4_2网络学习第二天--XML解析

1、XML的数据：

<?xml version="1.0" encoding="utf-8" ?> （表示XML文件版本）

<CityName>北京</CityName> （一个节点，CityName是结点名，北京结点值）

<Item key="1" value="A"></Item>  （key="1"是结点属性，key属性名，“1”属性值）

注意：XML是层次嵌套的结构

2、解析XML：

//开始加载数据
-(void)startDownloadData
{
    NSString *urlSring=[NSString stringWithFormat:MAIN_SHOP_URL,_city,_category,_offset,_pageSize];

    _request=[[LCHttpRequest alloc]init];

    [_request requestUrl:urlSring target:self action:@selector(dealDownloadFinish:)];

}
//加载完成后，解析和处理数据
-(void)dealDownloadFinish:(LCHttpRequest *)request
{
    //解析XML -利用第三方开源库 GDataXMLDocument
    GDataXMLDocument *doc=[[GDataXMLDocument alloc]initWithData:request.data options:0 error:nil];
    NSArray *list=[doc nodesForXPath:@"//promotion" error:nil];
    //利用CDataXMLElement获取
    for (GDataXMLElement * promotion in list) {

        PromotionModel *model=[[PromotionModel alloc]initWithGDataXMLElement:promotion];

        [_allData addObject:model];
    }
}

#import "PromotionModel.h"

@implementation PromotionModel
//封住数据模型-利用获得的GDataXMLElement
-(id)initWithGDataXMLElement:(GDataXMLElement *)element
{
    if (self=[super init]) {
        self.name=[[element elementsForName:@"name"][0] stringValue];
        self.id=[[element elementsForName:@"id"][0] stringValue];
        self.surl=[[element elementsForName:@"surl"][0] stringValue];
        self.wsdimg=[[element elementsForName:@"wsdimg"][0] stringValue];
        self.durl=[[element elementsForName:@"durl"][0] stringValue];
        self.multipagetitle=[[element elementsForName:@"multipagetitle"][0] stringValue];
        self.price=[[element elementsForName:@"price"][0] stringValue];
        self.priceoff=[[element elementsForName:@"priceoff"][0] stringValue];
        self.currentdealcount=[[element elementsForName:@"currentdealcount"][0] stringValue];
        self.starttime=[[element elementsForName:@"starttime"][0] stringValue];
        self.endtime=[[element elementsForName:@"endtime"][0] stringValue];
        self.sevenrefundallowed=[[element elementsForName:@"sevenrefundallowed"][0] stringValue];
        self.expirerefundallowed=[[element elementsForName:@"expirerefundallowed"][0] stringValue];
        self.district=[[element elementsForName:@"district"][0] stringValue];

        self.type2=[[element elementsForName:@"type2"][0] stringValue];
        self.hassub=[[element elementsForName:@"hassub"][0] stringValue];
        self.flag=[[element elementsForName:@"flag"][0] stringValue];

    }
    return self;
}

3、上拉刷新、下拉加载

利用第三方开源库是方便的：例如AH3DPullRefresh：

#pragma mark - 上拉刷新，下拉加载更多
-(void)addPullRefreahAndPullLoadMore
{

    [_tableView setPullToRefreshHandler:^{
        //从第一行数据开始下载
        _offset=1;
        [self startDownloadData];
    }];

    [_tableView setPullToLoadMoreHandler:^{
        _offset+=_pageSize;
        [self startDownloadData];
    }];
}

//上拉或者下拉会调用下面方法
//开始加载数据
-(void)startDownloadData
{
    NSString *urlSring=[NSString stringWithFormat:MAIN_SHOP_URL,_city,_category,_offset,_pageSize];

    _request=[[LCHttpRequest alloc]init];

    [_request requestUrl:urlSring target:self action:@selector(dealDownloadFinish:)];

}
//加载完成后，解析和处理数据
-(void)dealDownloadFinish:(LCHttpRequest *)request
{//解析XML
    GDataXMLDocument *doc=[[GDataXMLDocument alloc]initWithData:request.data options:0 error:nil];
    NSArray *list=[doc nodesForXPath:@"//promotion" error:nil];

    if (_offset==1) {
        NSLog(@"正在刷新数据");
        [_allData removeAllObjects];
    }

    for (GDataXMLElement * promotion in list) {

        PromotionModel *model=[[PromotionModel alloc]initWithGDataXMLElement:promotion];

        [_allData addObject:model];
    }

    //结束刷新
    [_tableView refreshFinished];
    //结束加载更多
    [_tableView loadMoreFinished];

    [_tableView reloadData];
}

4、多使用第三方开源库实现：