Simple Listview in fragment using SimpleAdapter

Question

Here is my code for fragment extending ListFragment and below are the errors it is showing.Almost Same code is working fine for activity except that in activity i am getting listview through

ListView lv = getListView();

and in fragment through

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

It shows nullpointer exception on line java:109 lv.setOnItemClickListener(new AdapterView.OnItemClickListener() If i remove setOnItemClickListener it shows null pointer exception on lv.setAdapter(adapter); SoundCloudFragment.java

 public class SoundCloudFragment extends ListFragment {
        private ProgressDialog pDialog;
        private FragmentActivity myContext;
        ListView lv;
        @Override
        public void onAttach(Activity activity) {

            if (activity instanceof FragmentActivity) {
                myContext = (FragmentActivity) activity;


            }

            super.onAttach(activity);
        }





        // contacts JSONArray
        JSONArray contacts = null;

        // Hashmap for ListView
        ArrayList<HashMap<String, String>> contactList;


        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            // mVisulizerView = (VisualizerView)findViewById(R.id.visualizerView);

            View rootView = inflater.inflate(R.layout.soundcloud, container, false);
            lv= (ListView)rootView.findViewById(R.id.list);
            // Get ListView object from xml


     //   lv = getListView();

          lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {

                @Override
                public void onItemClick(AdapterView<?> parent, View view,
                                        int position, long id)
                {
                    // getting values from selected ListItem
                    String name = ((TextView) view.findViewById(R.id.name)).getText().toString();
                    String cost = ((TextView) view.findViewById(R.id.email)).getText().toString();
                    String description = ((TextView) view.findViewById(R.id.mobile)).getText().toString();

                    // Starting single contact activity
                    Intent in = new Intent(myContext,
                            SingleContactActivity.class);
                    in.putExtra("name", TAG_TITLE);
                    in.putExtra("id", cost);

                    startActivity(in);

                }
            });

            // Calling async task to get json
            new GetContacts().execute();
            return rootView;
        }
        private class GetContacts extends AsyncTask<Void, Void, Void>  {

            @Override
            protected void onPreExecute() {
                super.onPreExecute();
                // Showing progress dialog
                pDialog = new ProgressDialog(myContext);
                pDialog.setMessage("Please wait...");
                pDialog.setCancelable(false);
                pDialog.show();

            }

            @Override
            protected Void doInBackground(Void... arg0) {
                // Creating service handler class instance
                ServiceHandler sh = new ServiceHandler();

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

                Log.d("Response: ", "> " + jsonStr);

                if (jsonStr != null) {
                    try {
                        JSONArray json = new JSONArray(jsonStr);

                        // looping through All Contacts
                        for (int i = 0; i < json.length(); i++) {
                            JSONObject jsonObj = json.getJSONObject(i);
                            //JSONObject c = contacts.getJSONObject(i);

                            String title = jsonObj.getString(TAG_TITLE);
                            String id = jsonObj.getString(TAG_ID);
                            String kind = jsonObj.getString(TAG_KIND);
                            String duration =jsonObj.getString(TAG_DURATION);
                        /*  String gender = c.getString(TAG_GENDER);

                            // Phone node is JSON Object
                            JSONObject phone = c.getJSONObject(TAG_PHONE);
                            String mobile = phone.getString(TAG_PHONE_MOBILE);
                            String home = phone.getString(TAG_PHONE_HOME);
                            String office = phone.getString(TAG_PHONE_OFFICE);*/

                            // tmp hashmap for single contact
                            HashMap<String, String> contact = new HashMap<String, String>();

                            // adding each child node to HashMap key => value
                            contact.put(TAG_TITLE, title);
                            contact.put(TAG_ID, id);
                            contact.put(TAG_KIND, kind);
                            contact.put(TAG_DURATION, duration);


                            // adding contact to contact list
                            contactList.add(contact);
                        }
                    } catch (JSONException e)
                    {
                        e.printStackTrace();
                    }
                } else {
                    Log.e("ServiceHandler", "Couldn't get any data from the url");
                }

                return null;
            }

            @Override
            protected void onPostExecute(Void result) {
                super.onPostExecute(result);
                // Dismiss the progress dialog
                if (pDialog.isShowing())
                    pDialog.dismiss();
                /**
                 * Updating parsed JSON data into ListView
                 * */
                ListAdapter adapter = new SimpleAdapter(
                        myContext, contactList,
                        R.layout.soundcloud_item, new String[] { TAG_TITLE, TAG_ID,
                        TAG_KIND }, new int[] { R.id.name,
                        R.id.email, R.id.mobile });

              lv.setAdapter(adapter);

            }

        }


    }

Errors-

 FATAL EXCEPTION: main
        java.lang.NullPointerException
                at com.peoplecloud.guggu.ui.fragment.SoundCloudFragment.onCreateView(SoundCloudFragment.java:109)
                at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:829)
                at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1035)
                at android.app.BackStackRecord.run(BackStackRecord.java:635)
                at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1397)
                at android.app.FragmentManagerImpl$1.run(FragmentManager.java:426)
                at android.os.Handler.handleCallback(Handler.java:615)
                at android.os.Handler.dispatchMessage(Handler.java:92)
                at android.os.Looper.loop(Looper.java:153)
                at android.app.ActivityThread.main(ActivityThread.java:5086)
                at java.lang.reflect.Method.invokeNative(Native Method)
                at java.lang.reflect.Method.invoke(Method.java:511)
                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:821)
                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:584)
                at dalvik.system.NativeStart.main(Native Method)

Answer 1

Try this way,hope this will help you to solve your problem.

There is two way to given ListView id.

1.android predefined id like :

XML

<ListView
   android:id="@android:id/list"

Activty

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

Fragment

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

2.Custom id like :

XML

<ListView
   android:id="@+id/list"

Activty

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

Fragment

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

Answer 2

Try using this code to get your ListView:

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

As you are using a ListFragment as the base class. Also you probably would need to use android.R.id.list to get your list if you put it correctly in your xml file.

Answer 3

try this.

ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.soundcloud, container, false);

and also in your onItemClick

// Starting single contact activity

Intent in = new Intent(getActivity().getApplicationContext(),
                   SingleContactActivity.class);
          in.putExtra("name", TAG_TITLE);
          in.putExtra("id", cost);
          startActivity(in);