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How can I get ArrayList back to fragment from parser class after parsing data and ArrayList send to fragment to set in Recyclerview adapter?

How can I get array list back to fragment after parsing to set into RecyclerView.
I tried to do that but when I call api it run background thread, till I get ArrayList from background my fragment created and it set null array to recycler adapter.
Then, I tried this way its working but I think it is a wrong approach. Please guide me -
How can I set adapter in Fragment after parsing data and send ArrayList back to fragment and set to RecyclerView adapter?
Here is my code fragment code
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
setHasOptionsMenu(true);
View view=inflater.inflate(R.layout.first_fragment,null);
recyclerView=(RecyclerView)view.findViewById(R.id.mFirstRecyclerview);
recyclerView.setLayoutManager(new LinearLayoutManager(this.getActivity()));
mswipeRefreshLayout = (SwipeRefreshLayout)view.findViewById(R.id.swipelayoutm);
ParseDataClass mparser = new ParseDataClass(getActivity(),recyclerView,mswipeRefreshLayout);
mparser.execute("http://192.168.8.100/fetchtext.php", "1");
recyclerView.setOnScrollChangeListener(new View.OnScrollChangeListener() {
#Override
public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
if (scrollX == 0) {
mswipeRefreshLayout.setEnabled(true);
} else mswipeRefreshLayout.setEnabled(false);
}
});
return view;
}
#Override
public String toString() {
return "FirstFragment";
}
#Override
public void onPrepareOptionsMenu(Menu menu) {
menu.findItem(R.id.rightimageitem).setVisible(false);
super.onPrepareOptionsMenu(menu);
}
}
And Here it is my parser class
public ParseDataClass(Context context,RecyclerView recyclerView,SwipeRefreshLayout swipeRefreshLayout) {
this.context = context;
progressDialog = new ProgressDialog(this.context);
progressDialog.setCancelable(false);
progressDialog.setMessage("Retrieving data...");
progressDialog.setTitle("Please wait");
progressDialog.setIndeterminate(true);
arrayList = new ArrayList<DataStored>();
getArraylist = new ArrayList<DataStored>();
this.recyclerView=recyclerView;
this.swipeRefreshLayout=swipeRefreshLayout;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog.show();
}
private static final String TAG = "Parser";
#Override
protected String doInBackground(String... strings) {
URL url = null;
int arryLength = strings.length;
HttpURLConnection httpURLConnection = null;
try {
url = new URL(strings[0]);
String catId = strings[1];
httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
httpURLConnection.setDoInput(true);
OutputStream outputStream = httpURLConnection.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
String post_data = URLEncoder.encode("catId", "UTF-8") + "=" + URLEncoder.encode(catId, "UTF-8");
bufferedWriter.write(post_data);
bufferedWriter.flush();
bufferedWriter.close();
outputStream.close();
InputStream inputStream = httpURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"));
String result = "";
String line = "";
while ((line = bufferedReader.readLine()) != null) {
result += line;
}
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return result;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
try {
// RestaurantData restaurantData;
if (s != null) {
JSONObject jsonObject = new JSONObject(s);
JSONArray jsonArray = jsonObject.getJSONArray("result");
for (int i = 0; i < jsonArray.length(); i++) {
jsonObject = jsonArray.getJSONObject(i);
String branchname = jsonObject.getString("brancname");
String branchaddress = jsonObject.getString("branchaddres");
String brandname = jsonObject.getString("brandsNae");
String brandlogo = jsonObject.getString("brndlogo");
String branchlogo = jsonObject.getString("brnchlogo");
String discAmount = jsonObject.getString("distAmount");
dataStored = new DataStored(branchname, branchaddress, brandname, brandlogo, branchlogo, discAmount);
arrayList.add(dataStored);
}
myAdapter = new MyRecyclerAdapter(context, arrayList, swipeRefreshLayout);
if (progressDialog != null && progressDialog.isShowing()) {
progressDialog.dismiss();
}
recyclerView.setAdapter(myAdapter);
} else {
if (progressDialog != null && progressDialog.isShowing()) {
progressDialog.dismiss();
}
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED ||
connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED) {
//we are connected to a network
connected = true;
} else {
connected = false;
}
if (connected == false) {
Toast.makeText(context, "Null Data", Toast.LENGTH_LONG).show();
recyclerView.setAdapter(null);
}
}
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(context, "Error in Parsing =" + e, Toast.LENGTH_LONG).show();
if (progressDialog != null && progressDialog.isShowing()) {
progressDialog.dismiss();
}
}
}
Now I am setting recycler view in parser class not in fragment my question is ..
how can I get ArrayList back to fragment after parsing then set into recylerview adapter in fragment.

