如何使函数在swift中返回它的内部闭包值

Question

如何从downloadedImage返回beginGetImageRequest。

func beginGetImageRequest() {

    if let imagePath = thumbPath {
        request = Alamofire.request(.GET, imagePath).response(completionHandler: { (_, _, imageData, error) -> Void in
            if error != nil {
                NSLog("Error downloading thumbnail image: \(error)")
            } else {
                if let downloadedImage = UIImage(data: imageData!) {
                    self.imageView.image = downloadedImage
                }
            }
        })
    }
}

Answer 1

误解了请求，我将其编辑为agian：

func beginGetImageRequest(completion:(_ image:UIImage)->()){

    if let imagePath = thumbPath {
        request = Alamofire.request(.GET, imagePath).response(completionHandler: { (_, _, imageData, error) -> Void in
            if error != nil {
                NSLog("Error downloading thumbnail image: \(error)")
            } else {
                if let downloadedImage = UIImage(data: imageData!) {
                    completion(downloadedImage)
                }
            }
        })
    }
}

调用方法时：

beginGetImageRequest { (image:UIImage) in
        // code you need
    }