如何在Swift中使用NSUserDefault和PickerView？

Question

我做了一些Labels，使用PickerView更改。但是，当我更改Label并且如果我再次运行我的应用程序，它不会保存到选定的一个。所以我必须使用NSUserDefault，但我不知道如何正确使用它。

这是我的代码：

var selectedFood = 0 

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource { 

@IBOutlet var foodLabel: UILabel! 
@IBOutlet var labelTwo: UILabel! 
@IBOutlet var labelThree: UILabel! 

@IBOutlet weak var foodPicker: UIPickerView! 

var food = ["Bread", "Pizza", "Pasta", "Hot Dog", "Burger"] 

@IBAction func submitLanguageButton(sender: AnyObject) { 
    if (selectedFood == 0) { 
     foodLabel.text = "Bread" 
     labelTwo.text = "Bread is a staple food prepared from a dough of flour and water..." 
     labelThree.text = "Bread is one of the oldest prepared foods..." // I used random information just as sample   
    } 
    else if (selectedFood == 1) { 
     foodLabel.text = "Pizza" 
     labelTwo.text = "Here will be more informations about Pizza" 
     labelThree.text = "A fact about Pizza" // I used random information just as sample    
    } 
    else if (selectedFood == 2) { 
     foodLabel.text = "Pasta" 
     labelTwo.text = "Here will be more informations about Pasta" 
     labelThree.text = "A fact about Pasta" // I used random information just as sample     
    } 
    else if (selectedFood == 3) { 
     foodLabel.text = "Hot Dog" 
     labelTwo.text = "Here will be more informations about Hot Dog" 
     labelThree.text = "A fact about Hot Dog" // I used random information just as sample     
    } 
    else if (selectedFood == 4) { 
     foodLabel.text = "Burger" 
     labelTwo.text = "Here will be more informations about Burger" 
     labelThree.text = "A fact about Burger" // I used random information just as sample   
    } 
} 

override func viewDidLoad() { 
    super.viewDidLoad() 
    // Do any additional setup after loading the view. 

    foodPicker.delegate = self 
    foodPicker.dataSource = self 


    if (selectedFood == 0) { 
     foodLabel.text = "Bread" 
     labelTwo.text = "Bread is a staple food prepared from a dough of flour and water..." 
     labelThree.text = "Bread is one of the oldest prepared foods..." // I used random information just as sample   
    } 
    else if (selectedFood == 1) { 
     foodLabel.text = "Pizza" 
     labelTwo.text = "Here will be more informations about Pizza" 
     labelThree.text = "A fact about Pizza" // I used random information just as sample    
    } 
    else if (selectedFood == 2) { 
     foodLabel.text = "Pasta" 
     labelTwo.text = "Here will be more informations about Pasta" 
     labelThree.text = "A fact about Pasta" // I used random information just as sample     
    } 
    else if (selectedFood == 3) { 
     foodLabel.text = "Hot Dog" 
     labelTwo.text = "Here will be more informations about Hot Dog" 
     labelThree.text = "A fact about Hot Dog" // I used random information just as sample     
    } 
    else if (selectedFood == 4) { 
     foodLabel.text = "Burger" 
     labelTwo.text = "Here will be more informations about Burger" 
     labelThree.text = "A fact about Burger" // I used random information just as sample   
    } 
} 


func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? { 
    return food[row] 
} 

func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int { 
    return food.count 
} 

public func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int { 
    return 1 
} 

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) { 

    selectedFood = row 
} 

} 

所以，当我选择比萨，每当我跑我的应用我想它比萨，如果我选择另一个例如面食，我想成为那个意大利面。 你能帮我吗？

Answer 1

WBMDDrugManagerErrorCodeSave像这样的选择：

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) { 
    NSUserDefaults.standardUserDefaults().setInteger(row, forKey: "choosenFood") 
    NSUserDefaults.standardUserDefaults().synchronize() 
    self.setLabelsForChoice(row) 
} 

检索像这样选择的选择：

override func viewWillAppear() { 
    super.viewWillAppear() 
    if let previousSelection:Int = NSUserDefaults.standardUserDefaults().integerForKey("choosenFood") as? Int{ 
     self.setLabelsForChoice(previousSelection) 
    } 
} 

创建一个类似的标签更新方法：

func setLabelsForChoice(_choice:Int){ 
    switch _choice{ 
     case 0: 
      foodLabel.text = "Bread" 
      labelTwo.text = "Bread is a staple food prepared from a dough of flour and water..." 
      labelThree.text = "Bread is one of the oldest prepared foods..." 
      break 
     case 1: 
      foodLabel.text = "Pizza" 
      labelTwo.text = "Here will be more informations about Pizza" 
      labelThree.text = "A fact about Pizza" 
      break 
     default: 

      break 
    } 




}