Develop Reference

Card View not appearing in RecyclerView

I'm building an app that connects to a REST API and retrieves all the Employees in a Database. The app uses a RecyclerView to display all the Employees that are brought back in a CardView. The problem is nothing appears in the RecyclerView, and there is data that is being returned from the REST API.
It is an Android application, built in Java, using Pie for the OS. The project was created using the Basic Activity Template.
My Activity Class
public class ViewAllEmployees extends AppCompatActivity {
private List<Employee> employees;
private RecyclerView rcView;
private EmployeeAdapter adapter;
private Context context;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_all_employees);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
context = this;
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
FetchEmployeesTask async = new FetchEmployeesTask(new AsyncResponse() {
#Override
public void processFinished(List<Employee> output) {
Log.i("Async", "Finished");
}
});
async.execute();
rcView = findViewById(R.id.rcView);
adapter = new EmployeeAdapter(context, employees);
rcView.setAdapter(adapter);
rcView.setLayoutManager(new LinearLayoutManager(context));
}
private class FetchEmployeesTask extends AsyncTask<Void, Void, List<Employee>> {
public AsyncResponse delegate = null;
public FetchEmployeesTask(AsyncResponse asyncResponse){
delegate = asyncResponse;
}
#Override
protected List<Employee> doInBackground(Void... voids) {
return new APIHelper().fetchItems();
}
#Override
protected void onPostExecute(List<Employee> items) {
employees = items;
delegate.processFinished(items);
}
}
public interface AsyncResponse{
void processFinished(List<Employee> output);
}
}
The Employee Adapter for the RecyclerView
public class EmployeeAdapter extends RecyclerView.Adapter<EmployeeAdapter.EmployeeViewHolder> {
private List<Employee> employees;
private final LayoutInflater mInflater;
private Context context;
public int position;
public EmployeeAdapter(Context context, List<Employee> employeeList){
this.context = context;
employees = new ArrayList<>();
mInflater = LayoutInflater.from(context);
employees = employeeList;
}
#NonNull
#Override
public EmployeeViewHolder onCreateViewHolder(#NonNull ViewGroup viewGroup, int i) {
View mItemView = mInflater.inflate(R.layout.employee_card, viewGroup, false);
return new EmployeeViewHolder(mItemView, this);
}
#Override
public void onBindViewHolder(#NonNull EmployeeViewHolder employeeViewHolder, int i) {
Employee empl = employees.get(i);
employeeViewHolder.name.setText(empl.firstName + empl.lastName);
employeeViewHolder.department.setText(empl.department);
}
#Override
public int getItemCount() {
return employees == null ? 0 : employees.size();
}
class EmployeeViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public final TextView name;
public final TextView department;
private EmployeeAdapter adapter;
private final CardView card;
public EmployeeViewHolder(View itemView, EmployeeAdapter adapter) {
super(itemView);
name = itemView.findViewById(R.id.txtName);
department = itemView.findViewById(R.id.txtDepartment);
card = itemView.findViewById(R.id.cv);
itemView.setOnClickListener(this);
this.adapter = adapter;
}
#Override
public void onClick(View view) {
