使用`textField：shouldChangeCharactersInRange：`，我如何发现字符不匹配？

Question

I'm using the code below for setting validation of textfield as it should not enter above 15 character length .

 let limitLength = 15

 func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {

    // set maximum length for password and confirm password
    if textField == txtPassword { // if textfield password is editing

        guard let text = textField.text else { return true }
        let newLength = text.characters.count + string.characters.count - range.length
        return newLength <= limitLength

    } else if textField == txtConfirmpassword { // if textfield confirm password is editing
        guard let text = textField.text else { return true }
        let newLength = text.characters.count + string.characters.count - range.length
        return newLength <= limitLength
    }
    return true
}

there are two textfield as password and confirm password i want to check validation whether they have same string or not?

"textField:shouldChangeCharactersInRange" is method we need to use but i don't know how to compare while user is entering and i need to display alert message that they are not same Note :- it should not compare while click on any button.

Answer 1

try like this

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {

// set maximum length for password and confirm password
if textField == txtPassword { // if textfield password is editing

    guard let text = textField.text else { return true }
    let newLength = text.characters.count + string.characters.count
    return newLength <= limitLength

} else if textField == txtConfirmpassword { // if textfield confirm password is editing
    guard let text = textField.text else { return true }
    let newLength = text.characters.count + string.characters.count
    if newLength <= limitLength && txtPassword.text.hasPrefix("\(text)\(string)") {
    return true
} else {
   // here u can show alert
     textField.resignFirstResponder()
     return false
 }
      }
        return true
   }