Swift call Objective-C wrapper function containing blocks

Question

I have an Objective-C wrapper (ObjCWrapper.h and ObjCWrapper.m) with prototype

+ (void) login:(NSString *)username andPassword:(NSString *)password andErrorBlock:(SuccessBlock)errorBlock andSuccessBlock:(SuccessBlock)successBlock;

With typedef

typedef void (^SuccessBlock)(NSString *);

and implementation

+ (void)login:(NSString *)username andPassword:(NSString *)password andErrorBlock:(SuccessBlock)errorBlock andSuccessBlock:(SuccessBlock)successBlock
{
    // do stuff like
    successBlock(@"test");
}

From my swift view controller (ViewController.swift), I call the login function:

ObjCWrapper.login("abc", andPassword: "abc",
        andErrorBlock:
        {
            (error:String) -> Void in
            println();
        },
        andSuccessBlock:
        {
            (map:String) -> Void in
            println();
        }
    )

But I get error:

Cannot invoke 'login' with an argument list of type '(String, andPassword: String, andErrorBlock:(String)->void, andSuccessBlock:(String)->void)'

Searching in google says that I am passing some invalid types in the arguments, but I can't find anything wrong in the code. Removing the blocks from the function makes the code work, so I guess it is something related on the way of calling a block function.

Thanks for the help!

PS, don't use 'and' in Objective-C method name this way, refer developer.apple.com/library/ios/documentation/Cocoa/Conceptual/… — pinxue
– pinxue, Commented Sep 27, 2015 at 20:10

Adam · Accepted Answer · 2015-09-14 08:33:09Z

1

It might be worth adding nullability specifiers to your completion block:

typedef void (^SuccessBlock)( NSString * _Nonnull );

And to the method itself:

+ (void) login:(nonnull NSString *)username andPassword:(nonnull NSString *)password andErrorBlock:(nullable SuccessBlock)errorBlock andSuccessBlock:(nullable SuccessBlock)successBlock;

Then you should be able to call your method in Swift:

        ObjCWrapper.login("login", andPassword: "pass", andErrorBlock: { (error:String) -> Void in
        //error handling
        }) { (map:String) -> Void in
            //other stuff
    }

edited Sep 14, 2015 at 8:33

answered Sep 14, 2015 at 8:25

Adam

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1 Comment

Grace Over a year ago

Hi @Adam, thanks a lot for the help. But I still get the same error

Helge Becker · Accepted Answer · 2015-09-21 12:25:23Z

0

Obj-C NSString != Swift String With other word, you pass a String where a NSString is expected. Casting it down should solve that.

answered Sep 21, 2015 at 12:25

Helge Becker

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Comments

Grace · Accepted Answer · 2015-09-22 07:28:11Z

0

This is what I ended up doing

let username = "username" //usernameField.text
let password = "password" //passwordField.text

        ObjCWrapper.login(username, andPassword: password,
            andErrorBlock:
            {
                (map) -> Void in
                // stuff
            })
            {
                (map) -> Void in
                // stuff
            }

answered Sep 22, 2015 at 7:28

Grace

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