Swift/Xcode - AKPickerView/UIPickerView - 致命錯誤：索引超出範圍

Question

我遇到了問題。我正在使用AKPickerView，它只是一個像UIPickerView一樣工作的cocoapod。

我得到的錯誤是：

fatal error: Index out of range

在這一行： let titleForModel = carModels[item]

這是我和我想實現：

我有兩個pickerViews ，一個用於汽車品牌，另一個用於汽車模型。

他們都有自己的委託和數據源。

直到選擇了汽車牌子/品牌，纔會將carmodelPickerView填充並呈現給用戶。

這是我的全碼：

@IBOutlet weak var manufacterPickView: AKPickerView! 
    @IBOutlet weak var modelPickerView: AKPickerView! 

    var carManufacturers: [String] = ["Select make...", "Abarth","Alfa Romeo","Aston Martin", "Audi", "Bentley","BMW","Bugatti", "Cadillac","Chevrolet","Chrysler","Citroen","Dodge", "Ferrari", "Fiat","Ford","Honda","Hyundai","Jaguar","Jeep","KIA","Lamborghini","Land Rover","Lexus","Lotus","Maserati", "Maybach","Mazda","Mercedes-Benz","Mini", "Mitsubishi","Nissan","Peugeot", "Porsche", "Renault", "Rolls Royce", "SEAT", "Skoda", "Smart","Subaru", "Suzuki", "Toyota", "Vauxhall", "Volkswagen", "Volvo"] 

    var carModels = [" "] 
    var carModelsBackup = [" "] 
    var abarthModelsArray = ["500", "500C", "Grande Punto", "Punto Evo"] 

    var alfaRomeoModelsArray = ["147", "156", "159","4C", "8C", "Brera", "Giulietta", "GT", "Mito"] 


    override func viewDidLoad() { 

     super.viewDidLoad() 

     self.manufacterPickView.dataSource = self 
     self.manufacterPickView.delegate = self 

     self.modelPickerView.dataSource = self 
     self.modelPickerView.delegate = self 

     self.manufacterPickView.font = UIFont(name: "HelveticaNeue-Light", size: 20)! 
     self.manufacterPickView.highlightedFont = UIFont(name: "HelveticaNeue", size: 20)! 
     self.manufacterPickView.pickerViewStyle = .wheel 
     self.manufacterPickView.maskDisabled = false 
     self.manufacterPickView.reloadData() 


     self.modelPickerView.font = UIFont(name: "HelveticaNeue-Light", size: 20)! 
     self.modelPickerView.highlightedFont = UIFont(name: "HelveticaNeue", size: 20)! 
     self.modelPickerView.pickerViewStyle = .wheel 
     self.modelPickerView.maskDisabled = false 
     self.modelPickerView.reloadData() 
    } 


    func numberOfItemsInPickerView(_ pickerView: AKPickerView) -> Int { 

     var carBrand : Int = carManufacturers.count 


     if pickerView == manufacterPickView { 

     return self.carManufacturers.count 
     } 

     if pickerView == modelPickerView { 

      return self.carModels.count 
     } 

     return carBrand 
    } 





    func pickerView(_ pickerView: AKPickerView, titleForItem item: Int) -> String { 

     if pickerView == manufacterPickView { 

      var titleForItem = carManufacturers[item] 

       return titleForItem 
     } 

      if pickerView == modelPickerView { 
       let titleForModel = carModels[item] //This is the line which appears in red and breaks at 
       return titleForModel 
      } 



     return "" 
    } 


    func pickerView(_ pickerView: AKPickerView, didSelectItem item: Int) { 

     if pickerView == manufacterPickView { 

     if carManufacturers[item] == "Abarth" { 
      carModels = abarthModelsArray 
      modelPickerView.reloadData() 
      } 


     else if carManufacturers[item] == "Alfa Romeo" { 
      carModels = alfaRomeoModelsArray 
      modelPickerView.reloadData() 
     } 
     else { 

      carModels = carModelsBackup 
      modelPickerView.reloadData() 
     } 
    } 
     modelPickerView.reloadData() 
    } 

當我選擇一個模型，然後應用程序崩潰切換manufacterPickView。

如果這是一個簡單的問題，我非常抱歉。我從來沒有使用UIPickerView，因此我爲什麼掙扎的原因。有人可以幫我嗎？

謝謝。

Answer 1

看看這是否有幫助，如果它不再告訴我這個問題，我會編輯它！

 var isManufacterSelected: Bool = false 

    func numberOfItemsInPickerView(_ pickerView: AKPickerView) -> Int { 

      if pickerView == manufacterPickView { 

      return self.carManufacturers.count 
      } 

      if pickerView == modelPickerView && isManufacterSelected && !carModels.isEmpty { 

       return self.carModels.count 
      } 
      else { 
       return 0 
      } 
     } 





     func pickerView(_ pickerView: AKPickerView, titleForItem item: Int) -> String { 

      if pickerView == manufacterPickView {   
        return carManufacturers[item] 
      } 

       if pickerView == modelPickerView &&isManufacterSelected { 
        return carModels[item] 
       } 
     } 
     func pickerView(_ pickerView: AKPickerView, didSelectItem item: Int) { 

      if pickerView == manufacterPickView { 

      if carManufacturers[item] == "Abarth" { 
       carModels.removeAll() 
       carModels = abarthModelsArray 
       isManufacterSelected = true 
       modelPickerView.reloadData() 
       } 


      else if carManufacturers[item] == "Alfa Romeo" { 
       carModels.removeAll() 
       carModels = alfaRomeoModelsArray 
       isManufacterSelected = true 
       modelPickerView.reloadData() 
      } 

      else if carManufacturers[item] == "Select make..." { 
       isManufacterSelected = false 
       carModels.removeAll() 
       modelPickerView.reloadData() 
      } 
      else { 
       carModels.removeAll() 
       modelPickerView.reloadData() 
      } 
     } 
    } 

Answer 2

修好了。我注意到一件事。 modelPickerView不會重置。

所以我把這個放在首位。

這行代碼幫助我：

modelPickerView.selectItem(0, animated: true)

我的代碼現在工作並不會崩潰。