仅从其中文本的末尾启用编辑 TextField

Question

我正在为 phone 号码创建一个 TextField。但是我遇到了一些麻烦：我需要阻止用户从任何地方编辑它，而不是从字符串的结尾。

我尝试使用“Touch up Inside”重置插入符，但它似乎对 TextField 禁用。

有什么方法可以限制插入符号的可能位置吗？

问题是它破坏了我的代码，它格式化了 phone 数字。如果您有任何其他好的方法来格式化它而不会出现此问题（我需要字符串看起来完全像这样：+7 (123) 456-78-90，而不是任何其他方法），我将非常感谢您的帮助。

private static var prev_phone: String = ""
@IBAction func phoneFieldTextChanged(_ sender: Any){
    if let phone = phone_field.text{
        if(phone.count <= 4){
            phone_field.text = "+7 ("
        }
        else{
            if phone.count > RegistrationViewController.prev_phone.count{
                if(phone.count == 7){
                    phone_field.text! += ") "
                }
                if(phone.count == 12){
                    phone_field.text! += "-"
                }
                if(phone.count == 15){
                    phone_field.text! += "-"
                }
                if(phone.count > 18){
                    phone_field.text = String(phone.prefix(18))
                }
            }
            if phone.count < RegistrationViewController.prev_phone.count{
                if(phone.count == 8){
                    phone_field.text! = String(phone.prefix(6))
                }
                if(phone.count == 12){
                    phone_field.text! = String(phone.prefix(11))
                }
                if(phone.count == 15){
                    phone_field.text! = String(phone.prefix(14))
                }
                if(phone.count > 18){
                    phone_field.text = String(phone.prefix(18))
                }
            }
        }
    }
    else{
        phone_field.text = "+7 ("
    }
    RegistrationViewController.prev_phone = phone_field.text!
}

Answer 1

在这种情况下，为什么要使用 UITextField ？例如，您可以创建一个自己制作的自定义键盘，只有数字和删除按钮。用户只能键入一个数字或将其删除。将键入的数字添加到格式化字符串由您决定。

Answer 2

将此 class 分配给您的文本字段以防止用户从任何地方对其进行编辑。

class RestrictionTextField: UITextField {

    override func closestPosition(to point: CGPoint) -> UITextPosition? {
        let beginning = self.beginningOfDocument
        let end = self.position(from: beginning, offset: self.text?.count ?? 0)
        return end
    }
    
    override func canPerformAction(_ action: Selector, withSender sender: Any?) -> Bool {
        if action == #selector(UIResponderStandardEditActions.copy(_:)) || action == #selector(UIResponderStandardEditActions.select(_:)) || action == #selector(UIResponderStandardEditActions.cut(_:)) || action == #selector(UIResponderStandardEditActions.paste(_:)) || action == #selector(UIResponderStandardEditActions.selectAll(_:)){
            return false
        }
        else {
            return super.canPerformAction(action, withSender: sender)
        }
    }
}

对于您的文本字段，您可以使用这个简单的解决方案。

let kPhonePattern = "+# (###) ###-##-##"
let kPhonePatternReplaceChar: Character = "#"

extension String {
    var digits: String {
        return String(filter(("0"..."9").contains))
    }
    
    func applyPatternOnNumbers(pattern: String = kPhonePattern, replacmentCharacter: Character = kPhonePatternReplaceChar) -> String {
        var pureNumber = self.replacingOccurrences( of: "[^0-9]", with: "", options: .regularExpression)
        for index in 0 ..< pattern.count {
            guard index < pureNumber.count else { return pureNumber }
            let stringIndex = String.Index(encodedOffset: index)
            let patternCharacter = pattern[stringIndex]
            guard patternCharacter != replacmentCharacter else { continue }
            pureNumber.insert(patternCharacter, at: stringIndex)
        }
        return pureNumber
    }
}

用法：

@IBAction func phoneFieldTextChanged(_ sender: UITextField){
    sender.text = sender.text?.applyPatternOnNumbers()
}

仅从其中文本的末尾启用编辑 TextField

Enable editing TextField only from the end of the text inside it

ios

swift

string

uitextfield

string-formatting