Swift：如果用户达到最大字符，如何移动到下一个 UITextField

Question

I'm trying to find a way that when the user reach to the maximum characters the text field move to next.

Here is my code:

extension ViewController: UITextFieldDelegate {
    
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        
        guard let text = textField.text else {
            return true
        }
        let length = text.count + string.count - range.length
        let max = 2
        
        if textField == weTextField {
            return length <= max
        }
        else if textField == theyTextField {
            return length <= max
        }
        
        return true
    }
    
}

Thanks

Answer 1

You can achieve that by doing something like this:

1. create a function that will change your first responder when a character limit is reached

    @objc func valueDidChange(_ textField: UITextField) { guard let text = textField.text else { return } let maxLength = 2 switch textField { case textField1 where text.count == maxLength: textField2.becomeFirstResponder() case textField2 where text.count == maxLength: textField3.becomeFirstResponder() default: break } }

2. Add that function to your textfield so it's triggered when the textfield is edited. In the above case, I added it to both textField1 and textField2

    textField1.addTarget(self, action: #selector(valueDidChange), for: .editingChanged) textField2.addTarget(self, action: #selector(valueDidChange), for: .editingChanged)