}
}
}
The APIHelper class
public class APIHelper {
private static final String ENDPOINT = "ENDPOINTADDRESS";
private static final String TAG = "APIHelper";
public byte[] getUrlBytes(String urlSpec) throws IOException{
URL url = new URL(urlSpec);
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
try{
ByteArrayOutputStream out = new ByteArrayOutputStream();
InputStream in = connection.getInputStream();
if(connection.getResponseCode() != HttpURLConnection.HTTP_OK){
return null;
}
int bytesRead = 0;
byte[] buffer = new byte[1024];
while((bytesRead = in.read(buffer)) > 0){
out.write(buffer, 0, bytesRead);
}
out.close();
return out.toByteArray();
}
finally {
connection.disconnect();
}
}
public String getUrlString(String urlSpec) throws IOException{
return new String((getUrlBytes(urlSpec)));
}
private void parseItems(List<Employee> employees, JSONArray jsonBody) throws IOException, JSONException {
JSONArray employeeArray = jsonBody;
for(int i = 0; i < employeeArray.length(); i++){
JSONObject jsonEmployee = employeeArray.getJSONObject(i);
JSONObject job = jsonEmployee.getJSONObject("Job");
Employee emp = new Employee();
//emp.setDepartment(jsonEmployee.getString("DepartmentId"));
emp.setEmail(jsonEmployee.getString("EmailAddress"));
emp.setEmployeeID(jsonEmployee.getString("EmployeeID"));
emp.setFirstName(jsonEmployee.getString("FirstName"));
emp.setLastName(jsonEmployee.getString("LastName"));
emp.setMiddleInitial(jsonEmployee.getString("MiddleInitial"));
emp.setPosition(job.getString("JobTitle"));
emp.setWorkNumber(jsonEmployee.getString("WorkNumber"));
employees.add(emp);
}
}
public List<Employee> fetchItems(){
List<Employee> employees = new ArrayList<>();
try{
String url = Uri.parse(ENDPOINT).buildUpon().build().toString();
String jsonString = getUrlString(url);
Log.i(TAG, "Received JSON: " + jsonString);
JSONArray jsonBody = new JSONArray(jsonString);
parseItems(employees, jsonBody);
}
catch (IOException ioe){
Log.e(TAG, "Failed to fetch items", ioe);
}
catch (JSONException je){
Log.e(TAG, "Failed to parse json:", je);
}
return employees;
}
The Layout for ViewAllEmployees
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context=".ViewAllEmployees"
tools:showIn="#layout/activity_view_all_employees">
<android.support.v7.widget.RecyclerView
android:id="#+id/rcView"
android:layout_width="395dp"
android:layout_height="659dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
The Card View that is in the Recyclerview
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:padding="16dp">
<android.support.v7.widget.CardView
android:id="#+id/cv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
app:cardElevation="5dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/txtName"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Name"/>
<TextView
android:id="#+id/txtDepartment"
android:layout_width="match_parent"
android:layout_height="127dp"
android:layout_below="#+id/txtName"
android:layout_alignEnd="#+id/txtName"
android:layout_marginTop="-142dp"
android:layout_marginEnd="0dp" />
</RelativeLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
When the App is run, the RecyclerView should populate with CardViews that display an Employees name and their Department. However, it currently displays nothing.