How can I set adapter in Fragment after parsing data and send
ArrayList back to fragment and set to RecyclerView adapter?
Simple,
Step 1: Create an interface
public interface OnDataRetrievalCallback {
void onDataRetrieval(ArrayList<DataStored> dataSet);
}
Step 2: Create interface instance and setter in your Parser class
public class ParseDataClass extends AsyncTask<...> {
....
...
arrayList = new ArrayList<DataStored>();//Your arrayList to be filled
private OnDataRetrievalCallback onDataRetrievalCallback;
public void setOnDataRetrievalCallback(OnDataRetrievalCallback callback) {
this.onDataRetrievalCallback = callback;
}
// You can send the data back to Fragment via onDataRetrievalCallback
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
// After parsing and filling up the data into arrayList
onDataRetrievalCallback.onDataRetrieval(arrayList); //arrayList to be sent
}
}
Step 3: set DataRetrievalCallback from your Fragment
public class MyFragment extends Fragment {
#Override
onCreateView(.....) {
ParseDataClass mparser = new ParseDataClass(getActivity(),recyclerView,mswipeRefreshLayout);
mparser.setOnDataRetrievalCallback(new OnDataRetrievalCallback{
public void onDataRetrieval(ArrayList<DataStored> dataSet) {
//dataSet is your arrayList, use it to set the adapter
}
});
mparser.execute("http://192.168.8.100/fetchtext.php", "1");
}
}

