swift - 如何使用 AlamofireImage ProgressHandler

Question

我很难弄清楚如何准确定义 ProgressHandler 参数。 typealias 定义为public typealias ProgressHandler = (bytesSent: Int64, totalBytesSent: Int64, totalExpectedBytes: Int64) -> Void 可以在此处找到更多信息 https://github.com/Alamofire/AlamofireImage/pull/91

let URLRequest = NSURLRequest(URL: NSURL(string: "https://httpbin.org/image/jpeg")!)
    ImageDownloader().downloadImages(URLRequests: [URLRequest], filter: nil,
 progress: (init progress here), progressQueue: dispatch_get_main_queue(), completion: {
            _ in
        })

不是重复的!引用的答案/问题是导致实现此功能的原因 https://stackoverflow.com/a/33503205/5222077

Answer 1

像在 Swift 中定义任何闭包一样定义它。你可以给捕获的参数任何你想要的名字，或者使用 _ 没有，但你需要有 3 个。例如:

ImageDownloader().downloadImage(URLRequest: "http://httpbin.org/image/png", progress: { (bytesRead, totalBytesRead, totalExpectedBytesToRead) in
    print("Read:\(bytesRead), Total Read: \(totalBytesRead), Expected: \(totalExpectedBytesToRead)")
})