Ios 在执行segue之前,如何检查服务器响应值
这是我在UploadModel.swift中的代码Ios 在执行segue之前,如何检查服务器响应值,ios,swift,asynchronous,Ios,Swift,Asynchronous,这是我在UploadModel.swift中的代码 func uploadSpecialistWithId(login: String, password: String) { let requestUrl = URL(string: "http://localhost:3000/api/register/specialist")! var request = URLRequest(url: requestUrl) request.httpMeth
func uploadSpecialistWithId(login: String, password: String) {
let requestUrl = URL(string: "http://localhost:3000/api/register/specialist")!
var request = URLRequest(url: requestUrl)
request.httpMethod = "POST"
let postParams = "login=\(login)&password=\(password)"
print(postParams)
request.httpBody = postParams.data(using: String.Encoding.utf8)
let task = URLSession.shared.dataTask(with: request) {(data, response, error)
in
if(error != nil) {
print("error -> \(error!.localizedDescription)")
} else {
print("data uploaded")
self.parseJSONSpecialistResponse(data: data!)
}
}
task.resume()
}
func parseJSONSpecialistResponse(data: Data) {
var jsonResult = NSDictionary()
let specialist = Specialist()
do {
jsonResult = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! NSDictionary
} catch let error as NSError {
print("error -> \(error.localizedDescription)")
}
let items = NSMutableArray()
if let login = jsonResult["login"] as? String,
let specialistId = jsonResult["_id"] as? String {
specialist.login = login
specialist.specialistId = specialistId
print("Added \(specialist.itemDescribtion())")
items.add(specialist)
} else {
let errorCode = jsonResult["code"] as! Int
print("Erorr with code -> \(errorCode)")
items.add(errorCode)
}
DispatchQueue.main.async(execute: { () -> Void in
self.delegate.itemsUploaded(items: items)
})
}
但是,当我试图用现有登录名注册专家时,segue在我处理服务器响应之前已经执行了。我应该改变什么来解决这个问题?这是我在ViewController.swift中的代码
func itemsUploaded(items: NSArray) {
if let errorCode = items[0] as? Int {
if errorCode == 11000 {
warningLabel.text = "This login is already used"
error = true
}
}
if let specialist = items[0] as? Specialist {
self.specialistId = specialist.specialistId!
print("Value after itemsUploaded --> \(self.specialistId)")
}
}
@IBAction func doneButtonTouched(_ sender: Any) {
uploadModel.uploadSpecialistWithId(login: loginTextField.text!, password: passwordTextField.text!)
if(error == false) {
print("Segue perform value -> \(specialistId)")
performSegue(withIdentifier: "regToRegCompleteSegue", sender: self)
}
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let destination = segue.destination as! RegistrationCompleteViewController
print("Segue prepare value -> \(specialistId)")
destination.specialistId = self.specialistId
}
我知道我有这个问题是因为dataTask的异步性。但是,当self.delegate已经在主队列中时,为什么它不工作呢
编辑:添加completionHandler并没有解决我的问题,但Kamran的提议正在发挥作用。您应该在ItemsUpload内调用PerformScheue,一旦它只有在数据准备好时才会被调用
另一种方法是在函数parseJSONSpecialistResponse中使用@escaping来知道它何时完成。在完成块内,您可以调用performsgue。当您完成响应时,您应该执行segue,方法是移动
itemsupload
中的以下行,如下所示
@IBAction func doneButtonTouched(_ sender: Any) {
uploadModel.uploadSpecialistWithId(login: logiTextField.text!, password: passwordTextField.text!)
}
func itemsUploaded(items: NSArray) {
if let errorCode = items[0] as? Int {
if errorCode == 11000 {
warningLabel.text = "This login is already used"
error = true
}
}
if let specialist = items[0] as? Specialist {
self.specialistId = specialist.specialistId!
print("Value after itemsUploaded --> \(self.specialistId)")
}
if(error == false) {
print("Segue perform value -> \(specialistId)")
performSegue(withIdentifier: "regToRegCompleteSegue", sender: self)
}
}
这不是答案。任何函数的输入参数中都没有闭包,因此没有标记为
@escaping
。的可能重复。你的问题是由同样的事情引起的,解决方法也是一样的。当异步网络请求完成时,使uploadSpecializeTwithid
调用完成处理程序,并从完成处理程序内部调用performsgue
。