please I am trying to post data from JSON in my recyclerview. I am using the AsyncTaskLoader but nothing just shows on the screen. I have logged the data I need from JSON, to confirm I got the parsing right, and they show up. I have also logged the array of objects that are meant to be displayed, and they also show in the logcat, it is just the screen of my app that doesn't show any data. I am using a view pager with 2 fragments and this issue is the same for both. Here is my FragmentActivity, I will post just one since issue is the same
public class TechNewsFragment extends Fragment {
private SwipeRefreshLayout mSwipeRefreshLayout;
private TextView mErrorMessage;
private NewsAdapter mNewsAdapter;
ArrayList<News> news;
NetworkInfo info;
// The Loader takes in a bundle
Bundle sourceBundle = new Bundle();
private final String LOG_TAG = MainActivity.class.getSimpleName();
private static final String TECH_NEWS_QUERY_URL = "query";
private static final String TECH_NEWS_SOURCE = "techcrunch";
private static final int TECH_NEWS_LOADER = 22;
private RecyclerView mRecyclerView;
public TechNewsFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_news, container, false);
mErrorMessage = (TextView) view.findViewById(R.id.tv_error_message);
mRecyclerView = (RecyclerView) view.findViewById(R.id.recycler_view_main);
mSwipeRefreshLayout = (SwipeRefreshLayout) view.findViewById(R.id.swipeRefresh);
mRecyclerView.setLayoutManager(new LinearLayoutManager(getContext(), LinearLayoutManager.VERTICAL, false));
getActivity().getSupportLoaderManager().initLoader(TECH_NEWS_LOADER, null, new NewsDataLoader());
mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
Log.v(LOG_TAG, "Refreshing");
restartLoader();
mSwipeRefreshLayout.setColorSchemeResources(
R.color.colorPrimary,
R.color.colorPrimaryDark);
}
});
return view;
}
private boolean isConnected(){
ConnectivityManager cm = (ConnectivityManager) getActivity()
.getSystemService(CONNECTIVITY_SERVICE);
info = cm.getActiveNetworkInfo();
return info != null && info.isConnectedOrConnecting();
}
private int anyRandomInt(Random random) {
return random.nextInt();
}
private void restartLoader() {
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
URL techNewsUrl = TechNetworkUtils.buildUrl(TECH_NEWS_SOURCE);
sourceBundle.putString(TECH_NEWS_QUERY_URL, techNewsUrl.toString());
Random random = new Random();
int uniqueId = anyRandomInt(random); //Generates a new ID for each loader call;
// sourceBundle.putString("query", s);]
LoaderManager loaderManager = getActivity().getSupportLoaderManager();
if (loaderManager.getLoader(TECH_NEWS_LOADER) == null) {
loaderManager.initLoader(uniqueId, sourceBundle, new NewsDataLoader());
} else {
loaderManager.restartLoader(TECH_NEWS_LOADER, sourceBundle, new
NewsDataLoader());
}
}
}, 5000);
mSwipeRefreshLayout.setRefreshing(false);
Log.v(LOG_TAG, "Finished refreshing");
}
private void showErrorScreen(){
mErrorMessage.setVisibility(View.VISIBLE);
mRecyclerView.setVisibility(View.INVISIBLE);
mErrorMessage.setText(getString(R.string.internet_error));
}
`public class NewsDataLoader implements LoaderManager.LoaderCallbacks<ArrayList<News>> {
@Override
public Loader<ArrayList<News>> onCreateLoader(int id, final Bundle args) {
if (isConnected()){
mErrorMessage.setVisibility(View.INVISIBLE);
mRecyclerView.setVisibility(View.VISIBLE);
return new AsyncTaskLoader<ArrayList<News>>(getActivity()) {