You have to notify your adapter after populating your array list. Initialize your employee array list variable,then Do:
private class FetchEmployeesTask extends AsyncTask<Void, Void, List<Employee>> {
public AsyncResponse delegate = null;
public FetchEmployeesTask(AsyncResponse asyncResponse){
delegate = asyncResponse;
}
#Override
protected List<Employee> doInBackground(Void... voids) {
return new APIHelper().fetchItems();
}
#Override
protected void onPostExecute(List<Employee> items) {
employees.addAll(items);
adapter.notifyDataSetChanged();
delegate.processFinished(items);
}
}

FetchEmployeesTask async = new FetchEmployeesTask(new AsyncResponse() {
#Override
public void processFinished(List<Employee> output) {
Log.i("Async", "Finished");
employees.addAll(items);
adapter.notifyDataSetChanged();
}
});

ListView not displayed in Fragment (Android)

So im following this tutorial http://www.wingnity.com/blog/android-json-parsing-and-image-loading-tutorial/ on how to parse a JSON Api and displays data into Listview
I tried to adapt the code in my fragment , in onCreateView method , but the Listview is not displayed (blank fragment). And i dont know why.
I imported all the required libs
Actor.java
public class Actors {
private String name;
private String description;
private String dob;
private String country;
private String height;
private String spouse;
private String children;
private String image;
public Actors() {
// TODO Auto-generated constructor stub
}
public Actors(String name, String description, String dob, String country,
String height, String spouse, String children, String image) {
super();
this.name = name;
this.description = description;
this.dob = dob;
this.country = country;
this.height = height;
this.spouse = spouse;
this.children = children;
this.image = image;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getDob() {
return dob;
}
public void setDob(String dob) {
this.dob = dob;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public String getHeight() {
return height;
}
public void setHeight(String height) {
this.height = height;
}
public String getSpouse() {
return spouse;
}
public void setSpouse(String spouse) {
this.spouse = spouse;
}
public String getChildren() {
return children;
}
public void setChildren(String children) {
this.children = children;
}
public String getImage() {
return image;
}
public void setImage(String image) {
this.image = image;
}
}
ActorAdapter.java
import java.io.InputStream;
import java.util.ArrayList;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import info.androidhive.navigationdrawer.R;
public class ActorAdapter extends ArrayAdapter<Actors> {
ArrayList<Actors> actorList;
LayoutInflater vi;
int Resource;
ViewHolder holder;
public ActorAdapter(Context context, int resource, ArrayList<Actors> objects) {
super(context, resource, objects);
vi = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
Resource = resource;
actorList = objects;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
// convert view = design
View v = convertView;
if (v == null) {
holder = new ViewHolder();
v = vi.inflate(Resource, null);
holder.imageview = (ImageView) v.findViewById(R.id.ivImage);
holder.tvName = (TextView) v.findViewById(R.id.tvName);
holder.tvDescription = (TextView) v.findViewById(R.id.tvDescriptionn);
holder.tvDOB = (TextView) v.findViewById(R.id.tvDateOfBirth);
holder.tvCountry = (TextView) v.findViewById(R.id.tvCountry);
holder.tvHeight = (TextView) v.findViewById(R.id.tvHeight);
holder.tvSpouse = (TextView) v.findViewById(R.id.tvSpouse);
holder.tvChildren = (TextView) v.findViewById(R.id.tvChildren);
v.setTag(holder);
} else {
holder = (ViewHolder) v.getTag();
}
holder.imageview.setImageResource(R.drawable.imgadd);
new DownloadImageTask(holder.imageview).execute(actorList.get(position).getImage());
holder.tvName.setText(actorList.get(position).getName());
holder.tvDescription.setText(actorList.get(position).getDescription());
holder.tvDOB.setText("B'day: " + actorList.get(position).getDob());
holder.tvCountry.setText(actorList.get(position).getCountry());
holder.tvHeight.setText("Height: " + actorList.get(position).getHeight());
holder.tvSpouse.setText("Spouse: " + actorList.get(position).getSpouse());
holder.tvChildren.setText("Children: " + actorList.get(position).getChildren());
return v;
}
static class ViewHolder {
public ImageView imageview;
public TextView tvName;
public TextView tvDescription;
public TextView tvDOB;
public TextView tvCountry;
public TextView tvHeight;
public TextView tvSpouse;
public TextView tvChildren;
}
private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
ImageView bmImage;
public DownloadImageTask(ImageView bmImage) {
