重构

• 定义 VideoXMLParser 类专门负责 XML 解析
• 将 XML 解析相关代码移动至 VideoXMLParser 中
• 定义类方法

///  解析 Video XML 数据
///
///  @param parser   XML 解析器
///  @param finished 完成回调
+ (void)parserVideo:(NSXMLParser *)parser finished:(void (^)(NSArray *dataList))finished;

• 方法实现

+ (void)parserVideo:(NSXMLParser *)parser finished:(void (^)(NSArray *))finished {
    VideoXMLParser *obj = [[self alloc] init];

    obj.finishedBlock = finished;
    parser.delegate = obj;
    [parser parse];
}

• 方法调用

- (void)loadData {
    NSURL *url = [NSURL URLWithString:@"http://localhost/videos.xml"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:15.0];

    [NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc] init] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {

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

        [VideoXMLParser parserVideo:parser finished:^(NSArray *dataList) {
            self.dataList = dataList;
        }];
    }];
}