Apps How to pass JSON objects from one activity to another

[Pooveshin]

Hi All

I am trying the pass JSON objects from my main activity to my second activity however Android studio picks up an error and makes it red. How would I be able to get the data to the second activity if someone can help
I am trying to get name, version, released and api to the second activity textViews.

import java.util.ArrayList;
import java.util.HashMap;

public class MainActivity extends AppCompatActivity {

    private String TAG = MainActivity.class.getSimpleName();

    private ProgressDialog pDialog;
    private ListView lv;

    // URL to get Android Version Data JSON
    private static String url = "http://codetest.cobi.co.za/androids.json";

    ArrayList<HashMap<String, String>> androidversions;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        androidversions = new ArrayList<>();

        lv = (ListView) findViewById(R.id.list);

        new GetVersions().execute();
    }

    private class GetVersions extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(MainActivity.this);
            pDialog.setMessage("Please wait...");
            pDialog.setCancelable(false);
            pDialog.show();
        }
        @Override
        protected Void doInBackground(Void... arg0) {
            HttpHandler sh = new HttpHandler();

            // Making a request to url and getting response
            String jsonStr = sh.makeServiceCall(url);

            Log.e(TAG, "Response from url: " + jsonStr);

            if (jsonStr != null) {
                try {
                    JSONObject jsonObj = new JSONObject(jsonStr);

                    // Getting JSON Array node
                    JSONArray versions = jsonObj.getJSONArray("versions");

                    // looping through All Versions
                    for (int i = 0; i < versions.length(); i++) {
                        JSONObject c = versions.getJSONObject(i);

                        String name = c.getString("name");
                        String version = c.getString("version");
                        String released = c.getString("released");
                        String api = c.getString("api");

                        // tmp hash map for single version
                        HashMap<String, String> Version = new HashMap<>();

                        // adding each child node to HashMap key => value
                        Version.put("name", name);
                        Version.put("version", version);
                        Version.put("released", released);
                        Version.put("api", api);


                        // adding Data to version list
                        androidversions.add(Version);
                    }
                } catch (final JSONException e) {
                    Log.e(TAG, "Json parsing error: " + e.getMessage());
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(getApplicationContext(),
                                    "Json parsing error: " + e.getMessage(),
                                    Toast.LENGTH_LONG)
                                    .show();
                        }
                    });

                }
            } else {
                Log.e(TAG, "Couldn't get json from server.");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(getApplicationContext(),
                                "Couldn't get json from server. Check LogCat for possible errors!",
                                Toast.LENGTH_LONG)
                                .show();
                    }
                });

            }

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                    Intent intent = new Intent(MainActivity.this, Second_Level.class);
                    intent.putExtra("json",c.toString());
                    startActivity(intent);
                }
            });
            super.onPostExecute(result);
            // Dismiss the progress dialog
            if (pDialog.isShowing())
                pDialog.dismiss();
            /**
             * Updating parsed JSON data into ListView
             * */
            ListAdapter adapter = new SimpleAdapter(
                    MainActivity.this, androidversions,
                    R.layout.list_item, new String[]{"name", "version",
                    "released", "api"}, new int[]{R.id.name,
                    R.id.version, R.id.released, R.id.api});

            lv.setAdapter(adapter);
        }

    }
}

 

[Deleted User]

Well just looking at your code, I'm guessing that the compiler doesn't like the fact that you're using variable 'c', which has not even been declared locally, its declaration is in a completely different method.

intent.putExtra("json",c.toString());

It's obvious from this that you have no understanding about the concept of variable scoping.

Honestly, if you can't see what the problem is here, the best thing you could do to help yourself is to pick up a book on the basics of Java, and read it.

 

[Deleted User]

Let me give you a hint - If you wish to share a variable in two different methods of a class, where would you declare that variable?

 

[Pooveshin]

Let me give you a hint - If you wish to share a variable in two different methods of a class, where would you declare that variable?

The answer

HashMap<String, String> version = androidversions.get(position);
String name = version.get("name");
String ver = version.get("version");
String released = version.get("released");
String api = version.get("api");