Swift TextField 限制长度

 

 

1.遵循代理    

UITextFieldDelegate

 

2.设置代理

 

 textf.delegate = self

 

3.实现代理

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

        let text = textField.text!

        let len = text.characters.count + string.count - range.length

        return len<=6

    }