ArrayList<News> mNewsData;
@Override
protected void onStartLoading() {
super.onStartLoading();
if (mNewsData != null){
deliverResult(mNewsData);
}else{
forceLoad();
mSwipeRefreshLayout.setRefreshing(true);
}
}
@Override
public ArrayList<News> loadInBackground() {
try {
ArrayList<News> news = TechNetworkUtils.parseJSON(TECH_NEWS_SOURCE);
return news;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
public void deliverResult(ArrayList<News> data) {
mNewsData = data;
super.deliverResult(data);
}
};
}else{
showErrorScreen();
return null;
}
}
@Override
public void onLoadFinished(Loader<ArrayList<News>> loader, ArrayList<News> data) {
mSwipeRefreshLayout.setRefreshing(false);
if (null == data) {
showErrorScreen();
} else {
mErrorMessage.setVisibility(View.INVISIBLE);
mRecyclerView.setVisibility(View.VISIBLE);
if (news != null) {
// news.clear();
news.addAll(data);
mNewsAdapter = new NewsAdapter(news);
mRecyclerView.setAdapter(mNewsAdapter);
mNewsAdapter.notifyDataSetChanged();
} else {
news = data;
}
Log.i(LOG_TAG + " this is the data", data.toString());
// Array of objects shows in the log
}
}
@Override
public void onLoaderReset(Loader<ArrayList<News>> loader) {
// loader.forceLoad();
}
}
}`
This is my adapter class
public class NewsAdapter extends
RecyclerView.Adapter<NewsAdapter.NewsHolder> {
// Variable used to reference the model
private ArrayList<News> mNews = new ArrayList<>();
// NewsHolder class that extends the ViewHolder
public static class NewsHolder extends RecyclerView.ViewHolder{
private TextView mNewsTextView;
private TextView mTimeStampTextView;
// Constructor to set the views
public NewsHolder(View itemView){
super(itemView);
mNewsTextView = (TextView) itemView.findViewById(R.id.news_tv);
mTimeStampTextView = (TextView) itemView.findViewById(R.id.time_tv);
}
}
// Constructor to set the adapter
public NewsAdapter(ArrayList<News> news){
mNews = news;
}
@Override
public NewsHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view =
LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_view,
parent, false);
return new NewsHolder(view);
}
@Override
public void onBindViewHolder(NewsHolder holder, int position) {
holder.mNewsTextView.setText(mNews.get(position).getNews());
holder.mTimeStampTextView.setText(mNews.get(position).getTime());
}
@Override
public int getItemCount() {
return mNews.size();
}
}`
This is class to parse JSON and handle network connectivity
public class TechNetworkUtils {
private static final String LOG_TAG = MainActivity.class.getSimpleName();
public static ArrayList<News> parseJSON(String source) throws IOException {
URL url = buildUrl(source);
String jsonResult = getResponseFromHttpUrl(url);
ArrayList<News> news = new ArrayList<>();
try{
JSONObject jsonObject = new JSONObject(jsonResult);
JSONArray jsonArray = jsonObject.getJSONArray("articles");
if (jsonArray != null){
for (int i = 0; i < jsonArray.length(); i++){
JSONObject article = jsonArray.getJSONObject(i);
String title = article.getString("title");
String time = article.getString("publishedAt");
news.add(new News(title, time));
Log.i(LOG_TAG, title);
Log.i(LOG_TAG, time);
}
}
}catch (JSONException | NullPointerException e){
e.printStackTrace();
return null;
}
return news;
}
public static URL buildUrl(String techNewsSource){
final String TECH_NEWS_BASE_URL = "https://newsapi.org/v1/articles";
final String PARAM_SOURCE = "source";
final String PARAM_SORT_BY = "sortBy";
