#pragma mark - NSURLConnection异步下载
-(void)testNSURLConnectionAsyncDownloadData
{
    NSString *urlString = @"http://iappfree.candou.com:8080/free/applications/limited?currency=rmb&page=1&category_id=";
    
    //初始化
    _data = [[NSMutableData alloc] init];
    //发起了一个异步的URL连接请求
    //异步:   执行了方法之后开始下载,立即返回
    //              下载过程在后台(多线程)执行
    _connection = [[NSURLConnection alloc] initWithRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:urlString]] delegate:self startImmediately:YES];
    NSLog(@"initWithRequest 执行完成");
    
}
//代理方法: 接收到服务器响应执行
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    NSLog(@"接收到服务器响应执行");
}
//代理方法: 接收到数据的时候执行
//注意: 当数据比较大, 可能多次执行
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    
    [_data appendData:data];
}
//代理方法: 数据下载完成了
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    //NSString *str = [[NSString alloc] initWithData:_data encoding:NSUTF8StringEncoding];
    //NSLog(@"str = %@",str);
    
    //最简单: 显示所有应用名字
    //解析JSON
    //作用: JSON数据转化为NSArray或NSDictionary
    NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:_data options:NSJSONReadingMutableContainers error:nil];
    //NSLog(@"dict = %@",dict);
    
    //NSArray *appList = dict[@"applications"];
    NSArray *appList = [dict valueForKey:@"applications"];
    for (NSDictionary *appDict in appList) {
        NSLog(@"name = %@",appDict[@"name"]);
    }
    
    
    
    //NSArray *a = @[@"test",@"vec"];
    //NSDictionary *d = @{@"k1":@"v1",@"k2":@"v2"};
    //NSLog(@"v = %@",d[@"k1"]);
    
    
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"error = %@",error);
}


#pragma mark - NSURLConnection同步下载
-(void)testNSURLConnectionSyncDownloadData
{
    NSString *urlString = @"http://iappfree.candou.com:8080/free/applications/limited?currency=rmb&page=1&category_id=";
    
    //发送同步URL请求
    //NSURLRequest URL请求对象
    NSURL *url = [NSURL URLWithString:urlString];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    NSError *error = nil;
    NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:&error];
    if(error == nil)
    {
        NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
        NSLog(@"str = %@",str);
    }
    else
    {
        NSLog(@"下载失败");
    }
    
}
#pragma mark - NSString同步下载
-(void)testNSStringDownloadData
{
    // HTTP中使用URL地址
    //  http:// 地址使用协议(ftp://)
    //  iappfree.candou.com  主机地址(域名和IP)
    //  :8080                   主机端口
    //  /free/applications/limited  网页程序文件路径
    //  ?currency=rmb&page=1&category_id= 程序参数(参数用&分割)
    
    NSString *urlString = @"http://iappfree.candou.com:8080/free/applications/limited?currency=rmb&page=1&category_id=";
    
    //下载数据
    //通过地址生成NSURL对象
    NSError *error = nil;
    NSURL *url = [NSURL URLWithString:urlString];
    NSString *content = [[NSString alloc] initWithContentsOfURL:url encoding:NSUTF8StringEncoding error:&error];
    if (error==nil) {
        NSLog(@"content = %@",content);
    }
    else
    {
        NSLog(@"下载失败");
    }
    
    //项目中怎么使用
    //1.同步形式下载, initWithContentsOfURL下载完了之后才会返回
    //      造成界面假死,不能用
    //2.使用异步下载(NSURLConnection异步下载)
    
}

//JSON
    //JavaScript Object Notation
    
    /*
    {
        "count":20,
        "data":[
            "zhangsan",
            "lisi",
            "wangwu"
        ]
    }
    */
    //[]    表示数组,对应NSArray
    //,     表示并列的数据
    //{}    表示字典,对应NSDictionary
    //:     表示键值对
    //"ta"  表示字符串,对应NSString
    //20    对应NSNumber
    
    //JSON格式格式化工具
    //  Jason
    //  Json Editor
    //  在线:  http://www.kjson.com/