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How can I save a list within a list using the room persistence library? (android & Java)

how are you, I hope everyone is fine
I have created an application to generate a sales invoice.
In SalesInvoiceActivity, when the user clicks on the FloatingActionButton, it goes to AddSaleInvoiceActivity.
addSaleInvoiceFab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
startActivity(new Intent(SalesInvoiceActivity.this, AddSaleInvoiceActivity.class));
}
});
In AddSaleInvoiceActivity there is an EditText and Date to store the name of the customer and invoice date in RecyclerView list in SalesInvoiceActivity.
customerName = addCustomerNameEt.getText().toString();
date = new Date();
When the user presses the Save Invoice button, the invoice number is saved with the ID, the invoice date, and the customer's name.
final SaleInvoiceEntry saleInvoiceEntry = new SaleInvoiceEntry(customerName, date);
appDatabase.salesInvoiceDao().insertSaleInvoice(saleInvoiceEntry);
#Entity(tableName = "saleInvoice")
public class SaleInvoiceEntry {
#PrimaryKey(autoGenerate = true)
private int id;
#ColumnInfo(name = "customerName")
private String customerName;
#ColumnInfo(name = "invoiceDate")
private Date invoiceDate;
#Ignore
public SaleInvoiceEntry(String customerName, Date invoiceDate) {
this.customerName = customerName;
this.invoiceDate = invoiceDate;
}
public SaleInvoiceEntry(int id) {
this.id = id;
}
public void setId(int id) {
this.id = id;
}
public int getId() {
return id;
}
public void setCustomerName(String customerName) {
this.customerName = customerName;
}
public String getCustomerName() {
return customerName;
}
public void setInvoiceDate(Date invoiceDate) {
this.invoiceDate = invoiceDate;
}
public Date getInvoiceDate() {
return invoiceDate;
}
}
#Dao
public interface SalesInvoiceDao {
#Query("SELECT * FROM saleInvoice ORDER BY id")
LiveData<List<SaleInvoiceEntry>> loadAllSalesInvoice();
#Query("SELECT * FROM saleInvoice WHERE id = :saleInvoiceId")
LiveData<SaleInvoiceEntry> loadSalesInvoiceById(int saleInvoiceId);
#Insert
void insertSaleInvoice(SaleInvoiceEntry saleInvoiceEntry);
#Update(onConflict = OnConflictStrategy.REPLACE)
void updateSaleInvoice(SaleInvoiceEntry saleInvoiceEntry);
#Delete
void deleteSaleInvoice(SaleInvoiceEntry saleInvoiceEntry);
}
public class SalesInvoiceAdapter extends RecyclerView.Adapter<SalesInvoiceAdapter.SalesInvoiceViewHolder>
implements AddProductToSaleInvoiceAdapter.ItemClickListener {
private static final String DATE_FORMAT = "dd/MM/yyy";
private final SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT, Locale.getDefault());
private final ItemClickListener itemClickListener;
private List<SaleInvoiceEntry> saleInvoiceEntries;
private final Context context;
private AppDatabase appDatabase;
private String saleInvoiceNumber, customerName, saleInvoiceDate;
public SalesInvoiceAdapter(Context context, ItemClickListener listener, AppDatabase appDatabase) {
this.context = context;
itemClickListener = listener;
this.appDatabase = appDatabase;
}
#NonNull
#Override
public SalesInvoiceViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.sales_list, parent, false);
return new SalesInvoiceViewHolder(view);
}
#SuppressLint({"SetTextI18n", "NotifyDataSetChanged"})
#Override
public void onBindViewHolder(SalesInvoiceViewHolder salesInvoiceViewHolder, int saleInvoicePosition) {
SaleInvoiceEntry saleInvoiceEntry = saleInvoiceEntries.get(saleInvoicePosition);
saleInvoiceNumber = String.valueOf(saleInvoiceEntry.getId());
