在UISearchBar textDidChange委托中搜索bar对象nil

Question

我遇到了UISearchBar的textDidChange委托方法的一个非常奇怪的行为。这是我的代码

cdr

我在委托方法中为searchBar做了一个po，我收到了以下消息

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText
{

    searchText = [searchText stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
    if (![searchText isEqualToString:@""]) {

        [self searchedWithText:searchText]; // I am using this method to fetch my search results from coredata

        [searchBar becomeFirstResponder]; // For making the search field active
    }

}

-(void)searchedWithText:(NSString *)searchText {

    // In this method the type of searchText is shown as NSTaggedPointerString and the value is nil

}

我的问题是searchWithText方法中的searchText参数是nil。所以coredata的结果是零。我在这做错了什么？提前致谢