final String latest = "latest";
final String PARAM_API_KEY = "apiKey";
final String KEY = "3431d57e51a04c1d967e2eb96c99fd1a";
Uri builtUri = Uri.parse(TECH_NEWS_BASE_URL).buildUpon()
.appendQueryParameter(PARAM_SOURCE, techNewsSource)
.appendQueryParameter(PARAM_SORT_BY, latest)
.appendQueryParameter(PARAM_API_KEY, KEY)
.build();
Log.i(LOG_TAG, builtUri.toString());
URL url = null;
try{
url = new URL(builtUri.toString());
}catch (MalformedURLException e){
e.printStackTrace();
}
return url;
}
public static String getResponseFromHttpUrl(URL url) throws IOException{
HttpURLConnection urlConnection = null;
String newsJsonStr = null;
BufferedReader reader = null;
try{
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setReadTimeout(15000);
urlConnection.setConnectTimeout(10000);
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(false);
urlConnection.setDoInput(true);
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){
buffer.append(line + "\n");
}
if (buffer.length() == 0){
return null;
}
newsJsonStr = buffer.toString();
}catch(IOException e){
Log.e(LOG_TAG, "Error fetching data", e);
return null;
}finally{
if (urlConnection != null){
urlConnection.disconnect();
}
if (reader != null){
try{
reader.close();
}catch (IOException e){
Log.e(LOG_TAG, "Error closing stream", e);
}
}
}
return newsJsonStr;
}
}
This is my pojo class
public class News {
private String mNews;
private String mTime;
public News(String news, String time){
mNews = news;
mTime = time;
}
public String getNews() {
return mNews;
}
public String getTime() {
return mTime;
}
}`
This is my list_item_layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/title_frame">
<TextView
android:padding="16dp"
android:layout_width="match_parent"
android:layout_height="64dp"
android:id="@+id/news_tv"
tools:text="Get exciting news here"/>
</FrameLayout>
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end">
<TextView
android:id="@+id/time_tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="8dp"
android:paddingRight="16dp"
tools:text="12:00pm"/>
</FrameLayout>
</LinearLayout>
This is my log.i
/* 06-06 21:35:25.834 1092-1092/com.ire.blogbot E/dalvikvm: Could not
find
class 'android.graphics.drawable.RippleDrawable', referenced from method
android.support.v7.widget.AppCompatImageHelper.hasOverlappingRendering
06-06 21:35:25.834 1092-1092/com.ire.blogbot W/dalvikvm: VFY: unable to
resolve instanceof 146 (Landroid/graphics/drawable/RippleDrawable;) in
Landroid/support/v7/widget/AppCompatImageHelper;
06-06 21:35:25.922 1092-1106/com.ire.blogbot I/MainActivity:
https://newsapi.org/v1/articles?source=entertainment-
weekly&sortBy=top&apiKey=3431d57e51a04c1d967e2eb96c99fd1a
06-06 21:35:25.934 1092-1107/com.ire.blogbot I/MainActivity:
https://newsapi.org/v1/articles?
source=techcrunch&sortBy=latest&apiKey=3431d57e51a04c1d967e2eb96c99fd1a
06-06 21:35:26.042 1092-1092/com.ire.blogbot W/EGL_genymotion:
eglSurfaceAttrib not implemented
06-06 21:35:26.226 376-423/system_process I/ActivityManager: Displayed
com.ire.blogbot/.activity.MainActivity: +606ms
06-06 21:35:26.270 376-449/system_process I/qtaguid: Failed write_ctrl(s 0
10021) res=-1 errno=1
06-06 21:35:26.270 376-449/system_process W/NetworkManagementSocketTagger:
setKernelCountSet(10021, 0) failed with errno -1
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: How can tech
companies treat their contractors better?
