective-C. Therefore the entire function cannot be exposed to Objective-C. Use Int or, if it really can be nil, use NSNumber?.

answered May 17, 2016 at 18:18

matt

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1 Comment

matt Over a year ago

And I would advise using String or NSString? instead of String? as well, because Swift 3 is going to be even stricter about this sort of thing.

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