如何解析嵌套的 JSON

Question

Thank you reading my post, I known this topic was asked so many time, and I had saw that but no luck...

I want to parse a simple JSON string, as followings:

[
   {
      "id":"1",
      "name_en":"Photography",
      "subchannels":[
         {
            "id":"4",
            "name_en":"John"
         },
         {
            "id":"18",
            "name_en":"Sam"
         }
      ]
   },
   {
      "id":"7",
      "name_en":"Equipment",
      "subchannels":[
         {
            "id":"25",
            "name_en":"ABC Company"
         },
         {
            "id":"40",
            "name_en":"CDE Company"
         }
      ]
   }
]

It had convert this string to NSDictionary

NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];

NSDictionary *testDic = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&e];

Then I list the Dictionary Key

for(id key in testDic) {
        NSLog(@"%@", key);
    }

The result is the entire record as the Dictionary Key, so I can't use [testDic objectForKey:key] to retrieve the value.

How can I get the first row name_en and the second row subchannels value? (is it possible to retrieve easily like xpath in XML?)

Thank you for helping.

Answer 1

First of all. The root object of your model is NSArray object - not `NSDictionary. '[]' means array and {} means dictionary.

NSArray *dataArray = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&e];

for (NSDictionary *entry in dataArray) {
  NSString *name = entry[@"name_en"];
  NSArray *subchannels = entry[@"subchannels"]; //array of dictionaries

  NSLog(@"Name %s", name); 

  for  (NSDictionary *subchannel in subchannels) {
     NSLog(@"Subchannels name %@ id: %d", subchannel[@"name"], [subchannel[@"id"] integerValue]);
  }
}

If you want to perform advances JSON parsing I encourage you to look at Mantle github project .