Pull specific JSON objects from a specific array to put in another activity by an Intent in Android

Question

I am creating a News Feed App, and I want to be able to pull information from a specific listing to a different layout that displays the title, source, image and content of the news listing. On the main page, the JSON will populate the list view with the title, source and image. I've sent an onItemClickListener, and when I click on each entry, I want it to open that entry in the new layout to display all the content. I have a class made just to pull the JSON info, so I'm not sure how to use that in the class with the onItemClick listener. I understand the putExtra, but I'm completely lost on the code to enter to transfer over what I need. Below is code from the page with the list, as well as the JsonQuery class. Thanks for any help!

TopHeadlinesFragment.java

public class TopHeadlinesFragment extends Fragment
        implements LoaderManager.LoaderCallbacks<List<News>> {

    public static final String NEWS_FEED_URL =
            "https://newsapi.org/v2/top-headlines?country=us&apiKey=a3f791903c1a4163b223dd033563084b";

    private static final int NEWS_LOADER_ID = 1;
    private NewsAdapter mNewsAdapter;
    private NewsAdapterListing mNewsAdapterListing;


    public TopHeadlinesFragment(){
        // Required empty public constructor
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.news_list, container, false);

        mNewsAdapter = new NewsAdapter(getActivity(), new ArrayList<News>());

        ListView listView = rootView.findViewById(R.id.list);

        listView.setAdapter(mNewsAdapter);

        final LoaderManager loaderManager = getLoaderManager();
        loaderManager.initLoader(NEWS_LOADER_ID, null, this);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                mNewsAdapterListing = new NewsAdapterListing(getActivity(), new ArrayList<News>());
                News currentNews = mNewsAdapterListing.getItem(position);
                Intent newsArticleDisplayIntent = new Intent(getActivity(), FullArticleListing.class);

                startActivity(newsArticleDisplayIntent);

            }
        });

        return rootView;
    }


    @Override
    public Loader<List<News>> onCreateLoader(int id, Bundle args) {
        return new NewsLoader(getActivity(), NEWS_FEED_URL);
    }

    @Override
    public void onLoadFinished(Loader<List<News>> loader, List<News> data) {
        mNewsAdapter.clear();

        if (data != null && !data.isEmpty()){
            mNewsAdapter.addAll(data);
        }
    }

    @Override
    public void onLoaderReset(Loader<List<News>> loader) {
        mNewsAdapter.clear();
    }

    public static class NewsLoader extends AsyncTaskLoader<List<News>> {
        private String[] mUrl;

        public NewsLoader(Context context, String... url) {
            super(context);
            mUrl = url;
        }

        @Override
        protected void onStartLoading() {
            forceLoad();
        }

        @Override
        public List<News> loadInBackground() {
            if (mUrl.length < 1 || mUrl[0] == null) {
                return null;
            }
            return JsonQueryUtils.fetchNewsData(mUrl[0]);
        }
    }
}

JsonQueryUtils.java

public class JsonQueryUtils {

    /** Contains networking and JSON parsing code **/

    private static final String LOG_TAG = "JsonQueryUtils";

    private JsonQueryUtils(){
    }

    /** Helper method to fetch news data and call networking code within method **/

    public static List<News> fetchNewsData(String requestUrl){
        URL url = createUrl(requestUrl);
        String jsonResponse = null;
        try{
            jsonResponse = makeHttpRequest(url);
        } catch (IOException e){
            Log.e(LOG_TAG, "Error closing input stream", e);
        }

        List<News> news = extractNews(jsonResponse);
        Log.i(LOG_TAG, "fetchNewsData initialized");
        return news;
    }

    private static List<News> extractNews (final String newsJSON) {
        if (TextUtils.isEmpty(newsJSON)) {
            return null;
        }

        List<News> news = new ArrayList<>();

        try {
            JSONObject jsonNewsObject = new JSONObject(newsJSON);
            JSONArray newsArray = jsonNewsObject.getJSONArray("articles");

            for (int i = 0; i < newsArray.length(); i++) {
                JSONObject currentNews = newsArray.getJSONObject(i);
                JSONObject source = currentNews.optJSONObject("source");

                String imageUrl = currentNews.getString("urlToImage");
                Bitmap newsImage = makeHttpRequest(imageUrl);

