UITextField

## 글자수 입력 제한

Ex) 4자까지만 입력가능]

#pragma mark - UITextFieldDelegate
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    NSString *newString = [textField.text stringByReplacingCharactersInRange:range
                                                                  withString:string];
    int length = [newString length] ;
    if (length >= 4) {
        textField.text = [newString substringToIndex:4];
        return NO;
    }
    return YES;
}

 

## 포커스 이동 

[textField becomeFirstResponder];