this.bmImage = bmImage;
}
protected Bitmap doInBackground(String... urls) {
String urldisplay = urls[0];
Bitmap mIcon11 = null;
try {
InputStream in = new java.net.URL(urldisplay).openStream();
mIcon11 = BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return mIcon11;
}
protected void onPostExecute(Bitmap result) {
bmImage.setImageBitmap(result);
}
}
}
Articles.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="4dp"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<ImageView
android:id="#+id/ivImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="8dp"
android:src="#drawable/imgadd" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="#+id/tvName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Tom Cruise"
android:textColor="#166CED"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="#+id/tvDateOfBirth"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#D64530"
android:text="Date of Birth: July 3, 1962" />
<TextView
android:id="#+id/tvHeight"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Height: 1.80 m"
android:textColor="#D64530"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="#+id/tvCountry"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#D64530"
android:text="United States" />
</LinearLayout>
</LinearLayout>
<TextView
android:id="#+id/tvDescriptionn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#009A57"
android:text="Description" />
<TextView
android:id="#+id/tvSpouse"
android:layout_width="wrap_content" android:textColor="#166CED"
android:layout_height="wrap_content"
android:text="Spouse: Katie Holmes" />
<TextView
android:id="#+id/tvChildren"
android:layout_width="wrap_content" android:textColor="#166CED"
android:layout_height="wrap_content"
android:text="Children: Suri Cruise, Isabella Jane Cruise, Connor Cruise" />
</LinearLayout>
Fragment_accueil.xml (my fragment 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:id="#+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="4dp"
android:orientation="vertical"
tools:context="info.androidhive.navigationdrawer.fragment.AccueilFragment">
<ListView
android:id="#+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:listitem="#layout/articles">
</ListView>
</LinearLayout>
fragment_accueil.java (my fragment activity)
//import.....
public class AccueilFragment extends Fragment {
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private String mParam1;
private String mParam2;
int score = 0;
TextView t1, t2, t3,t4;
ImageView img;
private OnFragmentInteractionListener mListener;
public AccueilFragment() {
}
public static AccueilFragment newInstance(String param1, String param2) {
AccueilFragment fragment = new AccueilFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_accueil, container, false);
t1 = (TextView) view.findViewById(R.id.tvName);
t2 = (TextView) view.findViewById(R.id.tvDateOfBirth);
t3 = (TextView) view.findViewById(R.id.tvHeight);
t3 = (TextView) view.findViewById(R.id.tvCountry);
img = (ImageView) view.findViewById(R.id.ivImage);
ArrayList actorsList = new ArrayList<Actors>();
ListView listview = (ListView) view.findViewById(R.id.list);
ListAdapter adapter = new ActorAdapter(getActivity().getApplicationContext(), R.layout.articles, actorsList);
listview.setAdapter(adapter);
new getData().execute();
return view;
}
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
class getData extends AsyncTask<String, String, String> {
HttpURLConnection urlConnection;
#Override
protected String doInBackground(String... args) {
StringBuilder result = new StringBuilder();
try {
URL url = new URL("http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors");
urlConnection = (HttpURLConnection) url.openConnection();
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
String line;
while ((line = reader.readLine()) != null) {
result.append(line);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
urlConnection.disconnect();
}
return result.toString();
}
#Override
protected void onPostExecute(String result) {
try {
JSONObject jsono = new JSONObject(result);
JSONArray jarray = jsono.getJSONArray("actors");
for (int i = 0; i < jarray.length(); i++) {
JSONObject object = jarray.getJSONObject(i);
Actors actor = new Actors();
actor.setName(object.getString("name"));
actor.setDescription(object.getString("description"));
actor.setDob(object.getString("dob"));
actor.setCountry(object.getString("country"));
actor.setHeight(object.getString("height"));
actor.setSpouse(object.getString("spouse"));
actor.setChildren(object.getString("children"));
actor.setImage(object.getString("image"));
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
void onFragmentInteraction(Uri uri);
}
}
What's the problem and how to fix that ? thanks

