如何获取json数组的子节点的值

Question

请我在解析此链接中的数据列表时遇到一些问题（https://gnews.io/api/v3/top-news?&token=dd21eb88599ccb3411eaad9b314cde23）我能够从 json 数组（文章）中获取数据，但是我如何从 josn 数组中获取数据（来源)

    private void getWebApiData() {
        String WebDataUrl = "https://gnews.io/api/v3/top-news?&token=dd21eb88599ccb3411eaad9b314cde23";
        new AsyncHttpTask.execute(WebDataUrl);
    }

    @SuppressLint("StaticFieldLeak")
    public class AsyncHttpTask extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... urls) {
            String result = "";

            URL url;
            HttpsURLConnection urlConnection = null;
            try {
                url = new URL(urls[0]);
                urlConnection = (HttpsURLConnection) url.openConnection();
                if (result != null) {
                    String response = streamToString(urlConnection.getInputStream());
                    parseResult(response);
                    return result;
                }
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(String result) {
            if (result != null) {
                newsAdapter = new NewsAdapter(getActivity(), newsClassList);
                listView.setAdapter(newsAdapter);
                Toast.makeText(getContext(), "Data Loaded Successfully", Toast.LENGTH_SHORT).show();

            } else {
                Toast.makeText(getContext(), "Failed to load data!", Toast.LENGTH_SHORT).show();
            }
            progressBar.setVisibility(View.GONE);
        }
    }

    private String streamToString(InputStream stream) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(stream));
        String line;
        String result = "";
        while ((line = bufferedReader.readLine()) != null) {
            result += line;
        }

        // Close stream
        if (null != stream) {
            stream.close();
        }
        return result;
    }


    private void parseResult(String result) {
        try {
            JSONObject response = new JSONObject(result);
            JSONObject response2 = response.getJSONObject("articles");
            NewsClass newsClass;
            for (int i = 0; i < newsClass.length(); i++) {
                JSONObject post = newsClass.optJSONObject(i);
                String name = post.optString("name");
                newsClass = new newsClass();
                newsClass.setNews_Name(name);
                artistClassList.add(newsClass);
            }

        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

这是我用来获取文章数据的代码。 获取我尝试过的来源

    private void parseResult(String result) {
        try {
            JSONObject response = new JSONObject(result);
            JSONObject response2 = response.getJSONArray("articles");
            JSONObject response3 = response2.getJSONObject("sources");
            NewsClass newsClass;
            for (int i = 0; i < newsClass.length(); i++) {
                JSONObject post = newsClass.optJSONObject(i);
                String name = post.optString("name");
                newsClass = new newsClass();
                newsClass.setNews_Name(name);
                artistClassList.add(newsClass);
            }

        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

但我认为我没有正确获取代码

这是我尝试过的第二个选项

    private void parseResult(String result) {
        try {
            JSONObject response = new JSONObject(result);

            JSONObject response = response2.getJSONObject("sources");
            NewsClass newsClass;
            for (int i = 0; i < newsClass.length(); i++) {
                JSONObject post = newsClass.optJSONObject(i);
                String name = post.optString("name");
                newsClass = new newsClass();
                newsClass.setNews_Name(name);
                artistClassList.add(newsClass);
            }

        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

但这只会给我空文本字段填充数据的空格但它是空白的 请任何帮助将不胜感激

Answer 1

我不知道您的代码是如何工作的。您尝试将JSONObject 作为articles，实际上是JSONArray。除此之外，我在您的 json 中没有找到任何 key，例如 sources，而是找到了 source。要解析 source 请尝试以下方式：

try {
    JSONObject jsonObject = new JSONObject(result);
    JSONArray jsonArray = jsonObject.getJSONArray("articles");

    for(int i = 0; i < jsonArray.length(); i++) {
        JSONObject articleObject = jsonArray.getJSONObject(i);
        JSONObject sourceObject = articleObject.getJSONObject("source");

        String name = sourceObject.optString("name");
        String url = sourceObject.optString("url");
    }
} catch (JSONException e) {
    e.printStackTrace();
}

Answer 2

正如 Asaduzzaman 博士所说，它实际上是一个 JSON 数组（准确地说是“文章”）。

我已经在我的手机上测试过，它没有问题。您将不得不尝试弄清楚您希望如何解析 JSONArray。

private class AsyncTaskExample extends AsyncTask<String, String, String> {


    @Override
    protected void onPreExecute() {

    }
    @Override
    protected String doInBackground(String... strings) {
        try {
            stringURL = new URL(strings[0]);
            HttpURLConnection conn = (HttpURLConnection) stringURL.openConnection();
            conn.setDoInput(true);
            conn.connect();
            is = conn.getInputStream();

            //render string stream
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(is));
            String line;
            String result = "";
            while ((line = bufferedReader.readLine()) != null) {
                result += line;
            }

            // Close stream
            if (null != is) {
                is.close();
            }

            return result;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return str;
    }

    @Override
    protected void onPostExecute(String js) {
        super.onPostExecute(js);
        try {
            JSONObject  jay = new JSONObject (js);
            JSONObject source = jay.getJSONObject("articles");

            String s = source.getString("title");
            System.out.println(s);
        } catch (JSONException e) {
            e.printStackTrace();
        }

    }

}

在这里您可以找到JSON 所需的一切。

祝你好运:)

Answer 3

JSONObject jsonObject = new JSONObject(response.body().string());
            JSONArray articles = jsonObject.getJSONArray("articles");
            for(int i=0; i<articles.length(); i++){
                JSONObject obj1 = (JSONObject) articles.get(i);
                JSONObject source = obj1.getJSONObject("source");
                Log.i(TAG, "onResponse: " + source.toString()); }

希望对您有所帮助！