1、使用步驟

// 傳入XML數(shù)據(jù)，創(chuàng)建解析器
NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];
// 設(shè)置代理，監(jiān)聽解析過程
parser.delegate = self;
// 開始解析
[parser parse];

2、NSXMLParser解析特點(diǎn)

• NSXMLParser采取的是SAX方式解析，特點(diǎn)是事件驅(qū)動(dòng)，下面情況都會(huì)通知代理
  • 當(dāng)掃描到文檔（Document）的開始與結(jié)束
  • 當(dāng)掃描到元素（Element）的開始與結(jié)束

3、NSXMLParserDelegate代理

• 當(dāng)掃描到文檔的開始時(shí)調(diào)用（開始解析）

- (void)parserDidStartDocument:(NSXMLParser *)parser

• 當(dāng)掃描到文檔的結(jié)束時(shí)調(diào)用（解析完畢）

- (void)parserDidEndDocument:(NSXMLParser *)parser

• 當(dāng)掃描到元素的開始時(shí)調(diào)用（attributeDict存放著元素的屬性）

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict

• 當(dāng)掃描到元素的結(jié)束時(shí)調(diào)用

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName

4、NSXMLParser解析小案例

#import "ViewController.h"
#import <SDWebImage/UIImageView+WebCache.h>
#import <MediaPlayer/MPMoviePlayerViewController.h>
#import "XMGVideo.h"
#import <MJExtension/MJExtension.h>

@interface ViewController ()<NSXMLParserDelegate>
@property (nonatomic, strong) NSMutableArray *videos; /**< 視屏信息 */
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // 只需要在字典轉(zhuǎn)模型之前, 告訴框架要將模型中的哪個(gè)屬性和字典中的哪個(gè)KEY對(duì)應(yīng)
    [XMGVideo setupReplacedKeyFromPropertyName:^NSDictionary *{
        return @{@"ID":@"id"};
    }];

    self.tableView.rowHeight = 150;
    // Do any additional setup after loading the view, typically from a nib.
    NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/video?type=XML"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
//        NSLog(@"%@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);

        // 1.根據(jù)需要解析的XML數(shù)據(jù), 創(chuàng)建NSXMLParser對(duì)象
        NSXMLParser *parser = [[NSXMLParser alloc] initWithData:data];

        // 2.設(shè)置代理, 通過代理方法告訴NSXMLParser, 需要獲取哪些元素和哪些屬性
        parser.delegate = self;

        // 2.開始解析
        [parser parse];
    }];
}
#pragma mark - NSXMLParserDelegate
// 只要開始解析XML文檔就會(huì)調(diào)用
- (void)parserDidStartDocument:(NSXMLParser *)parser
{
    NSLog(@"DidStartDocument");
}
// 只要解析完畢XML文檔就會(huì)調(diào)用
- (void)parserDidEndDocument:(NSXMLParser *)parser
{
     NSLog(@"DidEndDocument");
    // 刷新UI
    [self.tableView reloadData];
}
// 只要開始解析一個(gè)元素就會(huì)調(diào)用
// elementName : 元素名稱
// attributeDict : 元素中的屬性
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    // videos
    // video
//    NSLog(@"%@", elementName);
//    NSLog(@"%@", attributeDict);

    if ([elementName isEqualToString:@"videos"]) {
        return;
    }
    XMGVideo *video = [XMGVideo objectWithKeyValues:attributeDict];
    [self.videos addObject:video];
}

// 只要解析完一個(gè)元素就會(huì)調(diào)用
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
     // video
     // videos
//     NSLog(@"%@", elementName);
}
// 解析出現(xiàn)錯(cuò)誤時(shí)調(diào)用
- (void)parser:(NSXMLParser *)parser validationErrorOccurred:(NSError *)validationError
{
    NSLog(@"error");
}

#pragma mark - datasource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return self.videos.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    // 1.創(chuàng)建cell
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell"];

    // 2.取出對(duì)應(yīng)行的字典
    XMGVideo *video = self.videos[indexPath.row];
    // 2.1設(shè)置數(shù)據(jù)
    cell.textLabel.text = video.name;
    cell.detailTextLabel.text = [NSString stringWithFormat:@"時(shí)長(zhǎng):%@", video.length];
    NSString *urlStr = [NSString stringWithFormat:@"http://120.25.226.186:32812/%@", video.image];
    urlStr = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    [cell.imageView sd_setImageWithURL:[NSURL URLWithString:urlStr] placeholderImage:nil];

    // 3.返回cell
    return cell;
}


- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    // 1.取出選中行對(duì)應(yīng)的字典
    XMGVideo *video = self.videos[indexPath.row];
    // 2.根據(jù)字典中的URL屬性拼接視屏的地址
    NSString *urlStr = [NSString stringWithFormat:@"http://120.25.226.186:32812/%@", video.url];
    urlStr = [urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSURL *url = [NSURL URLWithString:urlStr];
    // 3.播放視屏
    MPMoviePlayerViewController *vc = [[MPMoviePlayerViewController alloc] initWithContentURL:url];
    // 4.顯示控制器
    [self presentViewController:vc animated:YES completion:nil];
}

#pragma mark - lazy
- (NSMutableArray *)videos
{
    if (!_videos) {
        _videos = [NSMutableArray array];
    }
    return _videos;
}
@end