GridView is blank after updating its data after scrolling down

I am usind TMDb API to build a project app. Every api call gives me back 20 movies, so normally the app shows only 20 movie posters on startup. I added this code to fetch another 20 movies, using the &page= query, when the user scrolls down the grid View.
gridView.setOnScrollListener(onScrollListener());
private AbsListView.OnScrollListener onScrollListener() {
return new AbsListView.OnScrollListener() {
#Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
int threshold = 1;
int count = gridView.getCount();
if (scrollState == SCROLL_STATE_IDLE) {
if (gridView.getLastVisiblePosition() >= count - threshold && pageCount < 2) {
Log.v(LOG_TAG, "loading more data");
// Execute LoadMoreDataTask AsyncTask
updateMovies(sortBy, true);
}
}
}
#Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount,
int totalItemCount) {
}
};
}
But this solution works really bad. If i scroll down it executes updateMovies(sortBy, true); for 2-3 times at once, jumping pages and making it impossible to read.
Also, the data shown on screen is completely replaced after every page refresh, for example if I am seeing the data on page=1 and I scroll down then i see only the data from page 2 or 3 but the original data is gone.
here is my AsyncTask
public class FetchMoviesTask extends AsyncTask<String, Void, List<Movie>> {
private final String LOG_TAG = FetchMoviesTask.class.getSimpleName();
private final static String API_KEY = "480a9e79c0937c9f4e4a129fd0463f96";
#Override
protected List<Movie> doInBackground(String... params) {
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
String jsonStr = null;
try {
final String BASE_URL = "http://api.themoviedb.org/3/movie";
final String API_KEY_PARAM = "api_key";
final String PAGE_PARAM = "page";
URL url;
if (params[1].equals("true")){
// if a bool is true
// then I intend to load an additional page
// (needed otherwise going back from detailAct loads a new increasing page
currentPage += 1;
pageCount++;
}else{
currentPage = 1;
}
if (params[0].equals(POPULARITY_DESC)){
Uri builtUri = Uri.parse(BASE_URL).buildUpon()
.appendPath("popular")
.appendQueryParameter(API_KEY_PARAM, API_KEY) // my own API key
.appendQueryParameter(PAGE_PARAM , Integer.toString(currentPage))
.build();
url = new URL(builtUri.toString());
}else if(params[0].equals(RATING_DESC)) {
Uri builtUri = Uri.parse(BASE_URL).buildUpon()
.appendPath("top_rated")
.appendQueryParameter(API_KEY_PARAM, API_KEY)// my own API key
.appendQueryParameter(PAGE_PARAM , Integer.toString(currentPage))
.build();
url = new URL(builtUri.toString());
}else {
Log.v(LOG_TAG, "Something went wrong with URI building :(");
url = new URL("ERROR URL");
}
Log.v(LOG_TAG, "URL BUILT: " + url);
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
// Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
// But it does make debugging a *lot* easier if you print out the completed
// buffer for debugging.
buffer.append(line + "\n");
}
if (buffer.length() == 0) {
return null;
}
jsonStr = buffer.toString(); // finally parsed JSON string
} catch (IOException e) {
Log.e(LOG_TAG, "Error ", e);
return null;
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e(LOG_TAG, "Error closing stream", e);
}
}
}
try {
return getMoviesDataFromJson(jsonStr);
} catch (JSONException e) {
Log.e(LOG_TAG, e.getMessage(), e);
e.printStackTrace();
}
// This will only happen if there was an error getting or parsing the forecast.
return null;
}
private List<Movie> getMoviesDataFromJson(String jsonStr) throws JSONException {
JSONObject movieJson = new JSONObject(jsonStr);
JSONArray movieArray = movieJson.getJSONArray("results");
List<Movie> results = new ArrayList<>();
for(int i = 0; i < movieArray.length(); i++) {
JSONObject movie = movieArray.getJSONObject(i);
Movie movieModel = new Movie(movie); // basically Movie has already the fields to fill (image,
// description, rating, etc) and this adds those values from the JSONObject
results.add(movieModel); // it does this one object at the time, for the lenght of the array
}
return results;
}
#Override
protected void onPostExecute(List<Movie> mv) {
if (mv != null) {
if (movieGridAdapter != null) {
movieGridAdapter.clear();
for (Movie movie : mv) {
movieGridAdapter.add(movie);
}
}
movies = new ArrayList<>();
movies.addAll(mv);
}
}
}

