#12瘋狂購物 App — UIStepper 和數字變字串練習

利用UIStepper及數字轉換成文字

1.先宣告各個物件的變數

@IBOutlet weak var bananaImage: UIImageView!
@IBOutlet weak var mangoImage: UIImageView!
@IBOutlet weak var pineappleImage: UIImageView!
@IBOutlet weak var strawbarryImage: UIImageView!
@IBOutlet weak var fruitImage: UIImageView!

@IBOutlet weak var bananaStepper: UIStepper!
@IBOutlet weak var mangoStepper: UIStepper!
@IBOutlet weak var pineappleStepper: UIStepper!
@IBOutlet weak var strawbarryStepper: UIStepper!
@IBOutlet weak var totalView: UIView!
@IBOutlet weak var totalMoneyLabel: UILabel!
@IBOutlet weak var bananaQtyLabel: UILabel!
@IBOutlet weak var mangoQtyLabel: UILabel!
@IBOutlet weak var pineappleQtyLabel: UILabel!
@IBOutlet weak var strawbarryQtyLabel: UILabel!
var bananaQty:Int = 0
var mangoQty:Int = 0
var pineappleQty:Int = 0
var strawbarryQty:Int = 0
//水果價錢
var bananaMoney:Int = 100
var mangoMoney:Int = 150
var pineappleMoney:Int = 120
var strawbarryMoney:Int = 250
var totalMoney:Int = 0

//NumberFormatter 可以幫我們將數字變成特定的字串格式。
let formatter = NumberFormatter()

2. 在viewdidload( )裡面設定圖片的圓角

fruitImage.layer.cornerRadius = 20        bananaImage.layer.cornerRadius = 20        mangoImage.layer.cornerRadius = 20        pineappleImage.layer.cornerRadius = 20        strawbarryImage.layer.cornerRadius = 20        totalView.layer.cornerRadius = 20    

3.把四個UIStepper都拉到同一個function，同步變更數量及總金額

//把Stepper字串轉成Int        
bananaQty = Int(bananaStepper.value)        
mangoQty = Int(mangoStepper.value)        
pineappleQty = Int(pineappleStepper.value)        
strawbarryQty = Int(strawbarryStepper.value)    
//把數字轉換成字串寫到Label
bananaQtyLabel.text = " \(bananaQty)"        
mangoQtyLabel.text = " \(mangoQty)"        
pineappleQtyLabel.text = " \(pineappleQty)"        strawbarryQtyLabel.text = " \(strawbarryQty)"  
//計算總金額
totalMoney = (bananaQty * bananaMoney) + (mangoQty * mangoMoney) + (pineappleQty * pineappleMoney) + (strawbarryQty * strawbarryMoney) 
//把小數點去掉
formatter.maximumFractionDigits = 0
//轉換成錢幣符號   
formatter.numberStyle = .currency
totalMoneyLabel.text = formatter.string(from: NSNumber(value: totalMoney))    
    
//將數字以指定的格式轉成字串，由於 string(from:) 的參數 from 型別是 NSNumber，所以我們須以 NSNumber(value: money) 將 Int 型別的 money 變成 NSNumber。 
       
//totalMoneyLabel.text = " \(totalMoney)" 只顯示數字