方法更新巨大的延遲後的用戶界面

Question

我有一個UIView作爲父母和UIActivityIndicator作爲子視圖。每當用戶提交憑證，我開始活動動畫，並在方法名稱startLoadingAnimator()中分配父視圖alpha = 1.0它之後它調用一個API，當API完成調用時，我設置爲通過停止它並設置在名爲stopLoadingAnimator()的方法中父視圖的alpha = 0.0。 問題是stopLoadingAnimator()在其時間調用完美，但屏幕上的效果顯示延遲後 它應該就像方法運行時它應該消失在那個瞬間，但它需要很長時間消失。

停止活動動畫。

func stopLoadingAnimator() -> Void { 
    UIView.animateWithDuration(0.25, animations: { 

     self.loadingView.alpha = 0 
     self.activityIndicator.stopAnimating() 
    }) 



} 

啓動活動的動畫。

func startLoadingAnimator() -> Void { 
    UIView.animateWithDuration(0.25, animations: { 

     self.loadingView.alpha = 1 
     self.activityIndicator.startAnimating() 

    }) 
} 

API方法

func connectToWebWith(username:String, password:String) -> Void { 
     self.startLoadingAnimator() 
     let params = ["email":username, "password":password] 

//  params.setValue(username, forKey: "email") 
//  params.setValue(password, forKey: "password") 

     let request = NSMutableURLRequest(URL: NSURL(string: "https://callvabo.com/user/signin")!) 
     let session = NSURLSession.sharedSession() 
     request.HTTPMethod = "POST" 

     do { 
      request.HTTPBody = try NSJSONSerialization.dataWithJSONObject(params, options: .PrettyPrinted) 
     } catch { 
      self.stopLoadingAnimator() 

      //handle error. Probably return or mark function as throws 
      print(error) 
      return 
     } 
     request.addValue("application/json", forHTTPHeaderField: "Content-Type") 
     request.addValue("application/json", forHTTPHeaderField: "Accept") 

     let task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in 
      // handle error 
      self.stopLoadingAnimator() 
      guard error == nil else { 
       return 
      } 

      print("Response: \(response)") 
      let strData = NSString(data: data!, encoding: NSUTF8StringEncoding) 
      print("Body: \(strData)") 

      let json: NSDictionary? 
      do { 
       json = try NSJSONSerialization.JSONObjectWithData(data!, options: .MutableLeaves) as? NSDictionary 
      } catch let dataError { 
       // Did the JSONObjectWithData constructor return an error? If so, log the error to the console 
       print(dataError) 
       let jsonStr = NSString(data: data!, encoding: NSUTF8StringEncoding) 
       print("Error could not parse JSON: '\(jsonStr)'") 
       // return or throw? 
       return 
      } 


      // The JSONObjectWithData constructor didn't return an error. But, we should still 
      // check and make sure that json has a value using optional binding. 
      if let parseJSON = json { 
       // Okay, the parsedJSON is here, let's get the value for 'success' out of it 
       let success = parseJSON["success"] as? Int 
       print("Succes: \(success)") 
      } 
      else { 
       // Woa, okay the json object was nil, something went worng. Maybe the server isn't running? 
       let jsonStr = NSString(data: data!, encoding: NSUTF8StringEncoding) 
       print("Error could not parse JSON: \(jsonStr)") 
      } 

     }) 

     task.resume() 
    } 

Answer 1

更新您的啓動和停止動畫的方法，所以他們總是在主線程像這樣上執行：

停止活動動畫。

func stopLoadingAnimator() -> Void { 
    dispatch_async(dispatch_get_main_queue(), ^(){ 
     //Add method, task you want perform on mainQueue 
     //Control UIView, IBOutlet all here 

     UIView.animateWithDuration(0.25, animations: { 
      self.loadingView.alpha = 0 
      self.activityIndicator.stopAnimating() 
     }) 
    }) 
} 

啓動活動的動畫。

func startLoadingAnimator() -> Void { 
    dispatch_async(dispatch_get_main_queue(), ^(){ 
     //Add method, task you want perform on mainQueue 
     //Control UIView, IBOutlet all here 

     UIView.animateWithDuration(0.25, animations: { 
      self.loadingView.alpha = 1 
      self.activityIndicator.startAnimating() 
     }) 
    }) 
    }