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: 2017-06-
06T21:19:28Z
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: Audi is the
first to test autonomous vehicles in New York
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: 2017-06-
06T20:58:34Z
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: Bragi’s Dash
Pro is a sophisticated and smart AirPods alternative
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: 2017-06-
06T20:05:41Z
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: As the Surface
line courts creatives, Apple pushes back with the iMac and iPad Pro
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: 2017-06-
06T20:04:19Z
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: What Silicon
Valley can learn from Lebanon’s women in tech
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: 2017-06-
06T20:00:53Z
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: Matt Mitchell
of CryptoHarlem is building an open source tool to help organizations
prepare for data breaches
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: 2017-06-
06T19:29:04Z
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: Pinterest
raises $150M at a $12.3B valuation as it makes a full press into
visual search
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: 2017-06-
06T19:27:05Z
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: Tulip, the app
platform for manufacturers, picks up $13 million from NEA
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: 2017-06-
06T18:45:34Z
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: Take a look at
these first pictures of Fisker’s $130K EMotion electric car
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: 2017-06-
06T18:27:57Z
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: iOS 11 will
help you free up storage on your iPhone through personalized suggestions
06-06 21:35:27.182 1092-1107/com.ire.blogbot I/MainActivity: 2017-06-
06T18:22:33Z
06-06 21:35:27.182 1092-1092/com.ire.blogbot
I/MainActivity this is the data: [com.ire.blogbot.model.News@536e8250,
com.ire.blogbot.model.News@536e65c0, com.ire.blogbot.model.News@536d157c,
com.ire.blogbot.model.News@536e80ec, com.ire.blogbot.model.News@536e80f8,
com.ire.blogbot.model.News@536e8104, com.ire.blogbot.model.News@536e8110,
com.ire.blogbot.model.News@536e811c, com.ire.blogbot.model.News@536e8128,
com.ire.blogbot.model.News@536e8134]
06-06 21:35:27.202 1092-1106/com.ire.blogbot I/MainActivity:
{"status":"ok","source":"entertainment-weekly","sortBy":"top","articles":
[{"author":null,"title":"The Zodiac Killer: How a first-time filmmaker
attempted to catch the serial
murderer","description":null,"url":"http://zodiactruecrime.ew.com/","urlT
oImage":null,"publishedAt":null},{"author":"Maureen Lee Lenker","title":"Sam
Smith teases return to the recording studio with
new photos","description":"","url":"http://ew.com/music/2017/06/06/sam-
smith-teases-new-
album/","urlToImage":"http://i0.wp.com/ewedit.files.wordpress.com/2017/06/g
ettyimages-521740878.jpg?
crop=0px%2C82px%2C2700px%2C1418px&resize=1200%2C630&ssl=1","publishedAt":"2
017-06-06T21:22:08Z"},{"author":"Marisa Marcellino","title":"Highest-
grossing
Broadway shows of
all time","description":"","url":"http://ew.com/theater/2017/06/06/highest-
grossing-broadway-shows-of-all-
time/","urlToImage":"http://i1.wp.com/ewedit.files.wordpress.com/2017/03/li
onking.jpg?
crop=0px%2C42px%2C2700px%2C1419px&resize=1200%2C630&ssl=1","publishedAt":"2
017-06-06T19:52:02Z"},{"author":"Kyle Fowle","title":"'House of Cards'
Recap:
How Far Is Claire Willing to Go to Secure the
Presidency?","description":"With threats forming all around them, Frank and
Claire take violent action to secure their
legacy","url":"http://ew.com/recap/house-of-cards-season-5-episode-
12/","urlToImage":"http://i0.wp.com/ewedit.files.wordpress.com/2017/06/hoc_
512_unit_01846r.jpg?
crop=3px%2C105px%2C2699px%2C1418px&resize=1200%2C630&ssl=1","publishedAt":"
2017-06-06T19:49:12Z"},{"author":"Nivea Serrao","title":"Selena Gomez
responds
to ’13 Reasons Why’ controversy","description":"'This is happening every
day'","url":"http://ew.com/tv/2017/06/06/selena-gomez-13-reasons-why-
controversy-
2/","urlToImage":"http://i1.wp.com/ewedit.files.wordpress.com/2017/04/13rw_
113_01153r.jpg?
crop=0px%2C53px%2C2700px%2C1418px&resize=1200%2C630&ssl=1","publishedAt":"2
017-06-06T19:45:59Z"},{"author":"Ruth Kinane","title":"‘Hollywood Game
Night’
teaser: ‘This Is Us,’ ‘Veep,’ ‘Walking Dead’ casts ready
for battle","description":"Jane Lynch returns to
host","url":"http://ew.com/tv/2017/06/06/hollywood-game-night-teaser-this-
is-us-veep-walking-dead-
casts/","urlToImage":"http://i1.wp.com/ewedit.files.wordpress.com/2017/06/h
ollywoodgame.jpg?