                String title = currentNews.getString("title");
                String sourceName = source.getString("name");
                String content = currentNews.getString("content");

                news.add(new News(newsImage, title, sourceName));

            }
        } catch (JSONException e) {
            e.printStackTrace();
            Log.e(LOG_TAG, "problem with parsing", e);
        } catch (IOException e){
            e.printStackTrace();
        }
        return news;
    }

    /**
     * Make an HTTP request to the given imageURL and return a Bitmap as the response.
     */
    private static Bitmap makeHttpRequest (String imageUrl) throws IOException {
        Bitmap newsImage = null;
        if (imageUrl == null){
            return newsImage;
        }

        URL url = createUrl(imageUrl);
        HttpURLConnection urlConnection = null;
        InputStream inputStream = null;
        try {
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("GET");
            urlConnection.setDoInput(true);
            urlConnection.connect();
            if (urlConnection.getResponseCode() == 200) {
                inputStream = urlConnection.getInputStream();
                newsImage = BitmapFactory.decodeStream(inputStream);
            }

        } catch (IOException e) {
            Log.e(LOG_TAG, "Error reading bitmap input stream");
        } finally {
            if (urlConnection != null) {
                urlConnection.disconnect();
            }
            if (inputStream != null) {
                inputStream.close();
            }
        }
        return newsImage;
    }



    /**
     * Make an HTTP request to the given URL and return a String as the response.
     */
    private static String makeHttpRequest(URL url) throws IOException {
        String jsonResponse = "";

        // If the URL is null, then return early.
        if (url == null) {
            return jsonResponse;
        }

        HttpURLConnection urlConnection = null;
        InputStream inputStream = null;
        try {
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setReadTimeout(10000 /* milliseconds */);
            urlConnection.setConnectTimeout(15000 /* milliseconds */);
            urlConnection.setRequestMethod("GET");
            urlConnection.connect();

            // If the request was successful (response code 200),
            // then read the input stream and parse the response.
            if (urlConnection.getResponseCode() == 200) {
                inputStream = urlConnection.getInputStream();
                jsonResponse = readFromStream(inputStream);
            } else {
                Log.e(LOG_TAG, "Error response code: " + urlConnection.getResponseCode());
            }
        } catch (IOException e) {
            Log.e(LOG_TAG, "Problem reading input stream.", e);
        } finally {
            if (urlConnection != null) {
                urlConnection.disconnect();
            }
            if (inputStream != null) {
                inputStream.close();
            }
        }
        return jsonResponse;
    }

    /**
     * Convert the {@link InputStream} into a String which contains the
     * whole JSON response from the server.
     */
    private static String readFromStream(InputStream inputStream) throws IOException {
        StringBuilder output = new StringBuilder();
        if (inputStream != null) {
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
            BufferedReader reader = new BufferedReader(inputStreamReader);
            String line = reader.readLine();
            while (line != null) {
                output.append(line);
                line = reader.readLine();
            }
        }
        return output.toString();
    }

    /** Helper method to create {@link} URL object **/
    private static final URL createUrl(String stringUrl) {
        URL url = null;
        try {
            url = new URL(stringUrl);
        } catch (MalformedURLException e) {
            Log.e(LOG_TAG, "createUrl: error", e);
        }
        return url;
    }


}

Answer 1

I noticed you extracted the 'content' from JSON response but I don't see anywhere the variable 'content' getting used to construct the News object... Is there a reason why you don't include it to News object?

Regarding sending the News object to the next activity, there are few ways to achieve this.

1. Use Parcelable to send the News to your next activity/fragment. For more details, click here.

2. Install GSON library and simple convert your News object to Json String. Put that String in your Intent as an extra and launch the next Activity. Retrieve the data by calling new Gson().fromJson(). However, since your object has Bitmap field, this won't be a suitable approach. For more details, click here

3. This is what I would have done, if the API allows: Simply call the API request again for more details about the current feed. For example, you can execute another API request in your FullArticleActivity along with an ID that is associated with the selected feed. (i.e. User clicks a feed with an id #3 -> Pass the id(Integer) to the next Activity as an extra -> Retrieve the id from extras and make another API request using the id to retrieve full article details.) However, this is possible only when your API provides a GET method like this.

4. Create a Singleton and let it hold your object temporarily. Retrieve the object in the next activity by simple calling something like YourSingletonClass.getInstance().getNews().