您好，我有适用于 swift2.2 的 json 解析代码，但是当我将其用于 Swift 3.0 时，会给我这个错误
ViewController.swift：132：31：对成员"dataTask（with：completionHandler：）"的不明确引用
我的代码在这里：
let listUrlString = "http://bla.com?batchSize=" + String(batchSize) + "&fromIndex=" + String(fromIndex)
let myUrl = URL(string: listUrlString);
let request = NSMutableURLRequest(url:myUrl!);
request.httpMethod = "GET";
let task = URLSession.shared().dataTask(with: request) {
data, response, error in
if error != nil {
print(error!.localizedDescription)
DispatchQueue.main.sync(execute: {
AWLoader.hide()
})
return
}
do {
let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSArray
if let parseJSON = json {
var items = self.categoryList
items.append(contentsOf: parseJSON as! [String])
if self.fromIndex < items.count {
self.categoryList = items
self.fromIndex = items.count
DispatchQueue.main.async(execute: {
self.categoriesTableView.reloadData()
AWLoader.hide()
})
}else if( self.fromIndex == items.count){
DispatchQueue.main.async(execute: {
AWLoader.hide()
})
}
}
} catch {
AWLoader.hide()
print(error)
}
}
task.resume()
感谢您的想法。
编译器对函数签名感到困惑。你可以这样修复它：
let task = URLSession.shared.dataTask(with: request as URLRequest) {
但是，请注意，如果之前声明为 URLRequest 而不是 NSMutableURLRequest，我们不必在此签名中将"request"转换为URLRequest：
var request = URLRequest(url:myUrl!)
这是NSMutableURLRequest和新URLRequest之间的自动转换，它失败了，迫使我们在这里进行这种转换。
你有 init 会myRequest NSMutableURLRequest ，你需要这个：
var URLRequest
斯威夫特正在抛弃这两件事NSMutable...。只需将var用于新类即可。
Xcode 8 和 Swift 3.0
使用 URLSession：
let url = URL(string:"Download URL")!
let req = NSMutableURLRequest(url:url)
let config = URLSessionConfiguration.default
let session = URLSession(configuration: config, delegate: self, delegateQueue: OperationQueue.main)
let task : URLSessionDownloadTask = session.downloadTask(with: req as URLRequest)
task.resume()
网址委托调用：
func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
}
func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask,
didWriteData bytesWritten: Int64, totalBytesWritten writ: Int64, totalBytesExpectedToWrite exp: Int64) {
print("downloaded (100*writ/exp)" as AnyObject)
}
func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL){
}
使用块获取/发布/放置/删除：
let request = NSMutableURLRequest(url: URL(string: "Your API URL here" ,param: param))!,
cachePolicy: .useProtocolCachePolicy,
timeoutInterval:"Your request timeout time in Seconds")
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers as? [String : String]
let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest) {data,response,error in
let httpResponse = response as? HTTPURLResponse
if (error != nil) {
print(error)
} else {
print(httpResponse)
}
DispatchQueue.main.async {
//Update your UI here
}
}
dataTask.resume()
对我来说工作正常..尝试100%结果保证
此问题是由 URLSession 有两个 dataTask 方法引起的
open func dataTask(with request: URLRequest, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Swift.Void) -> URLSessionDataTask
open func dataTask(with url: URL, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Swift.Void) -> URLSessionDataTask
第一个有URLRequest作为参数，第二个有URL作为参数，所以我们需要指定调用哪个类型，比如我想调用第二个方法
let task = URLSession.shared.dataTask(with: url! as URL) {
data, response, error in
// Handler
}
在我的情况下，错误是在 NSURL 中
let url = NSURL(string: urlString)
在 Swift 3 中，你只需要编写 URL：
let url = URL(string: urlString)
测试的 xcode 8 稳定版;需要将var request变量与URLRequest()一起使用 有了它，您可以轻松修复它（错误）
var request = URLRequest(url:myUrl!)和
let task = URLSession.shared().dataTask(with: request as URLRequest) { }
工作正常！谢谢你们，我想帮助了很多人。!
对于 Swift 3 和 Xcode 8：
var dataTask: URLSessionDataTask?
if let url = URL(string: urlString) {
self.dataTask = URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in
if let error = error {
print(error.localizedDescription)
} else if let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200 {
// You can use data received.
self.process(data: data as Data?)
}
})
}
}
注意：您可以随时使用调试器来检查错误
在 swift 3 中，编译器被函数签名混淆了。指定它将清除错误。同时将网址字符串转换为类型 URL。以下代码对我有用。
let urlString = "http://bla.com?batchSize="
let pathURL = URL(string: urlString)!
var urlRequest = URLRequest(url:pathURL)
let session = URLSession.shared
let dataTask = session.dataTask(with: urlRequest as URLRequest) { (data,response,error) in
Swift 3 的简短答案：
guard let requestUrl = URL(string: yourURL) else { return }
let request = URLRequest(url:requestUrl)
URLSession.shared.dataTask(with: request) {
(data, response, error) in
...
}.resume()
// prepare json data
let mapDict = [ "1":"First", "2":"Second"]
let json = [ "title":"ABC" , "dict": mapDict ] as [String : Any]
let jsonData : NSData = NSKeyedArchiver.archivedData(withRootObject: json) as NSData
// create post request
let url = NSURL(string: "http://httpbin.org/post")!
let request = NSMutableURLRequest(url: url as URL)
request.httpMethod = "POST"
// insert json data to the request
request.httpBody = jsonData as Data
let task = URLSession.shared.dataTask(with: request as URLRequest){ data,response,error in
if error != nil{
return
}
do {
let result = try JSONSerialization.jsonObject(with: data!, options: []) as? [String:AnyObject]
print("Result",result!)
} catch {
print("Error -> (error)")
}
}
task.resume()
要通过GET请求加载数据，您不需要任何URLRequest（也没有分号）
let listUrlString = "http://bla.com?batchSize=" + String(batchSize) + "&fromIndex=" + String(fromIndex)
let myUrl = URL(string: listUrlString)!
let task = URLSession.shared.dataTask(with: myUrl) { ...
let task = URLSession.shared.dataTask(with: request as URLRequest, completionHandler: { data,response,error in
if error != nil{
print(error!.localizedDescription)
return
}
if let responseJSON = (try? JSONSerialization.jsonObject(with: data!, options: [])) as? [String:AnyObject]{
if let response_token:String = responseJSON["token"] as? String {
print("Singleton Firebase Token : (response_token)")
completion(response_token)
}
}
})
task.resume()
Xcode 10.1 Swift 4
这对我有用：
let task: URLSessionDataTask = session.dataTask(with: request as URLRequest) { (data, response, error) -> Void in
...
键正在添加URLSessionDataTask类型声明。
对我来说，
我这样做是为了找到，
let url = URL(string: urlString)
URLSession.shared.dataTask(with: url!) { (data, response, error) in ...}
不能使用
"let url = NSURL(string: urlString)