方法更新巨大的延迟后的用户界面

我有一个UIView作为父母和UIActivityIndicator作为子视图。每当用户提交凭证，我开始活动动画，并在方法名称startLoadingAnimator()中分配父视图alpha = 1.0它之后它调用一个API，当API完成调用时，我设置为通过停止它并设置在名为stopLoadingAnimator()的方法中父视图的alpha = 0.0。问题是stopLoadingAnimator()在其时间调用完美，但屏幕上的效果显示延迟后它应该就像方法运行时它应该消失在那个瞬间，但它需要很长时间消失。方法更新巨大的延迟后的用户界面

停止活动动画。

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

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



}

启动活动的动画。

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() 
    }

来源

2016-09-15 Ahsan Imtiaz

切勿从后台线程更新UI。 – rmaddy

是的，更新主线程上的UI。 – Santosh

我想在完成API回调后立即更新UI。与Objective-C类似，我们更新完成块中的UI –

更新您的启动和停止动画的方法，所以他们总是在主线程像这样上执行：

停止活动动画。

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() 
     }) 
    }) 
}

启动活动的动画。

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() 
     }) 
    }) 
    }

来源

2016-09-15 16:04:06

方法更新巨大的延迟后的用户界面

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