UITextField 의 text 가 영인지 체크하는 방법

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

    NSRange textFieldRange = NSMakeRange(0, [textField.text length]);

    if (NSEqualRanges(range, textFieldRange) && [string length] == 0) {

        [_keywordClearButton setHidden:YES];

    } else

        [_keywordClearButton setHidden:NO];

    

    return YES;

}