JSON&XML

JSON（NSData） --> OC对象

• { } --> NSDictionary@{}
• [ ] --> NSArray@[]
• ""--> NSString@""
• 10--> NSNumber @10
• true --> NSNumber @1

JSON（NSData） --> OC对象

NSJSONReadingMutableContainers = (1UL << 0),//创建出来的数组和字典是可变的
NSJSONReadingMutableLeaves = (1UL << 1),//数组和字典里里面的字符串是可变的
NSJSONReadingAllowFragments = (1UL << 2)//允许解析出来的对象不是字典或者数组

NSDictionary * dict = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];

OC对象 --> SON（NSData)

NSData * data1 = [NSJSONSerialization dataWithJSONObject:@{@"name":@"jake"} options:NSJSONWritingPrettyPrinted error:nil];

利用苹果自带的API播放视频

NSDictionary * dict = self.videos[indexPath.row];
    
    NSString * url = [@"http://120.25.226.186:32812" stringByAppendingPathComponent:dict[@"url"]];
    
    //创建视频播放器
    
    MPMoviePlayerViewController * movie = [[MPMoviePlayerViewController alloc]initWithContentURL:[NSURL URLWithString:url]];
    
//    [self presentViewController:movie animated:YES completion:nil];
    [self presentMoviePlayerViewControllerAnimated:movie];

XML的解析方式

• SAX
  • 大小文件都可以
  • NSXMLParser
• DOM
  • 最后是小文件
  • GdataXML

NSXMLParser的用法

• 创建解析器开始解析

//解析XML数据
//1.创建XML解析器
NSXMLParser * parser = [[NSXMLParser alloc]initWithData:data];

//设置代理
parser.delegate = self;

//2.开始解析
[parser parse];

• 代理遵守协议 实现代理方法

//解析到某个元素
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    if ([elementName isEqualToString:@"videos"]) return;
    
    //第一种方案
//    Video * v = [[Video alloc]init];
//    
//    v.keyValues = attributeDict;
    
    //第二种方案
    Video * v = [Video objectWithKeyValues:attributeDict];
    
    [self.videos addObject:v];
    
}

//某个元素解析完毕
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
    
}

//开始解析文档
- (void)parserDidStartDocument:(NSXMLParser *)parser
{
    
}
//解析完毕
- (void)parserDidEndDocument:(NSXMLParser *)parser
{
    
}

GdataXML

• 设置非ARC标记

Snip20150713_335.png

Snip20150713_336.png

Snip20150713_340.png

• 具体操作

//加载整个文档
GDataXMLDocument *doc = [[GDataXMLDocument alloc] initWithData:data options:0 error:nil];
//获得根节点
doc.rootElement
//获得其他节点
[element elementsForName:@"video"].stringValue
//获得节点的属性
[ele attributeForName:@"name"]

• 实例代码

 // 加载整个文档
GDataXMLDocument *doc = [[GDataXMLDocument alloc] initWithData:data options:0 error:nil];
        
        // 获得所有video元素
        NSArray *elements = [doc.rootElement elementsForName:@"video"];
        for (GDataXMLElement *ele in elements) {
            XMGVideo *video = [[XMGVideo alloc] init];
            video.name = [ele attributeForName:@"name"].stringValue;
            video.url = [ele attributeForName:@"url"].stringValue;
            video.image = [ele attributeForName:@"image"].stringValue;
            video.length = [ele attributeForName:@"length"].stringValue.integerValue;
            
            [self.videos addObject:video];
        }