Question

我已经为此工作了三天。我正在尝试格式化UITextField中的文本以输出货币格式并保持对齐。我可以将变量中的文本格式化为输出货币，但不在textView中输出，并且NSTextAlignment一直给我一个错误。

import Foundation
import UIKit

class dollarFieldDelegate: NSObject, UITextFieldDelegate {
var currentString = ""
var newCurrency = ""
var newText: NSString = ""

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    newText = textField.text
    textField.NSRightTextAlignment//Tried this several different ways, keep getting 'UITextField does not have member NSRightTextAlignment
    let convertToANumber = string.toInt() //check the replacment string for a Int.
    UIText
    // If string does not contain an Int, stringByReplacingCharactersInRange is not executed
    if convertToANumber != nil {

        currentString += string
        formatCurrency(string: currentString)
        newText = newText.stringByReplacingCharactersInRange(range, withString: newCurrency)
        println("in newText")
        println(newText)
        return true
    }
    else {
       return false}//returns false if checkToSeeIfItsANumber is nil
}
func formatCurrency(#string: String) ->NSString{
    //println("format \(string)")
    let formatter = NSNumberFormatter()
    formatter.numberStyle = NSNumberFormatterStyle.CurrencyStyle
    //formatter.locale = NSLocale(localeIdentifier: "en_US")
    formatter.currencySymbol = "$"
    var numberFromField = (NSString(string: currentString).doubleValue)/100
    newText = formatter.stringFromNumber(numberFromField)!
    //println(newCurrency)
    return newCurrency
}

}

textField中的输出也是1234，但调试器中的输出是$ 1234.56

谢谢！

Answer 1

在viewDidLoad中尝试这一行，它能解决所有问题吗？

textField.delegate = self

Answer 2

所以我明白了。然后，我下载了解决方案。但是，我不明白为什么会这样。为什么返回false（在转换textField之后）给出正确的解决方案？

 func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
    newText = textField.text
    let convertToANumber = string.toInt() //check the replacment string for a Int.
    // If string does not contain an Int, stringByReplacingCharactersInRange is not executed
    if convertToANumber != nil {
        currentString += string
        formatCurrency(string: currentString)
        newText = newText.stringByReplacingCharactersInRange(range, withString: newCurrency)

        textField.text = newText as String
        return false//sends correctly formatted $123.45 to viewController
    }
    else {
       return false}//returns false if checkToSeeIfItsANumber is nil

使用新字符串格式化UITextField中的文本以进行正确对齐和货币？

2 个答案: