我正在下载并读取一个json文件。这个json包含文件列表及其在服务器上的地址。
但是我在设置一个completionblock时遇到了一些麻烦,它会指示所有的事情都完成了。
jsonAnalysis {
self.sum = self.sizeArray.reduce(0, +)
print(self.sum)
} here
func jsonAnalysis(completion: @escaping () -> ()) {
let urlString = "xxxxxxxxxxxxxxxxxxxxx"
let url = URL(string: urlString)
URLSession.shared.dataTask(with:url!) { (data, response, error) in
if error != nil {
print("error")
} else {
do {
let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? [String: Any]
self.i = -1
guard let array = json?["Document"] as? [Any] else { return }
for documents in array {
self.i = self.i + 1
guard let VersionDictionary = documents as? [String: Any] else { return }
guard let DocumentName = VersionDictionary["documentname"] as? String else { return }
guard let AddressServer = VersionDictionary["addressserver"] as? String else { return }
self.resultAddressServer.append(AddressServer)
self.addressServer = self.resultAddressServer[self.i]
self.resultDocumentName.append(DocumentName)
self.documentName = self.resultDocumentName[self.i]
let url1 = NSURL(string: AddressServer)
self.getDownloadSize(url: url1! as URL, completion: { (size, error) in
if error != nil {
print("An error occurred when retrieving the download size: \(String(describing: error?.localizedDescription))")
} else {
self.sizeArray.append(size)
print(DocumentName)
print("The download size is \(size).")
}
})
}
} catch {
print("error")
}
}
completion()
} .resume()
}
func getDownloadSize(url: URL, completion: @escaping (Int64, Error?) -> Void) {
let timeoutInterval = 5.0
var request = URLRequest(url: url,
cachePolicy: .reloadIgnoringLocalAndRemoteCacheData,
timeoutInterval: timeoutInterval)
request.httpMethod = "HEAD"
URLSession.shared.dataTask(with: request) { (data, response, error) in
let contentLength = response?.expectedContentLength ?? NSURLSessionTransferSizeUnknown
completion(contentLength, error)
}.resume()
}
我想在最后得到数组的总和,当一切都完成后,马上打印(自我总和)正在运行并显示0。