addOnScrollListener, pass base and limit

I am learning how to use onscrolllistner
The RecyclerOkHttpHandler class will execute a select with base 0 and limit 5 from server. what I want is to execute again the RecyclerOkHttpHandler to get the new data , for examle base 5 limit 10. but when adding the below on onscrolllistner
handler.execute().get();
i got this error :
Cannot execute task: the task has already been executed (a task can be executed only once)
ok i understand i cannot execute again the task , but how should i passe base and limit ?
this (it is working) will execute a class that will get images from server, however I need to pass base 0 and limit 5
final RecyclerOkHttpHandler handler = new RecyclerOkHttpHandler( this, new RecyclerOkHttpHandler.MyInterface() {
#Override
public void myMethod(ArrayList result) {
mAdapter_first = new MyAdapter(result,SearchActivity.this);
mAdapter_first.notifyDataSetChanged();
mRecyclerView_first.setAdapter(mAdapter_first);
}
},"girls",base,limit);
try {
handler.execute().get();
} catch (Exception e) {
Log.d("SearchActivity error", "error in mRecyclerView_first");
e.printStackTrace();
}
and this is the addOnScrollListener,
mRecyclerView_first.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
visibleItemCount = mRecyclerView_first.getChildCount();
totalItemCount = mLayoutManager.getItemCount();
firstVisibleItem = mLayoutManager.findFirstVisibleItemPosition();
if (loading) {
if (totalItemCount > previousTotal) {
loading = false;
previousTotal = totalItemCount;
System.out.println("previousTotal:" + previousTotal);
System.out.println("totalItemCount:" + totalItemCount);
System.out.println("visibleItemCount:" + visibleItemCount);
}
}
if (!loading && (totalItemCount - visibleItemCount)
<= (firstVisibleItem + visibleThreshold)) {
// End has been reached
System.out.println(totalItemCount);
Log.i("Yaeye!", "end called");
// base =String.valueOf(firstVisibleItem);
// limit=String.valueOf(visibleItemCount);
// Do something
try {
handler.execute().get();
} catch (Exception e) {
Log.d("SearchActivity error", "error in mRecyclerView_first");
e.printStackTrace();
}
loading = true;
}
}
});
this is the class RecyclerOkHttpHandler
public class RecyclerOkHttpHandler extends AsyncTask<String, Void, String> {
private Context mContext;
private MyInterface mListener;
public String category;
public String basestart;
public String limitend;
public RecyclerOkHttpHandler(Context context, MyInterface mListener, String categ, String base, String limit){
mContext = context;
this.mListener = mListener;
category=categ;
basestart=base;
limitend=limit;
}
public interface MyInterface {
public void myMethod(ArrayList result);
}
private final String Fetch_URL = "http://justedhak.com/old-files/Recyclerview_data.php";
// ArrayList<Listitem> Listitem;
ArrayList<CategoryList> Listitem;
int resulta;
OkHttpClient httpClient = new OkHttpClient();
ListView list;
String myJSON;
JSONArray peoples = null;
InputStream inputStream = null;
#Override
protected String doInBackground(String... params) {
Log.d("okhttp Fetch_URL", Fetch_URL);
RequestBody formBody = new FormEncodingBuilder()
.add("category", category)
.add("base", basestart)
.add("limit", limitend)
.build();
Request request = new Request.Builder()
.url(Fetch_URL)
.post(formBody)
.build();
String result = null;
try {
Response response = httpClient.newCall(request).execute();
if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);
inputStream = response.body().byteStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
}
result = sb.toString();
resulta = 1; //"Success
// return response.body().bytes();
} catch (Exception e) {
Toast.makeText(mContext, "Connection failed, check your connection",
Toast.LENGTH_LONG).show();
e.printStackTrace(); }
finally {
try{if(inputStream != null)inputStream.close();}catch(Exception squish){}
}
return result;
}
#Override
protected void onPostExecute(String result){
if( resulta ==1){
myJSON=result;
Log.e("result",result);
showList();
}
else{
Log.e("d","there is an error on postexecute in okhhttphandler.java");
}
}
protected void showList(){
try {
JSONObject jsonObj = new JSONObject(myJSON);
peoples = jsonObj.getJSONArray("result");
System.out.println("Length:"+peoples.length());
int J_length=peoples.length()-1;
//JSONObject maxj = peoples.getJSONObject(peoples.length() - 1);
// max of arrray
jsonObj= peoples.getJSONObject(J_length);
String j_id= jsonObj.getString("id");
int _id = Integer.parseInt(j_id);
System.out.println(j_id);
//max of
DatabaseHandler db = new DatabaseHandler(mContext);
String db_id="";
db_id = db.getmax();
if (db_id== null)
{
db_id="0";
}
int d_id = Integer.parseInt(db_id);
Log.e("db_id", db_id);
Log.e("j_id",j_id);
// if (_id < d_id) {
System.out.println("Getting json result ");
Listitem = new ArrayList<CategoryList>();
for (int i = 0; i < peoples.length(); i++) {
JSONObject c = peoples.getJSONObject(i);
String id = c.getString("id");
String url = c.getString("url");
Listitem.add(new CategoryList(id, url));
}
if (mListener != null)
mListener.myMethod(Listitem);
} catch (JSONException e) {
e.printStackTrace();
}
}
}

I read your problem again, and the solution might just be to create a new RecyclerOkHttpHandler each time. That's what the error message says and that's how AsyncTasks work. If you call .execute() once you cannot call it again, you have to create a new object.
Still you should override onPostExecute() else you are blocking the UI thread. Have a look at AsyncTask.
I need the code for RecyclerOkHttpHandler to say more...

