ios - 在执行 AFNetwork 请求之前执行 UI 更改

Question

我在登录 View Controller 中有一个 UIButton，当按下它时，从 UITextField 获取值并通过 AFNetwork 向服务器执行 POST 请求。我想在按下按钮后立即隐藏文本字段并显示 UIActivityIndi​​catorView，以便用户看到正在发生的事情。

问题是，请求是异步的，甚至在我更新 UI 之前就发生了。所以请帮我找到一种方法来实现所需的行为

pwdTextField.hidden = true

// Start the activity indicator
activityIndicator.startAnimating()    

// How can I make this happen before the actual request?    

let token = pwdTextField.text.trim()
let requestURL = "https://myapi.com/authenticate/"

manager.POST(requestURL, parameters: [ "code" : token ], success: { (operation: AFHTTPRequestOperation!, responseObject: AnyObject!) in
       NSLog("Success! Response is \(responseObject.description)")
}, failure: { (operation: AFHTTPRequestOperation!, error: NSError!) in
       println("Failure! Error is: \(error.localizedDescription)")
       self.displayLoginAttempErrorAlert()
}).waitUntilFinished()

Answer 1

删除 waitUntilFinished().. 它会阻止当前线程的执行，直到操作对象完成其任务..

manager.POST(requestURL, parameters: [ "code" : token ], success: { (operation: AFHTTPRequestOperation!, responseObject: AnyObject!) in
   NSLog("Success! Response is \(responseObject.description)")
 }, 
 failure: { (operation: AFHTTPRequestOperation!, error: NSError!) in
   println("Failure! Error is: \(error.localizedDescription)")
   self.displayLoginAttempErrorAlert()
 })