How to use completion block using SDWebImage in Swift 3.0?

Question

Am using SDWebImage to download image. I want to do further operation if image is downloaded successfully.

cell.appIcon.sd_setImage(with: url, placeholderIma         


        

Answer 1

According to the typedef in the framework you're using:

typedef void(^SDExternalCompletionBlock)(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL);

an SDExternalCompletionBlock consists of optional parameters as indicated by _Nullable. Therefor your code should be written like this:

cell.appIcon.sd_setImage(with: url, placeholderImage: UIImage.init(named: "App-Default"), completed: {(image: UIImage?, error: NSError?, cacheType: SDImageCacheType, imageURL: URL?) -> Void in
      // Perform operation. 
})

Since the compiler knows the types of the completion block's parameters (from the function declaration) you can write the code more succinctly and (IMO) easier to read like this:

cell.appIcon.sd_setImage(with: url, placeholderImage: UIImage(named: "App-Default"), completed: { (image, error, cacheType, imageURL) in
      // Perform operation. 
})