如何在JSON数组的嵌套JSON对象中获取一些元素

Question

I hava this JSON:

[
  {

    "title": "This a Sample title for each post_title",

    "excerpt": "And this is a sample of the post_body,

    "author": "King Spark",

    "featured_picture": {

      "source": "https://exapmple.com/blah/blah/image.jpg",
      "year": "2015",
      "ownwer": "Akim Man",

    },

  },...

From the json I only need the title , excerpt elements of the main objects. Then from the featured_picture objects, I want only the source element.

I have written this code and it seems not to be working:

private void parseData(JSONArray array){
        Log.d(TAG, "Parsing array");

        for(int i = 0; i<array.length(); i++) {
            PostItems postItem = new PostItems();
            JSONObject jsonObject = null;
            try {
                jsonObject = array.getJSONObject(i);
                postItem.setPost_title(jsonObject.getString(ConfigPost.TAG_POST_TITLE));
                postItem.setPost_body(jsonObject.getString(ConfigPost.TAG_POST_BODY));

                //Parsing featured_pocture object


                for (int f = 0; f<array.length(); f++) {
                    JSONObject object = array.getJSONObject(f);
                    JSONObject postImage = object.getJSONObject("featured_picture");
                    String imageURL = postImage.getString("source");
                    postItem.setPost_image(imageURL);
                }





            } catch (JSONException w) {
                w.printStackTrace();
                //Toast.makeText(this, "Error in parsing Json", Toast.LENGTH_LONG).show();
            }
            mPostItemsList.add(postItem);
        }

    }

Answer 1

You won't continue read the array here

for (int f = 0; f<array.length(); f++) {

featured_picture is an entry in the map and returns a map too.

The acces should be like this :

array.getJSONObject(i).getJSONObject("featured_picture").getString("source");

Answer 2

你必须通过钥匙识别JSON对象和数组，然后发现价值，一旦你学会了，然后JSON的复杂性没有关系解析跟着教程

Answer 3

your code for (int f = 0; f<array.length(); f++) { JSONObject object = array.getJSONObject(f); JSONObject postImage = object.getJSONObject("featured_picture"); String imageURL = postImage.getString("source"); postItem.setPost_image(imageURL); } for (int f = 0; f<array.length(); f++) { JSONObject object = array.getJSONObject(f); JSONObject postImage = object.getJSONObject("featured_picture"); String imageURL = postImage.getString("source"); postItem.setPost_image(imageURL); } for (int f = 0; f<array.length(); f++) { JSONObject object = array.getJSONObject(f); JSONObject postImage = object.getJSONObject("featured_picture"); String imageURL = postImage.getString("source"); postItem.setPost_image(imageURL); } is not correct, this part of json is not an array but an object inside another jsonObject.

Answer 4

Try to parse the nested JSON like this way:

   private void parseData(JSONArray array){
    Log.d(TAG, "Parsing array");

    for(int i = 0; i<array.length(); i++) {
        PostItems postItem = new PostItems();
        JSONObject jsonObject = null;
        try {
            jsonObject = array.getJSONObject(i);

   postItem.setPost_title(jsonObject.getString(ConfigPost.TAG_POST_TITLE));

   postItem.setPost_body(jsonObject.getString(ConfigPost.TAG_POST_BODY));

    //Parsing featured_picture object
   JSONObject postImage = jsonObject.getJSONObject("featured_picture");

   postItem.setPost_image(postImage.getString("source"));


        } catch (JSONException w) {
            w.printStackTrace();
            //Toast.makeText(this, "Error in parsing Json", Toast.LENGTH_LONG).show();
        }
        mPostItemsList.add(postItem);
    }

}

Answer 5

Here no need to iterate loop to read nested JSONobject .

Because "featured_picture" gives only JSONObject not an array. In case if its return array you should read like this:

JSONObject rootObject=new JSONObject();
JSONArray nestedObject=rootObject.getJSONArray("key");

Here i modified your code in correct manner hope will it help for you.

 for(int i = 0; i<array.length(); i++) {
            PostItems postItem = new PostItems();
            JSONObject jsonObject = null;
            try {
                jsonObject = array.getJSONObject(i);
                   postItem.setPost_title(jsonObject.getString(ConfigPost.TAG_POST_TITLE));
                postItem.setPost_body(jsonObject.getString(ConfigPost.TAG_POST_BODY));

                //Parsing featured_pocture object

 JSONObject postImage = jsonObject.getJSONObject("featured_picture");
   String imageURL = postImage.getString("source");
         postItem.setPost_image(imageURL);


            } catch (JSONException w) {
                w.printStackTrace();
                //Toast.makeText(this, "Error in parsing Json", Toast.LENGTH_LONG).show();
            }