ios - objective-c/JSON : How to get ObjectForKey when it's a top level object

Question

我的 JSON 看起来像这样:

[
  {
    post_number: "1",
    date: "2013-09-02",
    thumbnail: "thumbnail_address"
  },
  {
    post_number: "2",
    date: "2013-09-02",
    thumbnail: "thumbnail_address"
  },
  {
    post_number: "2",
    date: "2013-09-02",
    thumbnail: "thumbnail_address"
  },
]

我通常做这样的事情 NSArray *blogPostsArray = [dataDictionary objectForKey:@"posts"]; 但没有一个名为“posts”的顶级对象。当 Objective -c 中没有顶级对象时，如何获取数组？

提前谢谢你..

Answer 1

如果您的顶级对象是数组而不是字典，NSJSONSerialization 将创建一个 NSArray 实例而不是 NSDictionary。
因此，您可以通过 objectAtIndex:(或通过现代 Objective-C 中的 [])检索包含的对象:

NSArray* jsonArray = @[@{
                           @"post_number": @"1",
                           @"date": @"2013-09-02",
                           @"thumbnail": @"thumbnail_address"
                      },
                      @{
                           @"post_number": @"2",
                           @"date": @"2013-09-02",
                           @"thumbnail": @"thumbnail_address"
                      },
                      @{
                           @"post_number": @"2",
                           @"date": @"2013-09-02",
                           @"thumbnail": @"thumbnail_address"
                        }];
NSData* jsonData = [NSJSONSerialization dataWithJSONObject:jsonArray options:0 error:nil];
NSArray* deserializedArray = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:nil];
NSDictionary* first = deserializedArray[0];
NSLog(@"%@", first);