CODEWITHSUNDEEP
iosobjective-cswiftobjective-c-blocksswift2
Dave Thomas
Dave Thomas

Reputation: 3837

Objective-C Block assigned from Swift is nil after assignment

This is highly related to other questions about accessing ObjC callbacks from Swift. But my research is yet to not yield working results.

Anyone able to see if I am possibly doing something wrong syntax wise here?

I've declare the following Objective-C callback as:

#import <UIKit/UIKit.h>

@class KxMovieDecoder;

typedef void (^KX_FIRST_FRAME_CALLBACK)() ;


extern NSString * const KxMovieParameterMinBufferedDuration;    // Float
extern NSString * const KxMovieParameterMaxBufferedDuration;    // Float
extern NSString * const KxMovieParameterDisableDeinterlacing;   // BOOL

@interface KxMovieViewController : UIViewController<UITableViewDataSource, UITableViewDelegate> {
    KX_FIRST_FRAME_CALLBACK firstFrameLoaded;
}

+ (id) movieViewControllerWithContentPath: (NSString *) path
                               parameters: (NSDictionary *) parameters;

@property (readonly) BOOL playing;
@property (nonatomic, copy) KX_FIRST_FRAME_CALLBACK firstFrameLoaded;

- (void) play;
- (void) pause;

@end

When I assign to it from swift code, it is still nil after assignment:

Image showing debug

public func startViewing() -> UIViewController {

        kxMoviePlayer = KxMovieViewController.movieViewControllerWithContentPath(rtspURL, parameters: nil) as? KxMovieViewController
        kxMoviePlayer!.firstFrameLoaded = {
            self.onFirstFrameOfVideo()
        }

Upvotes: 0

Views: 283

Answers (1)

Scott H
Scott H

Reputation: 1529

Just put together a blank project with a similar set up and it worked fine. A couple of questions though.

Did you mean to have both an instance variable and a property named firstFrameLoaded? Your auto-synthesized property is not using the instance variable and is instead using an auto-generated _firstFrameLoaded instance variable. Perhaps this is the source of the confusion and you meant to prefix the i-var with an underscore?

Any reason the callback property is a copy instead of indicating strong or weak referencing?

Upvotes: 1

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