如何使用数组对Dictionary进行属性解析/传播

Question

我正试图传播NSJSONSerialization的响应：

let responseDict = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &jsonError) as NSDictionary

到目前为止，我有一个很好的输出，我想剖析/传播：

(lldb) po responseDict
{
    photos =     {
        page = 1;
        pages = 1333;
        perpage = 100;
        photo =         (
                        {
                farm = 4;
                "height_m" = 243;
                "height_s" = 117;
                "height_sq" = 75;
                "height_t" = 49;
                id = 15148883617;
                isfamily = 0;
                isfriend = 0;
                ispublic = 1;
                owner = "48531100@N04";
                secret = fb6596ca90;
                server = 3926;
                title = "An Exceptional Roman Orichalcum Sestertius of Nero (54-68 C.E.), a Magnificent Depiction of the Temple of Janus on the Reverse";
                "url_m" = "https://farm4.staticflickr.com/3926/15148883617_fb6596ca90.jpg";
                "url_s" = "https://farm4.staticflickr.com/3926/15148883617_fb6596ca90_m.jpg";
                "url_sq" = "https://farm4.staticflickr.com/3926/15148883617_fb6596ca90_s.jpg";
                "url_t" = "https://farm4.staticflickr.com/3926/15148883617_fb6596ca90_t.jpg";
                "width_m" = 500;
                "width_s" = 240;
                "width_sq" = 75;
                "width_t" = 100;
            },
            ...
            ...

问题在于传播。以下是"照片"键的内容（与ObjC对应键相比相当难看）：

(lldb) po responseDict["photos"]
(instance_type = Builtin.RawPointer = 0x00007fce90ec74e0 -> 0x0000000105a910e0 (void *)0x0000000105a91220: __NSDictionaryM)
 {
  instance_type = 0x00007fce90ec74e0 -> 0x0000000105a910e0 (void *)0x0000000105a91220: __NSDictionaryM
}

这条线会产生致命的（动态投射）崩溃：

let myPhotos = responseDict["photos"] as NSArray

这里有一个ObjC等价物（有效）：

jsonDict[@"photos"][@"photo"];

将其与以下Swift等价物进行比较，后者会给我一个错误（尽管我已经将其向下转换为NSDictionary）：

(lldb) po responseDict["photos"]["photo"]
error: <EXPR>:1:1: error: 'AnyObject?' does not have a member named 'subscript'
responseDict["photos"]["photo"]

问题：如何像在Objective-C中那样正确地剖析Swift中的词典（或任何集合）？

Answer 1

我设法找到了单独的字典：

let myPhotos = responseDict["photos"] as? NSDictionary
let photos = myPhotos!["photo"] as? NSArray
let myPhoto:AnyObject = photos![0]
println(myPhoto)

以下是输出：

{
    farm = 4;
    "height_m" = 500;
    "height_s" = 240;
    "height_sq" = 75;
    "height_t" = 100;
    id = 15150188169;
    isfamily = 0;
    isfriend = 0;
    ispublic = 1;
    owner = "87355413@N02";
    secret = e9cfed5225;
    server = 3905;
    title = "Miss 18mths wearing Music Box pinafore in grey denim (18-24mths). Trimmed with aqua/pink ric rac, and "bow" button.";
    "url_m" = "https://farm4.staticflickr.com/3905/15150188169_e9cfed5225.jpg";
    "url_s" = "https://farm4.staticflickr.com/3905/15150188169_e9cfed5225_m.jpg";
    "url_sq" = "https://farm4.staticflickr.com/3905/15150188169_e9cfed5225_s.jpg";
    "url_t" = "https://farm4.staticflickr.com/3905/15150188169_e9cfed5225_t.jpg";
    "width_m" = 375;
    "width_s" = 180;
    "width_sq" = 75;
    "width_t" = 75;
}

进一步测试：

let myPhoto = myPhotoInfo["url_m"] as String

产品：

https://farm4.staticflickr.com/3920/15333895891_956d072454.jpg

Answer 2

从工作的Objective-C代码来看，responseDict["photos"]不是NSArray，而是NSDictionary。这应该有效：

let myPhotos = responseDict["photos"] as? NSDictionary
let photo = myPhotos!["photo"]