crop=0px%2C21px%2C2700px%2C1419px&resize=1200%2C630&ssl=1","publishedAt":"2
017-06-06T19:30:49Z"},{"author":"Joey Nolfi","title":"Watch Jerry Seinfeld
refuse a hug from Kesha","description":"\"I don't know who that was... I
wish her the best,\" the 63-year-old
said","url":"http://ew.com/news/2017/06/06/jerry-seinfeld-kesha-
hug/","urlToImage":"http://i0.wp.com/ewedit.files.wordpress.com/2017/06/sei
nfeldkesha.jpg?
crop=0px%2C13px%2C3200px%2C1681px&resize=1200%2C630&ssl=1","publishedAt":"2
017-06-06T19:05:57Z"},{"author":"Maureen Lee Lenker","title":"Tonys 2017:
Watch
performances from this year’s Best
Musical nominees","description":"","url":"http://ew.com/theater/2017/06/06/
tonys-2017-nominations-best-musical-
performances/","urlToImage":"http://i2.wp.com/ewedit.files.wordpress.com/20
17/0
6/deh-ben-platt-4449-photo.jpg?
crop=0px%2C382px%2C2700px%2C1419px&resize=1200%2C630&ssl=1","publishedAt":"
2017
-06-06T19:00:59Z"},{"author":"Ray Rahman","title":"‘Broad City’ returns
under a ‘cloud of doom,’ stars tease","description":"Plus: RuPaul makes a
'f---ing titillating' and 'godlike'
cameo","url":"http://ew.com/tv/2017/06/06/broad-city-season-4-
winter/","urlToImage":"http://i2.wp.com/ewedit.files.wordpress.com/2017/06/
broadcity.jpg?
crop=0px%2C87px%2C2700px%2C1419px&resize=1200%2C630&ssl=1","publishedAt":"2
017-06-06T18:56:12Z"},{"author":"Nivea Serrao","title":"How ‘The Moth’
podcast
turned storytelling into a
worldwide movement","description":"","url":"http://ew.com/podcasts/2017/06/
06/the-moth-podcast-20th-
anniversary/","urlToImage":"http://i1.wp.com/ewedit.files.wordpress.com/201
7/06/gettyimages-530299778.jpg?
crop=0px%2C18px%2C1800px%2C945px&resize=1200%2C630","publishedAt":"2017-
06-06T18:48:15Z"}]}
06-06 21:35:33.406 376-386/system_process I/ActivityManager: No longer want
com.android.exchange (pid 870): hidden #16
06-06 21:41:36.890 55-55/? W/Genyd: Can't parse request
06-06 21:41:36.958 376-466/system_process I/ClipboardService: Got clipboard
for user=0
06-06 21:41:36.958 376-466/system_process I/ClipboardService: Got clipboard
for user=0
06-06 21:41:36.958 376-389/system_process I/ClipboardService: Got clipboard
for user=0
06-06 21:41:36.958 376-389/system_process I/ClipboardService: Got clipboard
for user=0
06-06 21:41:36.958 376-389/system_process I/ClipboardService: Got clipboard
for user=0
06-06 21:41:37.158 376-466/system_process I/ClipboardService: Got clipboard
for user=0
06-06 21:41:37.158 376-466/system_process I/ClipboardService: Got clipboard
for user=0
06-06 21:41:37.162 376-389/system_process I/ClipboardService: Got clipboard
for user=0
06-06 21:41:37.162 376-389/system_process I/ClipboardService: Got clipboard
for user=0
06-06 21:41:37.162 376-389/system_process I/ClipboardService: Got clipboard
for user=0
I need the data to display automatically when the app is launched and refresh when onSwipeRefreshLayout is called.
