iOS UITextField限制输入长度

#pragma mark - 限制输入长度

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

{

    if (textField == self.textField) {

        if (string.length == 0) return YES;

        

        NSInteger existedLength = textField.text.length;

        NSInteger selectedLength = range.length;

        NSInteger replaceLength = string.length;

        

        if (existedLength - selectedLength + replaceLength > 11) {

            return NO;

        }

    }

    

    return YES;

}