Count number of elements in a JSON Array, and display the result on Textview - Android

I want to count the number of elements I am getting through the JSON array, and display it over the TextView using .settext() method.
I am getting the following JSON ARRAY :
{
"result":
[
{
"id":"283",
"fullname":"shyam",
"contactno":"898888888",
"collegename":"mjc",
"emailaddress":"shyamzawar",
"eventname":"gaming"
},
{
"id":"285",
"fullname":"ffca",
"contactno":"8888888888",
"collegename":"Brihan maharashtra College of Commerce (BMCC)",
"emailaddress":"shyamzawar#ymail.com",
"eventname":"FootBall"
}
]
}
Below is my activity :
private static final String TAG = "userList";
private List<FeedItem> feedsList;
private RecyclerView mRecyclerView;
private MyRecyclerAdapter adapter;
private ProgressBar progressBar;
private TextView ParticipantsCounts;
int count=0;
private SwipeRefreshLayout swipeRefreshLayout;
private final String url="http://bmcctroika.hol.es/get-data.php";;
private int offSet = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_admin);
// Initialize recycler view
mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
progressBar = (ProgressBar) findViewById(R.id.progress_bar);
progressBar.setVisibility(View.VISIBLE);
ParticipantsCounts= (TextView) findViewById(R.id.ParticipantsCount);
// Downloading data from below url
new AsyncHttpTask().execute(url);
swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh_layout);
swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
refreshitems();
}
});
}
private void refreshitems() {
new AsyncHttpTask().execute(url);
}
#Override
public void onRefresh() {
new AsyncHttpTask().execute(url);
}
public class AsyncHttpTask extends AsyncTask<String, Void, Integer> {
#Override
protected void onPreExecute() {
setProgressBarIndeterminateVisibility(true);
}
#Override
protected Integer doInBackground(String... params) {
Integer result = 0;
HttpURLConnection urlConnection;
try {
URL url = new URL(params[0]);
urlConnection = (HttpURLConnection) url.openConnection();
int statusCode = urlConnection.getResponseCode();
// 200 represents HTTP OK
if (statusCode == 200)
{
BufferedReader r = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
StringBuilder response = new StringBuilder();
String line;
while ((line = r.readLine()) != null)
{
response.append(line);
}
parseResult(response.toString());
result = 1; // Successful
} else {
result = 0; //"Failed to fetch data!";
}
} catch (Exception e) {
Log.d(TAG, e.getLocalizedMessage());
}
return result; //"Failed to fetch data!";
}
#Override
protected void onPostExecute(Integer result)
{
// Download complete.
progressBar.setVisibility(View.GONE);
if (result == 1)
{
adapter = new MyRecyclerAdapter(AdminActivity.this, feedsList);
mRecyclerView.setAdapter(adapter);
} else
{
Toast.makeText(AdminActivity.this, "Failed to fetch data!", Toast.LENGTH_SHORT).show();
}
swipeRefreshLayout.setRefreshing(false);
}
}
private void parseResult(String result) {
try {
JSONObject response = new JSONObject(result);
JSONArray posts = response.optJSONArray("result");
feedsList = new ArrayList<>();
for (int i = 0; i < posts.length(); i++) {
JSONObject post = posts.optJSONObject(i);
FeedItem item = new FeedItem();
item.setTitle(post.optString("fullname"));
item.setContact(post.optString("contactno"));
item.setEmail(post.optString("emailaddress"));
item.setEventname(post.optString("eventname"));
item.setCollegename(post.optString("collegename"));
feedsList.add(item);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}

