Question

我正在尝试在文本字段的开头添加$符号。如果字符数为1，则$ sign不会被隐藏，但如果字符数为零，则隐藏$符号并显示占位符文本。我有代码，但它无法正常工作。它不会显示$符号。你能帮我么。这是下面的代码。

override func viewDidLoad() {
    super.viewDidLoad()

    self.Price.delegate = self



    didChangeText()
}

var amount: String {
    get {
        if self._amount.characters.count > 1 {
            return (self._amount as NSString).substring(from: 2)
        }
        return ""
    }
}

// MARK: - UITextField Observing


private var newVal: String = ""
private var _amount: String = ""

func didChangeText() {
    if ((Price.text?.characters.count)! > 2) {
        if Price.text?.range(of: "$ ") == nil {
            Price.text = newVal
        }
    }

    if ((Price.text?.characters.count)! == 1) && ((Price.text?.characters.count)! > newVal.characters.count) {
        Price.text = "$ " + Price.text!
    }
    if ((Price.text?.characters.count)! == 2) && ((Price.text?.characters.count)! < newVal.characters.count) {
        Price.text = ""
    }
    newVal = Price.text ?? ""
    _amount = newVal
}

Answer 1

请尝试以下操作：

let priceField = UITextField(frame: CGRect(x: 0.0, y: 0.0, width: 100.0, height: 30.0))
let leftDollarSymbol = UILabel(frame: CGRect(x: 0.0, y: 0.0, width: 15.0, height: 30.0))
leftDollarSymbol.textAlignment = .center
leftDollarSymbol.text = "$"
priceField.leftView = leftDollarSymbol

根据您的需要更新leftDollarSymbol或设置leftview nil

文本字段的前缀不起作用

1 个答案: