using blocks that returns and takes a parameter

Question

So in AFNetworking there is a function as follows:

+ (AFImageRequestOperation *)imageRequestOperationWithRequest:(NSURLRequest *)urlRequest
                                         imageProcessingBlock:(UIImage *(^)(UIImage *))imageProcessingBlock
                                                    cacheName:(NSString *)cacheNameOrNil
                                                      success:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image))success
                                                      failure:(void (^)(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error))failure
{

I am trying to use it as follows:

 [AFImageRequestOperation imageRequestOperationWithRequest:nil imageProcessingBlock:^UIImage * (UIImage *) {

        }cacheName:@"nsurl" success:^(NSURLRequest *request, NSHTTPURLResponse * response, UIImage * image){

        }failure:^(NSURLRequest *request, NSHTTPURLResponse * response, NSError * error){

        }];

However it doesn't seem to be correct in the UIImage part.. any ideas?

Answer 1

You are almost there - your code was missing a parameter name for the image in the first block:

[AFImageRequestOperation imageRequestOperationWithRequest:nil imageProcessingBlock:^UIImage * (UIImage *image) { // <<== HERE

} cacheName:@"nsurl" success:^(NSURLRequest *request, NSHTTPURLResponse * response, UIImage * image){

}failure:^(NSURLRequest *request, NSHTTPURLResponse * response, NSError * error){

}];

I think this is a bug in Xcode, because it expanded the signature into precisely what you posted, without the parameter name.