You need to get the lenght of the result JSONArray. So in your code, you can get the length of posts -- JSONArray posts = response.optJSONArray("result");.
This will give you the number of items in the result array:
private void parseResult(String result) {
try {
JSONObject response = new JSONObject(result);
JSONArray posts = response.optJSONArray("result");
int number = posts.length();
//then to set it to the text view:
ParticipantsCounts.setText(String.valueOf(number));
//the rest of your code ...
feedsList = new ArrayList<>();
for (int i = 0; i < posts.length(); i++) {
JSONObject post = posts.optJSONObject(i);
FeedItem item = new FeedItem();
item.setTitle(post.optString("fullname"));
item.setContact(post.optString("contactno"));
item.setEmail(post.optString("emailaddress"));
item.setEventname(post.optString("eventname"));
item.setCollegename(post.optString("collegename"));
feedsList.add(item);
}
} catch (JSONException e) {
e.printStackTrace();
}
}

Identical Fragments - one works, one doesn't

I have two fragments each being inflated from a sliding menu. One fragment works as expected, the other one force closes the app. The Fragments are identical, except in name. the second has a runtime, fatal exception main in the log.
Here is the Fragment(s):
public class FeedZFragment extends Fragment {
private static final String TAG = "RecyclerViewExample";
private List<FeedZ> feedItemList = new ArrayList<FeedZ>();
//added static might remove
private static RecyclerView mRecyclerView;
private static MyRecyclerAdapterZ adapter;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate( R.layout.fragment_recyclerview, container, false);
/* Allow activity to show indeterminate progress-bar */
getActivity().requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
/* Initialize recycler view */
mRecyclerView = (RecyclerView) getActivity().findViewById(R.id.my_recycler_view);
mRecyclerView.setLayoutManager(new GridLayoutManager(getActivity(),2));
/*Downloading data from below url*/
final String url = "http://www.thisismysite.com/a.json";
new AsyncHttpTask().execute(url);
return rootView;
}
public class AsyncHttpTask extends AsyncTask<String, Void, Integer> {
/* #Override
protected void onPreExecute() {
setProgressBarIndeterminateVisibility(true);
}*/
#Override
protected Integer doInBackground(String... params) {
InputStream inputStream = null;
Integer result = 0;
HttpURLConnection urlConnection = null;
try {
/* forming th java.net.URL object */
URL url = new URL(params[0]);
urlConnection = (HttpURLConnection) url.openConnection();
/* for Get request */
urlConnection.setRequestMethod("GET");
int statusCode = urlConnection.getResponseCode();
/* 200 represents HTTP OK */
if (statusCode == 200) {
BufferedReader r = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
StringBuilder response = new StringBuilder();
String line;
while ((line = r.readLine()) != null) {
response.append(line);
}
parseResult(response.toString());
result = 1; // Successful
}else{
result = 0; //"Failed to fetch data!";
}
} catch (Exception e) {
Log.d(TAG, e.getLocalizedMessage());
}
return result; //"Failed to fetch data!";
}
#Override
protected void onPostExecute(Integer result) {
// setProgressBarIndeterminateVisibility(false);
/* Download complete. Lets update UI */
if (result == 1) {
adapter = new MyRecyclerAdapterZ(getActivity(), feedItemList);
mRecyclerView.setAdapter(adapter);
} else {
Log.e(TAG, "Failed to fetch data!");
}
}
}
private void parseResult(String result) {
try {
JSONObject response = new JSONObject(result);
JSONArray products = response.optJSONArray("products");
/*Initialize array if null*/
if (null == feedItemList) {
feedItemList = new ArrayList<FeedZ>();
}
for (int i = 0; i < products.length(); i++) {
JSONObject product = products.optJSONObject(i);
FeedZ item = new FeedZ();
item.setTitle(product.optString("title"));
item.setImage_url(product.optString("image_url"));
item.setPackage_url(product.optString("package_url"));
item.setIds(product.optString("ids"));
feedItemList.add(item);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
the error is:
java.lang.NullPointerException
at com.nmthemes.WallFragment.onCreateView(WallFragment.java:44)
SOLUTION:
they weren't exactly identical.
getActivity().findViewById(R.id.my_recycler_view); should have been:
rootView.findViewById(R.id.my_recycler_view);
I changed it in one, not the other.