converting NSArray to RLMArray with RKValueTransFormer fails converting outputValue to AutoreleasingUnsafeMutablePointer

问题

I am using RestKit and realm.io together. I have an array of values (the array is url strings of pictures) being returned in JSON that should become a RLMArray of RLMObjects. I believe the mappings are set up correctly because it makes an attempt to convert the results to an RLMArray. But I get the following error from RestKit:

restkit.object_mapping:RKMappingOperation.m:449 Failed transformation of value at keyPath 'picList' to representation of type 'RLMArray': Error Domain=org.restkit.RKValueTransformers.ErrorDomain Code=3002 "Failed transformation of value '(
"Picture {\n\turl = ;\n\tremote_url = http://placekitten.com/g/500/500;\n}",
"Picture {\n\turl = ;\n\tremote_url = http://placekitten.com/g/400/400;\n}",
"Picture {\n\turl = ;\n\tremote_url = http://placekitten.com/g/300/300;\n}"
)' to RLMArray: none of the 2 value transformers consulted were successful."

So I created a value transformer to perform the transformation manually. Here is my code:

func setupValueTransformerForPicList(){

    println("called value transformer function")
    var picListValueTransformer = RKBlockValueTransformer(validationBlock: { (inputClass:AnyClass!,outputClass:AnyClass!) -> Bool in

        if (inputClass.className() == "Array" || inputClass.className() == "__NSArrayM") && outputClass.className() == "RLMArray" {
            return true
        }
        return false

        }) { (inputValue:AnyObject!, var outputValue, outputClass, error) -> Bool in

            println("called value transformer")
            if let thisArray:NSArray = inputValue as? NSArray{
                var picRlmArray:RLMArray = RLMArray(objectClassName: Picture.className())
                for item in thisArray {
                    if let thisPicture:Picture = item as? Picture{
                        picRlmArray.addObject(thisPicture)
                    } else {
                        return false

                    }
                }
                outputValue = picRlmArray // this is the line that throws the error
                return true
            }
            return false
    }
    RKValueTransformer.defaultValueTransformer().addValueTransformer(picListValueTransformer)
}

However, I get the error message:

'RLMArray' is not convertible to 'AutoreleasingUnsafeMutablePointer<AnyObject?>'

I've tried downcasting

 outputValue = picRlmArray as AutoreleasingUnsafeMutablePointer<AnyObject?>

with the same result. I've tried doing whatever this is (if it's even a thing)

outputValue = picRlmArray as AutoreleasingUnsafeMutablePointer<RLMArray?>

and get the error

'RLMArray' is not identical to 'AnyObject'

I'm a little out of my depth here, but feel like this should definitely be achievable. Any help would be greatly appreciated. Thank you!

EDIT:

I'm also unable to return a swift array from this function. It gives the same error. I think this might be a more general question about how to return types that aren't AnyObjects.

回答1:

I'm the current maintainer of RestKit, and I'm sad to say that I haven't had much of a chance to play around with using RestKit and Realm together, especially not with Swift.

I'll take a look at what might be causing this error.

EDIT:

It seems to me that doing outputValue.memory = picRlmArray instead of outputValue = picRlmArray would do the trick!

来源：https://stackoverflow.com/questions/27302925/converting-nsarray-to-rlmarray-with-rkvaluetransformer-fails-converting-outputva

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swift