为什么我需要按此按钮两次才能显示数据？

Question

我不明白为什么我需要按两次按钮才能让标签填充收集到的数据。我不确定我的 json 解析是否有问题，或者是否存在某种范围问题。我确定这里有多余的代码，但我正在尝试所有我能想到的并通过谷歌找到的东西。

import UIKit

struct SkillStats {
var Rank, Level, Experience: String
init(Rank: String = "", Level: String = "", Experience: String = "") {
    self.Rank = Rank
    self.Level = Level
    self.Experience = Experience
    }
}

var rsn: String = ""

class ViewController: UIViewController {
  var Total = SkillStats()

@IBOutlet weak var totalXP: UILabel!
@IBOutlet weak var totalLevel: UILabel!
@IBOutlet weak var totalRank: UILabel!

@IBOutlet weak var getrsn: UITextField!
@IBAction func rsnButton(_ sender: Any) {
rsn = getrsn.text!

rsn = rsn.replacingOccurrences(of: " ", with: "%20")
rsn = rsn.replacingOccurrences(of: "-", with: "%2D")

print(rsn)

//let rsn = "Real%20Nice"
 let jsonUrlString = "http://services.runescape.com/m=hiscore_oldschool/index_lite.ws?player=" + rsn
 guard let url = URL(string: jsonUrlString) else
 {return}

 URLSession.shared.dataTask(with: url) { (data, repsonse, err) in

 guard let data = data else {return}

 let dataAsString = String(data: data, encoding: .utf8)
 //print(dataAsString)

 let result = dataAsString?.components(separatedBy: [",","\n"])

 //comment this block
 //Total.Rank = result![0]
 //Total.Level = result![1]
 //Total.Experience = result![2]


  self.Total = SkillStats(Rank: result![0], Level: result![1], Experience: result![2])

 //printing stats to console
  print("Total Rank: " + self.Total.Rank)
  print("Total Level: " + self.Total.Level)
  print("Total Experience: " + self.Total.Experience)
 }.resume()

totalRank.text = "Rank: " + Total.Rank
totalLevel.text = "Level: " + Total.Level
totalXP.text = "XP: " + Total.Experience
}

Answer 1

按下按钮并等待新的几秒钟，因为您正在进行 api 调用，这将需要一些时间来从服务器获取数据并更新您的标签文本。

更新

要在几秒钟后更新您的标签，您可以执行以下操作：

DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {

            self.totalRank.text = "Rank: " + self.Total.Rank
            self.totalLevel.text = "Level: " + self.self.Total.Level
            self.totalXP.text = "XP: " + self.Total.Experience
        }

PS - 是的，您可以像上面的代码一样传递小于 1 的第二个值。