下面的逻辑实现了带空格的简单 16 位信用卡格式。
编辑:针对 Swift 4/5 调整代码
第 1 步:为信用卡文本字段创建操作
self.txtFieldCreditCardNumber.addTarget(self, action: #selector(didChangeText(textField:)), for: .editingChanged)
第 2 步:从文本字段的选择器方法中调用一个方法来执行格式化
@objc func didChangeText(textField:UITextField) {
textField.text = self.modifyCreditCardString(creditCardString: textField.text!)
}
步骤3:实现方法“modifyCreditCardString”
func modifyCreditCardString(creditCardString : String) -> String {
let trimmedString = creditCardString.components(separatedBy: .whitespaces).joined()
let arrOfCharacters = Array(trimmedString)
var modifiedCreditCardString = ""
if(arrOfCharacters.count > 0) {
for i in 0...arrOfCharacters.count-1 {
modifiedCreditCardString.append(arrOfCharacters[i])
if((i+1) % 4 == 0 && i+1 != arrOfCharacters.count){
modifiedCreditCardString.append(" ")
}
}
}
return modifiedCreditCardString
}
第四步:实现UITextField的委托,将卡号限制为16个字符。 19 = 16 + 3(每4位数字后1个空格)
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let newLength = (textField.text ?? "").count + string.count - range.length
if(textField == txtFieldCreditCardNumber) {
return newLength <= 19
}
return true
}
希望这会有所帮助。谢谢