swift - Xcode Swift 赚大钱

Question

我有这段代码可以打印出一笔钱，但有时如果金额是 10 美分的倍数，比如 22.50 美元或 189.20 美元，用户界面会砍掉最后的 0 以显示 22.5 美元或 189.2 美元？

@IBAction func btnCalPress(sender: AnyObject) {
    let tipPer = Double(PercentTip.text!)! / 100
    let billAmt = Double(BillAmount.text!)
    let salesTax = Double(SalesTax.text!)! / 100

    let tipAmt = Double(billAmt! * tipPer)
    let taxAmt = Double(billAmt! * salesTax)
    let totalAmt = tipAmt + taxAmt + billAmt!

    let tipAmountFormat = round(tipAmt * 100) / 100
    let taxAmountFormat = round(taxAmt * 100) / 100
    let totalPayFormat = round(totalAmt * 100) / 100

    TipAmount.text = "Tip: $\(tipAmountFormat)"
    TaxAmount.text = "Tax: $\(taxAmountFormat)"
    TotalAmount.text = "Total: $\(totalPayFormat)"
}

Answer 1

在处理货币时，更容易依赖 NSNumberFormatter，它恰好也处理一些货币的特殊性。

应用于您的代码将是:

@IBAction func btnCalPress(sender: AnyObject) {
    let tipPer = Double(PercentTip.text!)! / 100
    let billAmt = Double(BillAmount.text!)!
    let salesTax = Double(SalesTax.text!)! / 100

    let tipAmt = Double(billAmt * tipPer)
    let taxAmt = Double(billAmt * salesTax)
    let totalAmt = tipAmt + taxAmt + billAmt

    let formatter = NSNumberFormatter()
    formatter.numberStyle = .CurrencyStyle

    let tipAmount = formatter.stringFromNumber(tipAmt)!
    let taxAmount = formatter.stringFromNumber(taxAmt)!
    let totalAmount = formatter.stringFromNumber(totalAmt)!

    TipAmount.text = "Tip: \(tipAmount)"
    TaxAmount.text = "Tax: \(taxAmount)"
    TotalAmount.text = "Total: \(totalAmount)"
}