salesInvoiceViewHolder.saleInvoiceNumberView.setText(context.getString(R.string.sale_invoice_number) + " : " + saleInvoiceNumber);
customerName = saleInvoiceEntry.getCustomerName();
salesInvoiceViewHolder.customerNameView.setText(context.getString(R.string.customer_name) + " : " + customerName);
saleInvoiceDate = dateFormat.format(saleInvoiceEntry.getInvoiceDate());
salesInvoiceViewHolder.saleInvoiceDateView.setText(context.getString(R.string.invoice_date) + " : " + saleInvoiceDate);
appDatabase = AppDatabase.getInstance(context);
salesInvoiceViewHolder.deleteSaleInvoice.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
MaterialAlertDialogBuilder builder = new MaterialAlertDialogBuilder(context, R.style.CutShapeTheme);
builder.setTitle(context.getString(R.string.delete_invoice))
.setMessage(context.getString(R.string.delete_invoice_message))
.setPositiveButton(context.getString(R.string.yes), (dialogInterface, i) -> {
try {
AppExecutors.getInstance().diskIO().execute(new Runnable() {
#Override
public void run() {
int saleInvoicePosition = salesInvoiceViewHolder.getAdapterPosition();
appDatabase.salesInvoiceDao().deleteSaleInvoice(saleInvoiceEntries.get(saleInvoicePosition));
}
});
Toast.makeText(context, context.getString(R.string.invoice_deleted), Toast.LENGTH_SHORT).show();
} catch (Exception e) {
e.printStackTrace();
}
})
.setCancelable(false)
.setNegativeButton(context.getString(R.string.no), (dialog, which) -> {
})
.create().show();
}
});
salesInvoiceViewHolder.editSaleInvoice.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent saleInvoiceIntent = new Intent(context, AddSaleInvoiceActivity.class);
int saleInvoiceId = saleInvoiceEntries.get(salesInvoiceViewHolder.getAdapterPosition()).getId();
saleInvoiceIntent.putExtra(EXTRA_SALE_INVOICE_ID, saleInvoiceId);
context.startActivity(saleInvoiceIntent);
}
});
}
#Override
public int getItemCount() {
if (saleInvoiceEntries == null) {
return 0;
}
return saleInvoiceEntries.size();
}
public List<SaleInvoiceEntry> getSaleInvoiceEntries() {
return saleInvoiceEntries;
}
#SuppressLint("NotifyDataSetChanged")
public void setSaleInvoiceEntries(List<SaleInvoiceEntry> saleInvoiceEntries) {
this.saleInvoiceEntries = saleInvoiceEntries;
notifyDataSetChanged();
}
#Override
public void onItemClickListener(int productId, String productName) {
}
public interface ItemClickListener {
void onItemClickListener(int saleInvoiceId, String customerName);
}
class SalesInvoiceViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private final TextView saleInvoiceNumberView, customerNameView, saleInvoiceDateView;
private final ImageView deleteSaleInvoice, editSaleInvoice;
public SalesInvoiceViewHolder(View itemView) {
super(itemView);
saleInvoiceNumberView = itemView.findViewById(R.id.listInvoiceNumber);
customerNameView = itemView.findViewById(R.id.listCustomerName);
saleInvoiceDateView = itemView.findViewById(R.id.listInvoiceDate);
deleteSaleInvoice = itemView.findViewById(R.id.listDeleteSaleInvoice);
editSaleInvoice = itemView.findViewById(R.id.listEditSaleInvoice);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
int saleInvoiceId = saleInvoiceEntries.get(getAdapterPosition()).getId();
String customerName = saleInvoiceEntries.get(getAdapterPosition()).getCustomerName();
itemClickListener.onItemClickListener(saleInvoiceId, customerName);
}
}
}
public class SalesInvoiceActivity extends AppCompatActivity implements SalesInvoiceAdapter.ItemClickListener {
private FloatingActionButton addSaleInvoiceFab;
private RecyclerView salesInvoiceRv;
private SalesInvoiceAdapter salesInvoiceAdapter;