There is couple of things wrong:
1.You are not adding Actors actor = new Actors(); to the actorsList
2.Calling this:
ArrayList actorsList = new ArrayList<Actors>();
ListView listview = (ListView) view.findViewById(R.id.list);
ListAdapter adapter = new ActorAdapter(getActivity().getApplicationContext(), R.layout.articles, actorsList);
will reuslt in blank data in listview
I would suggest you to add the data in your onPostExecute() to the Arraylist and then initialize the adapter with the data.
or you can also call
adapter.notifyDataSetChanged() in onPostExecute()

Are you adding the ListView in your fragment that you want it to be displayed for example:
public class FragmentMain extends Fragment
{
private ListView listView; //Define the list view up here.
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//Set the listview equal to the fragment name
listView = inflater.inflate(R.layout.fragment_name, container, false);
}
}
This should work, let me know if otherwize :)

Unable to populate any Cards in RecyclerView, possible cause?

I am trying to populate CardView's inside a RecyclerView. Though I am able to log all the adapter values(to make sure they are non-empty) I can't populate any in the UI. Here is the Activity Code:
FoodActivity.class
public class FoodActivity extends AppCompatActivity
{
private RecyclerView foodView;
private List<Result> adapter_data;
private CustomPlacesAdapter adapter;
private LinearLayoutManager llm;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_food);
foodView = (RecyclerView)findViewById(R.id.foodRView);
adapter = new CustomPlacesAdapter(adapter_data);
adapter_data = new ArrayList<>();
llm = new LinearLayoutManager(this);
foodView.setLayoutManager(llm);
foodView.setAdapter(adapter);
doGetRequest("restaurants in los angeles airport");
}
private void doGetRequest(final String message)
{
ApiInterfacePlaces apiService =
ApiClientPlaces.getClient().create(ApiInterfacePlaces.class);
Call<PlacesPojo> call = apiService.getValues(message, Util.getKeyForPlaces());
call.enqueue(new Callback<PlacesPojo>()
{
#Override
public void onResponse(Call<PlacesPojo>call, Response<PlacesPojo> response)
{
try
{
Log.e("TAG",""+response.body().toString());
List<Result> response_res = response.body().getResults();
adapter_data = response_res;
adapter.notifyDataSetChanged();
}
catch (Exception e)
{
Toast.makeText(FoodActivity.this, "Check data connection", Toast.LENGTH_SHORT).show();
}
}
#Override
public void onFailure(Call<PlacesPojo> call, Throwable t) {
// Log error here since request failed
Log.e("FAILURE", t.toString());
}
});
}
}
Here is the code to the RecyclerView's adapter:
CustomPlacesAdapter.class
public class CustomPlacesAdapter extends RecyclerView.Adapter<CustomPlacesAdapter.HotelsViewHolder>
{
private DataHolder d2 = new DataHolder();
public class HotelsViewHolder extends RecyclerView.ViewHolder
{
private TextView hotelName;
private Typeface face;
private ImageView hotel_logo;
private Context mcontext;
HotelsViewHolder(View itemView)
{
super(itemView);
mcontext = itemView.getContext();
hotelName = (TextView)itemView.findViewById(R.id.hotelName);
face = Typeface.createFromAsset(itemView.getContext().getAssets(), "Fonts/Roboto-Regular.ttf");
hotelName.setTypeface(face);
hotel_logo = (ImageView)itemView.findViewById(R.id.logoOfHotel);
}
}
private static class DataHolder
{
List<Result> feeds;
}
public CustomPlacesAdapter(List<Result> feeds)
{
this.d2.feeds = feeds;
}
#Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
}
#Override
public HotelsViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.food_item, viewGroup, false);
HotelsViewHolder pvh = new HotelsViewHolder(v);
return pvh;
}
#Override
public void onBindViewHolder(HotelsViewHolder feedViewHolder, int i)
{
feedViewHolder.hotelName.setText(d2.feeds.get(i).getName());
Picasso.with(feedViewHolder.mcontext).load(d2.feeds.get(i).getIcon()).into(feedViewHolder.hotel_logo);
}
#Override
public int getItemCount()
{
if(d2.feeds!=null)
{
return d2.feeds.size();
}
else
{
return 0;
}
}
}
This is the CardView that I use:
food_item.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_centerHorizontal="true"
app:cardCornerRadius="5dp"
android:layout_height="100dp"
card_view:cardUseCompatPadding="false"
android:id="#+id/cv">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:id="#+id/logoOfHotel"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="#+id/hotelName"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</RelativeLayout>
</android.support.v7.widget.CardView>
Cross checked many things, still unable to fix the issue, what is possibly causing this? Any help would be much appreciated.

