Json和變量範圍

Question

我的錯誤應該是相當明顯的，但我找不到它;

我一個全局變量初始化我的課的開頭：

class InscriptionStageViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource { 
var lesSemaines = [String]() 

我嘗試使用該功能

func getSemainesStages(){ 
     let url = URL(string: "http://www.boisdelacambre.be/ios/json/semaines.json") 
     let task = URLSession.shared.dataTask(with: url!){ (data, response, error) in 
      if let content = data { 
       do { 
        let myJson = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject 
        let listeSemaines = myJson["semaine"] as! [[String:AnyObject]] 
        //print(listeSemaines) 

        for i in 0...listeSemaines.count-1 { 
         var tabSem = listeSemaines[i] 
         let intituleSemaine:String = tabSem["intitule"] as! String 
         //let dateSemaine:String = tabSem["date"] as! String 

         DispatchQueue.main.sync 
          { 

           self.lesSemaines.append(intituleSemaine) 
          } 

        } 

       } catch 
       { 
        print("erreur Json") 
       } 
      } 

     } 
     task.resume() 
    } 

當我打電話來填充這個數組有一個遙遠的JSON文件我函數在viewDidLoad，然後我打印我的全局數組，它是空的（URL是正確的，json數據被正確讀取，當我讀取循環中數組附加的數據時，它會打印（所需）值。 ）

在此先感謝

Answer 1

下載需要時間。引入另一個梅索德：

func updateUi() { 
    print(lesSemaines) 
    //pickerView.reloadAllComponents() 
} 

而且後稱之爲完成下載：

func getSemainesStages(){ 
    // ... your code 
    let task = URLSession.shared.dataTask(with: url!){ (data, response, error) in 
     // ... your code   
     for tabSem in listeSemaines{ 
      guard let intituleSemaine = tabSem["intitule"] as? String else { 
       print("erreur Json") 
       continue 
      } 
      self.lesSemaines.append(intituleSemaine)  
     } 

     // update UI *after* for loop 
     DispatchQueue.main.async { 
      updateUi() 
     } 
     // ... your code 
    } 
} 

Answer 2

我已將您的代碼更新到Swift 3.請用下面的代碼替換它。

func getSemainesStages(){ 
    let url = URL(string: "http://www.boisdelacambre.be/ios/json/semaines.json") 
    let task = URLSession.shared.dataTask(with: url!){ (data, response, error) in 
     if let content = data { 
      do { 
       let myJson = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as! [String: Any] 
       let listeSemaines = myJson["semaine"] as! [[String: Any]] 

       for i in 0...listeSemaines.count-1 { 
        var tabSem = listeSemaines[i] 
        let intituleSemaine:String = tabSem["intitule"] as! String 
        self.lesSemaines.append(intituleSemaine) 
       } 
       print(self.lesSemaines) 
      } catch { 
       print("erreur Json") 
      } 
     } 

    } 
    task.resume() 
}