private AppDatabase appDatabase;
private View salesInvoiceEmptyView;
private SearchView salesInvoiceSv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sales_invoice);
initSalesInvoiceView();
setupSalesInvoiceViewModel();
setupSalesInvoiceRecycleView();
addSaleInvoiceFab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
startActivity(new Intent(SalesInvoiceActivity.this, AddSaleInvoiceActivity.class));
}
});
salesInvoiceSv.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
#Override
public boolean onQueryTextSubmit(String query) {
return false;
}
#Override
public boolean onQueryTextChange(String newText) {
setupSalesInvoiceViewModel();
salesInvoiceFilter(newText);
return true;
}
});
}
private void salesInvoiceFilter(String text) {
ArrayList<SaleInvoiceEntry> salesInvoiceList = new ArrayList<>();
for (SaleInvoiceEntry saleInvoice : salesInvoiceAdapter.getSaleInvoiceEntries()) {
if (saleInvoice.getCustomerName().toLowerCase().contains(text.toLowerCase())) {
salesInvoiceList.add(saleInvoice);
}
}
if (salesInvoiceList.isEmpty()) {
Toast.makeText(this, getString(R.string.no_invoice), Toast.LENGTH_SHORT).show();
} else {
salesInvoiceAdapter.setSaleInvoiceEntries(salesInvoiceList);
}
}
private void initSalesInvoiceView() {
salesInvoiceEmptyView = findViewById(R.id.salesInvoiceEmptyView);
addSaleInvoiceFab = findViewById(R.id.addSaleInvoiceFab);
salesInvoiceRv = findViewById(R.id.salesInvoiceRv);
salesInvoiceSv = findViewById(R.id.saleSearchView);
}
private void setupSalesInvoiceRecycleView() {
appDatabase = AppDatabase.getInstance(getApplicationContext());
salesInvoiceAdapter = new SalesInvoiceAdapter(this, this, appDatabase);
salesInvoiceRv.setHasFixedSize(true);
salesInvoiceRv.setLayoutManager(new LinearLayoutManager(this));
salesInvoiceRv.setAdapter(salesInvoiceAdapter);
}
private void setupSalesInvoiceViewModel() {
MainViewModel mainViewModel = ViewModelProviders.of(this).get(MainViewModel.class);
mainViewModel.getListSalesInvoiceLiveData().observe(this, new Observer<List<SaleInvoiceEntry>>() {
#SuppressLint("NotifyDataSetChanged")
#Override
public void onChanged(#Nullable List<SaleInvoiceEntry> saleInvoiceEntries) {
salesInvoiceAdapter.setSaleInvoiceEntries(saleInvoiceEntries);
salesInvoiceAdapter.notifyDataSetChanged();
if (salesInvoiceAdapter.getItemCount() == 0) {
salesInvoiceRv.setVisibility(View.GONE);
salesInvoiceEmptyView.setVisibility(View.VISIBLE);
salesInvoiceSv.setVisibility(View.GONE);
} else {
salesInvoiceRv.setVisibility(View.VISIBLE);
salesInvoiceEmptyView.setVisibility(View.GONE);
salesInvoiceSv.setVisibility(View.VISIBLE);
}
}
});
}
#Override
public void onItemClickListener(int saleInvoiceId, String customerName) {
Intent intent = new Intent(SalesInvoiceActivity.this, SaleDetailsActivity.class);
intent.putExtra("saleInvoiceId", saleInvoiceId);
intent.putExtra("productName", customerName);
startActivity(intent);
}
}
In AddSaleInvoiceActivity, I created a button that when the user clicks on it, it will be directed to the product store to capture the name of the product, selling price and store it in the RecyclerView list inside AddSaleInvoiceActivity
private Button addProductToSaleInvoiceBtn;
private void initAddProductToSaleInvoiceViews() {
addProductToSaleInvoiceBtn = findViewById(R.id.addProductToSaleInvoiceBtn);
addProductToSaleInvoiceBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent productToSaleInvoiceIntent = new Intent(AddSaleInvoiceActivity.this, ProductStoreActivity.class);
productToSaleInvoiceIntent.putExtra(EXTRA_PRODUCT_TO_SALE_INVOICE_ID, 1);