Android: calling getview() for ListView's Adapter from Fragment in viewPager

I have ViewPager that containing 3 different Fragment. each Fragment containing A Different View and also ListView, I got a problem when I was trying to show the ListView in one of Fragment from ViewPager, it doesn't show anything. I've tried to debug my adapter and it seems my getView() method is not called. I try to call my Fragment not from ViewPager, the result is getView() is called from adapter and ListView is showing. Is there any problem to show ListView from ViewPager? I have tried this solution by calling my adapter from onViewCreated() but there's nothing change. so is there any wrong with my method? this is my code :
My Fragment Class for Managing ViewPager
public class Frag_Provider extends Fragment {
private String[] tabsTitles = {"TERDEKAT", "SEMUA", "PROVIDERKU"};
String url = "";
List<ModelProvider> list_provider;
DB_Esehat db_esehat = null;
SQLiteDatabase db = null;
ContentLoadingProgressBar progressbar;
TabLayout tabLayout;
ViewPager pager;
public Frag_Provider (){
}
#Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container,
Bundle savedInstanceState) {
((MainActivity) getActivity()).custom_toolbar("Provider", R.color.toolbar_provider, R.color.toolbar_provider_dark);
View result=inflater.inflate(R.layout.fragment_provider, container, false);
list_provider = new ArrayList<ModelProvider>();
progressbar = (ContentLoadingProgressBar)result.findViewById(R.id.progressbar);
db_esehat = new DB_Esehat(getActivity());
db = db_esehat.getWritableDatabase();
db.delete("LST_PROVIDER", null, null);
pager=(ViewPager)result.findViewById(R.id.pager);
tabLayout = (TabLayout)result.findViewById(R.id.sliding_tabs);
url = getResources().getString(R.string.url_host)+getResources().getString(R.string.url_provider);
new ProviderTask(url).execute();
pager.setAdapter(buildAdapter(tabsTitles));
tabLayout.post(new Runnable() {
#Override
public void run() {
tabLayout.setupWithViewPager(pager);
}
});
return(result);
}
public class ProviderTask extends AsyncTask<String, Void, String> {
String url = "";
public ProviderTask(String url) {
this.url = url;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
progressbar.setVisibility(View.VISIBLE);
}
#Override
protected String doInBackground(String... params) {
String result = "";
try {
result = Connection.get(url);
} catch (Exception e) {
result = "";
}
return result;
}
#Override
protected void onPostExecute(String result) {
progressbar.setVisibility(View.GONE);
pager.setVisibility(View.VISIBLE);
tabLayout.setVisibility(View.VISIBLE);
super.onPostExecute(result);
if (result.equals("") || result.equals(null)) {
MethodSupport.AlertDialog(getActivity());
} else {
try {
JSONArray Data = new JSONArray(result);
for (int i = 0; i < Data.length(); i++) {
String LSKA_NOTE = "";
String RSALAMAT = "";
String RSTELEPON = "";
String RSNAMA = "";
String MAPPOS = "";
int RSTYPE = 0;
int RSID = 0;
int RS_NTT = 0;
JSONObject json = Data.getJSONObject(i);
if (json.has("LSKA_NOTE")) {
LSKA_NOTE = json.getString("LSKA_NOTE");
}
if (json.has("RSALAMAT")) {
RSALAMAT = json.getString("RSALAMAT");
}
if (json.has("RSTELEPON")) {
RSTELEPON = json.getString("RSTELEPON");
}
if (json.has("RSNAMA")) {
RSNAMA = json.getString("RSNAMA");
}
if (json.has("MAPPOS")) {
MAPPOS = json.getString("MAPPOS");
}
if (json.has("RSTYPE")) {
RSTYPE = json.getInt("RSTYPE");
}
if (json.has("RSID")) {
RSID = json.getInt("RSID");
}
if (json.has("RS_NTT")) {
RS_NTT = json.getInt("RS_NTT");
}
db_esehat.InsertRS(LSKA_NOTE, RSALAMAT, RSTELEPON, RSNAMA, MAPPOS, RSTYPE, RSID, RS_NTT);
}
} catch (Exception e) {
Log.d("TES", e.getMessage());
}
}
}
}
private PagerAdapter buildAdapter(String[] tabsTitles) {
return(new FragmentStatePagerAdapter(getActivity(), getChildFragmentManager(),tabsTitles));
}
}
This is FragmentStatePagerAdapter.java
public class FragmentStatePagerAdapter extends FragmentPagerAdapter {
Context ctxt=null;
private String[] tabsTitles;
public FragmentStatePagerAdapter(Context ctxt, FragmentManager mgr, String[] tabsTitles) {
super(mgr);
this.ctxt=ctxt;
this.tabsTitles = tabsTitles;
}
#Override
public int getCount() {
return tabsTitles.length;
}
#Override
public Fragment getItem(int position) {
switch(position) {
