TBXML库的用法

-(id)initWithMgzListXML:(NSString *)xmlString{    self = [super init];    if(self){        self.contentArray = [[NSMutableDictionary alloc] init];        NSString *xml = xmlString;        xml =[xml stringByReplacingOccurrencesOfString:@"&" withString:@"&"];        xml =[xml stringByReplacingOccurrencesOfString:@"'" withString:@"'"];        xml =[xml stringByReplacingOccurrencesOfString:@"<" withString:@"<"];        xml =[xml stringByReplacingOccurrencesOfString:@">" withString:@">"];        xml =[xml stringByReplacingOccurrencesOfString:@""" withString:@"\""];        NSLog(@"xml is ------------>%@",xml);        mainXMLSource = [[TBXML alloc] initWithXMLString:xml];        TBXMLElement *root = mainXMLSource.rootXMLElement;        if(root){            TBXMLElement *contents = [TBXML childElementNamed:@"MagazineList" parentElement:root];            if(contents){                TBXMLElement *content = [TBXML childElementNamed:@"Magazine" parentElement:contents];                NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];                  while(content){                    //解析属性                    NSString *idStr = [NSString stringWithString:[TBXML valueOfAttributeNamed:@"Id" forElement:content]];                    NSString *titleStr = [TBXML valueOfAttributeNamed:@"Title" forElement:content];                    NSString *subTitleStr = [TBXML valueOfAttributeNamed:@"Subtitle" forElement:content];                    NSString *categoryIdStr = [TBXML valueOfAttributeNamed:@"CategoryId" forElement:content];                    NSString *categoryNameStr = [TBXML valueOfAttributeNamed:@"CategoryName" forElement:content];                     [dict setObject:idStr forKey:@"Id"];                     [dict setObject:titleStr forKey:@"Title"];                     [dict setObject:subTitleStr forKey:@"Subtitle"];                     [dict setObject:categoryIdStr forKey:@"CategoryId"];                     [dict setObject:categoryNameStr forKey:@"CategoryName"];                    //解析元素代码                    TBXMLElement *description =  [TBXML childElementNamed:@"Description" parentElement:content];                    if(description){                        NSString *str = [TBXML textForElement:description];                        [dict setObject:str forKey:@"Description"];                    }                    TBXMLElement *modifyDate = [TBXML childElementNamed:@"ModifyDate" parentElement:content];                    if(modifyDate){                        NSString *str = [TBXML textForElement:modifyDate];                        [dict setObject:str forKey:@"ModifyDate"];                    }                                        NSMutableArray *list = [self.contentArray objectForKey:categoryIdStr];                    if(list == nil || [list count]==0){                        list = [NSMutableArray arrayWithCapacity:1];                    }                    [list addObject:dict];                    [self.contentArray setObject:list forKey:categoryIdStr];                    //给下一个元素赋值，配合WHILE循环使用                    content = [TBXML nextSiblingNamed:@"Magazine" searchFromElement:contents];                }                //            }        }            }    return self;}