网络：XML 解析

#import "ViewController.h"
#import "CZVideo.h"
@interface ViewController ()<NSXMLParserDelegate>
@property (nonatomic, strong) NSMutableArray *videos;
@property (nonatomic, strong) CZVideo *currentVideo; // 当前解析的模型
@property (nonatomic, strong) NSMutableString *elementString;
@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
// NSURL
NSURL *url = [NSURL URLWithString:@"http://localhost/videos.xml"];
// 创建请求
NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:1 timeoutInterval:15];

// 异步发送请求
[NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc]init] completionHandler:^(NSURLResponse * _Nullable response, NSData * _Nullable data, NSError * _Nullable connectionError) {

NSXMLParser *xml = [[NSXMLParser alloc]initWithData:data];

// 设置代理
xml.delegate = self;

[xml parse];

//        NSLog(@"response = %@ data = %@",response,data);
//        NSLog(@"%@",xml);
}];
}

// 到现在还没有一个好用的第三方
// 做即时通讯 xmpp (xml)
#pragma mark - xml 解析代理
- (void)parserDidStartDocument:(NSXMLParser *)parser {
NSLog(@"1. 开始文档");
// 创建一个可变数组
self.videos = [NSMutableArray array];
}

// 2，3，4 是循环
- (void)parser:(NSXMLParser *)parser didStartElement:(nonnull NSString *)elementName namespaceURI:(nullable NSString *)namespaceURI qualifiedName:(nullable NSString *)qName attributes:(nonnull NSDictionary<NSString *,NSString *> *)attributeDict
{
NSLog(@"2.发现节点%@",elementName);
NSLog(@"节点属性%@",attributeDict);
// 如果是video 创建模型, 并且做成属性保存起来(current)
if ([elementName isEqualToString:@"video"]) {
self.currentVideo = [[CZVideo alloc]init];
}
// 初始化拼接字符串(没有使用懒加载)
//    self.elementString = [NSMutableString string];
// 使用懒加载(清掉string)
[self.elementString setString:@""];
}

// 3. 可能调用多次
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
NSLog(@"3. 发现节点内容 = %@",string);
// 拼接节点内容(可变字符串)
[self.elementString appendString:string];
}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
NSLog(@"4. 结束节点 %@",elementName);
// 其他的就设置模型的属性值
//    if ([elementName isEqualToString:@"name"]) {
//        self.currentVideo.name = self.elementString;
//    }else if ([elementName isEqualToString:@"length"]) {
//        self.currentVideo.length = self.elementString;
//    }else if ([elementName isEqualToString:@"videoURL"]) {
//        self.currentVideo.videoURL = self.elementString;
//    }else if ([elementName isEqualToString:@"imageURL"]) {
//        self.currentVideo.imageURL = self.elementString;
//    }else if ([elementName isEqualToString:@"desc"]) {
//        self.currentVideo.desc = self.elementString;
//    }else if ([elementName isEqualToString:@"teacher"]) {
//        self.currentVideo.teacher = self.elementString;
//    }

if ([elementName isEqualToString:@"video"]) {
// 如果是video 把模型保存到数组
[self.videos addObject:self.currentVideo];
}else if (![elementName isEqualToString:@"videos"]) {
// kvc 设值
[self.currentVideo setValue:self.elementString forKey:elementName];
}

// 妙果是videos 不需要做任务操作
}

- (void)parserDidEndDocument:(NSXMLParser *)parser {
NSLog(@"5. 结束文档");
NSLog(@"%@",self.videos);
}

- (NSMutableString *)elementString {
if (_elementString == nil) {
_elementString = [NSMutableString string];
}
return _elementString;
}

@end

#import <Foundation/Foundation.h>

@interface CZVideo : NSObject
@property (nonatomic, copy) NSString *name;
@property (nonatomic, copy) NSString *length;
@property (nonatomic, copy) NSString *videoURL;
@property (nonatomic, copy) NSString *imageURL;
@property (nonatomic, copy) NSString *desc;
@property (nonatomic, copy) NSString *teacher;

@end

#import "CZVideo.h"

@implementation CZVideo

@end