case 0:
return Frag_Provider_Terdekat.newInstance(position);
case 1:
return Frag_Provider_Semua.newInstance(position);
case 2:
return Frag_Provider_Ku.newInstance(position);
}
return null;
}
// #Override public float getPageWidth(int position) { return(0.7f); }
#Override
public String getPageTitle(int position) {
return tabsTitles[position];
}
}
this is my Fragment_Provider.xml, Layout for managing my ViewPager
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v4.widget.ContentLoadingProgressBar
android:id="#+id/progressbar"
style="?android:attr/progressBarStyleLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:visibility="gone"
android:indeterminate="false" />
<android.support.design.widget.TabLayout
android:id="#+id/sliding_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMaxWidth="0dp"
app:tabGravity="fill"
style="#style/MyCustomTabLayout"
app:tabMode="fixed"
android:fillViewport="true"
android:visibility="gone" />
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="fill_parent"
android:layout_height="0px"
android:layout_weight="1"
android:background="#android:color/white"
android:layout_below="#id/sliding_tabs"
android:visibility="gone"/>
</RelativeLayout>
This is of my Fragment in ViewPagerthat containing ListView :
public class Frag_Provider_Terdekat extends Fragment {
private static final String KEY_POSITION="position";
private ListView list_provider;
List<ModelProviderTerdekat> list_ekamedicare;
DB_Esehat db_esehat;
SQLiteDatabase db;
ProviderTerdekatAdapter adapter;
static Frag_Provider_Terdekat newInstance(int position) {
Frag_Provider_Terdekat frag=new Frag_Provider_Terdekat();
Bundle args=new Bundle();
args.putInt(KEY_POSITION, position);
frag.setArguments(args);
return(frag);
}
static String getTitle(Context ctxt, int position) {
return("PROVIDER KU");
}
#Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container,
Bundle savedInstanceState) {
View result=inflater.inflate(R.layout.fragment_child_providerterdekat, container, false);
list_provider = (ListView)result.findViewById(R.id.list_provider);
list_ekamedicare = new ArrayList<ModelProviderTerdekat>();
db_esehat = new DB_Esehat(getActivity());
list_ekamedicare = db_esehat.getProvider();
adapter = new ProviderTerdekatAdapter(getActivity().getApplicationContext(), R.layout.adapter_provider, list_ekamedicare);
list_provider.setAdapter(adapter);
return result;
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
}
#Override
public void onDetach() {
super.onDetach();
}
}
and this is Adapter for my ListView
public class ProviderTerdekatAdapter extends ArrayAdapter<ModelProviderTerdekat> {
List<ModelProviderTerdekat> data = Collections.emptyList();
private LayoutInflater inflater;
private Context context;
static class ViewHolder {
ImageView imvprov_map;
ImageView imvprov_fav;
TextView textprov_nama_rs;
TextView textprov_alamat_rs;
TextView textprov_km_rs;
}
public ProviderTerdekatAdapter (Context context, int viewResourceId, List<ModelProviderTerdekat> data) {
super(context, R.layout.adapter_provider, data);
this.context = context;
inflater = LayoutInflater.from(context);
this.data = data;
}
#Override
public int getCount() {
return data.size();
}
#Override
public long getItemId(int arg0) {
return 0;
}
#Override
public View getView(int position, View view, ViewGroup parent) {
if (view == null) {
view = inflater.inflate(R.layout.adapter_provider, parent, false);
ViewHolder viewHolder = new ViewHolder();
viewHolder.imvprov_map = (ImageView) view.findViewById(R.id.imvprov_map);
viewHolder.imvprov_fav = (ImageView) view.findViewById(R.id.imvprov_fav);
viewHolder.textprov_nama_rs = (TextView) view.findViewById(R.id.textprov_nama_rs);
viewHolder.textprov_alamat_rs = (TextView) view.findViewById(R.id.textprov_alamat_rs);
viewHolder.textprov_km_rs = (TextView) view.findViewById(R.id.textprov_km_rs);
view.setTag(viewHolder);
}
ViewHolder viewHolder = (ViewHolder) view.getTag();
viewHolder.textprov_nama_rs.setText(data.get(position).getRSNAMA());
viewHolder.textprov_alamat_rs.setText(data.get(position).getRSALAMAT());
return view;
}
}
I have no Idea why my GetView() not called in my Adapter, is it because I put in ViewPager? well I hope someone understand about it and help me to solver my problem. thank you very much.

