创建具有有限数字和小数位数的自定义UITextField

import UIKit

class CustomTextField: UITextField, UITextFieldDelegate {
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.delegate = self
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        self.delegate = self
    }
    
    override func awakeFromNib() {
        super.awakeFromNib()
        self.delegate = self
    }
    
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        // 限制只能输入数字和小数点
        let allowedCharacters = CharacterSet(charactersIn: "0123456789.")
        let characterSet = CharacterSet(charactersIn: string)
        if !allowedCharacters.isSuperset(of: characterSet) {
            return false
        }
        
        // 限制小数位数为两位
        let currentText = textField.text ?? ""
        let newText = (currentText as NSString).replacingCharacters(in: range, with: string)
        let decimalSeparator = Locale.current.decimalSeparator ?? "."
        let components = newText.components(separatedBy: decimalSeparator)
        if components.count > 2 {
            return false
        }
        if components.count == 2 && components[1].count > 2 {
            return false
        }
        
        return true
    }
}

let customTextField = CustomTextField(frame: CGRect(x: 0, y: 0, width: 200, height: 40))
customTextField.placeholder = "请输入数字"