Finally.. I found a solution for my problem, it's because I put ViewPager in RelativeLayout after I change into LinearLayout all view displayed as I wanted
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v4.widget.ContentLoadingProgressBar
android:id="#+id/progressbar"
style="?android:attr/progressBarStyleLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:visibility="gone"
android:indeterminate="false" />
<android.support.design.widget.TabLayout
android:id="#+id/sliding_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMaxWidth="0dp"
app:tabGravity="fill"
style="#style/MyCustomTabLayout"
app:tabMode="fixed"
android:fillViewport="true"
android:visibility="gone" />
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="fill_parent"
android:layout_height="0px"
android:layout_weight="1"
android:background="#android:color/white"
android:layout_below="#id/sliding_tabs"
android:visibility="gone"/>
</LinearLayout>

NullPointerException while listview fills

I have MainActivity class where I parse an HTML page with JSOUP and I also have custom adapter which store data for each row in my ListView. So I get data with JSOUP and it's ok as my LogCat tell me. But when I try to put data to my ListView I get an error.
My activity_main layout:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<ListView
android:id="#+id/listView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" >
</ListView>
</RelativeLayout>
My list_item layout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:minHeight="50dp"
android:orientation="horizontal" >
<ImageView
android:id="#+id/thumbImageNews"
android:layout_marginLeft="10dp"
android:layout_width="120dp"
android:layout_height="120dp"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true" />
<TextView
android:id="#+id/titleNews"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/thumbImageNews"
android:paddingLeft="5dp"
android:paddingRight="0dp"
android:paddingTop="5dp"
android:text=""
android:textColor="#ff0d075c"
android:textStyle="italic"
android:typeface="sans"
android:gravity="center"
android:layout_marginTop="10dp" />
<TextView
android:id="#+id/date2News"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/thumbImageNews"
android:paddingLeft="5dp"
android:paddingRight="0dp"
android:paddingTop="2dp"
android:text=""
android:textColor="#ff585858"
android:textSize="12sp"
android:layout_marginLeft="10dp"/>
</RelativeLayout>
CustomListAdapter activity:
public class CustomListAdapter extends BaseAdapter {
private ArrayList<FeedItem> listData;
private LayoutInflater layoutInflater;
private Context mContext;
public CustomListAdapter(Context context, ArrayList<FeedItem> listData) {
this.listData = listData;
layoutInflater = LayoutInflater.from(context);
mContext = context;
}
#Override
public int getCount() {
return listData.size();
}
#Override
public Object getItem(int position) {
return listData.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = layoutInflater.inflate(R.layout.list_item, null);
holder = new ViewHolder();
holder.headlineView = (TextView) convertView.findViewById(R.id.titleNews);
holder.reportedDateView = (TextView) convertView.findViewById(R.id.date2News);
holder.imageView = (ImageView) convertView.findViewById(R.id.thumbImageNews);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
FeedItem newsItem = (FeedItem) listData.get(position);
holder.headlineView.setText(newsItem.getTitle());
// holder.reportedDateView.setText(newsItem.getDate());
if (holder.imageView != null) {
new ImageDownloaderTask(holder.imageView).execute(newsItem.getAttachmentUrl());
}
return convertView;
}
static class ViewHolder {
TextView headlineView;
TextView reportedDateView;
ImageView imageView;
}
}
FeedItem class to store data for each row:
public class FeedItem implements Serializable {
private String title;
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
private String date;
public String getAttachmentUrl() {
return attachmentUrl;
}
public void setAttachmentUrl(String attachmentUrl) {
this.attachmentUrl = attachmentUrl;
}
private String attachmentUrl;
}
And my MainActivity class where executes all main functions:
public class MainActivity extends Activity {
public Elements title;
public Elements picture;
final String ATTRIBUTE_NAME_TEXT = "text";
final String ATTRIBUTE_NAME_IMAGE = "image";
final String ATTRIBUTE_NAME_DATE = "date";
private ArrayList<FeedItem> feedList = null;
private ListView feedListView = null;
public CustomListAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
feedListView = (ListView) findViewById(R.id.listView1);
new NewThread().execute();
}
public class NewThread extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... arg) {
Document doc;
try {
doc = Jsoup.connect("http://example.com/news/").get();
title = doc.select("h2[class=et_pt_title]");
picture = doc.select("img");
for (Element titles : title) {
FeedItem item = new FeedItem();
item.setTitle(titles.text());
Log.w("title",""+item.getTitle());
feedList.add(item);
}
for (Element img : picture){
String iurl;
iurl = img.absUrl("src");
FeedItem item = new FeedItem();
item.setAttachmentUrl(iurl);
Log.w("imgUrl",""+item.getAttachmentUrl());
feedList.add(item);
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result) {
adapter = new CustomListAdapter(MainActivity.this,feedList);
feedListView.setAdapter(adapter);
}
}
}
So my problem is that when feedList.add(item); executes I get NullPointerException, but Log.w("title",""+item.getTitle()); shows me that everything is ok. What I do wrong?

Your feedList is not initialized.
So before adding items to it, please initialize.
ArrayList<FeedItem> feedList = new ArrayList<FeedItem> ;
Add the above line before you call the AsyncTask i.e. before new NewThread().execute();
It should look like this
feedList = new ArrayList<FeedItem> ;
new NewThread().execute();

Your mistake was you have just declared this
private ArrayList<FeedItem> feedList = null;
not initialized. So just initialize on onCreate() method.
feedList = new ArrayList<FeedItem> ;

private ArrayList<FeedItem> feedList = null;
without create object you are adding data in arraylist
feedList.add(item);
please create object
feedList = new ArrayList<FeedItem>()
than Add
feedList.add(item);