startActivity(productToSaleInvoiceIntent);
}
});
productToSaleInvoiceRv = findViewById(R.id.productToSaleInvoiceRv);
addProductToSaleInvoiceAdapter = new AddProductToSaleInvoiceAdapter(this, this, appDatabase);
productToSaleInvoiceRv.setHasFixedSize(true);
productToSaleInvoiceRv.setLayoutManager(new LinearLayoutManager(this));
productToSaleInvoiceRv.setAdapter(addProductToSaleInvoiceAdapter);
MainViewModel mainViewModel = ViewModelProviders.of(this).get(MainViewModel.class);
mainViewModel.getListToSalesInvoiceLiveData().observe(this, new Observer<List<AddProductToSalesInvoiceEntry>>() {
#SuppressLint("NotifyDataSetChanged")
#Override
public void onChanged(#Nullable List<AddProductToSalesInvoiceEntry> addProductToSalesInvoiceEntries) {
addProductToSaleInvoiceAdapter.setProductToSalesInvoiceEntries(addProductToSalesInvoiceEntries);
addProductToSaleInvoiceAdapter.notifyDataSetChanged();
}
});
}
#Entity(tableName = "addProductToSalesInvoice")
public class AddProductToSalesInvoiceEntry {
#PrimaryKey(autoGenerate = true)
private int addProductToSalesInvoiceId;
private final String toSalesInvoiceProductName;
private final int toSalesInvoiceProductQuantity;
private final float toSalesInvoiceProductSellingPrice;
#Ignore
public AddProductToSalesInvoiceEntry(String toSalesInvoiceProductName, int toSalesInvoiceProductQuantity
, float toSalesInvoiceProductSellingPrice) {
this.toSalesInvoiceProductName = toSalesInvoiceProductName;
this.toSalesInvoiceProductQuantity = toSalesInvoiceProductQuantity;
this.toSalesInvoiceProductSellingPrice = toSalesInvoiceProductSellingPrice;
}
public AddProductToSalesInvoiceEntry(int addProductToSalesInvoiceId, String toSalesInvoiceProductName, int toSalesInvoiceProductQuantity
, float toSalesInvoiceProductSellingPrice) {
this.addProductToSalesInvoiceId = addProductToSalesInvoiceId;
this.toSalesInvoiceProductName = toSalesInvoiceProductName;
this.toSalesInvoiceProductQuantity = toSalesInvoiceProductQuantity;
this.toSalesInvoiceProductSellingPrice = toSalesInvoiceProductSellingPrice;
}
public int getAddProductToSalesInvoiceId() {
return addProductToSalesInvoiceId;
}
public void setAddProductToSalesInvoiceId(int addProductToSalesInvoiceId) {
this.addProductToSalesInvoiceId = addProductToSalesInvoiceId;
}
public String getToSalesInvoiceProductName() {
return toSalesInvoiceProductName;
}
public int getToSalesInvoiceProductQuantity() {
return toSalesInvoiceProductQuantity;
}
public float getToSalesInvoiceProductSellingPrice() {
return toSalesInvoiceProductSellingPrice;
}
}
#Dao
public interface AddProductToSalesInvoiceDao {
#Query("SELECT * FROM addProductToSalesInvoice ORDER BY addProductToSalesInvoiceId")
LiveData<List<AddProductToSalesInvoiceEntry>> addProductToSalesInvoiceLoadAllProducts();
#Query("SELECT * FROM addProductToSalesInvoice WHERE addProductToSalesInvoiceId = :addProductToSalesInvoiceProductId")
LiveData<AddProductToSalesInvoiceEntry> addProductToSalesInvoiceLoadProductsById(int addProductToSalesInvoiceProductId);
#Insert
void addProductToSalesInvoiceInsertProduct(AddProductToSalesInvoiceEntry addProductToSalesInvoiceEntry);
#Update(onConflict = OnConflictStrategy.REPLACE)
void addProductToSalesInvoiceUpdateProduct(AddProductToSalesInvoiceEntry addProductToSalesInvoiceEntry);
#Delete
void addProductToSalesInvoiceDeleteProduct(AddProductToSalesInvoiceEntry addProductToSalesInvoiceEntry);
#Delete
void addProductToSalesInvoiceDeleteAllProduct(List<AddProductToSalesInvoiceEntry> toSalesInvoiceEntries);
}
public class AddProductToSaleInvoiceAdapter extends RecyclerView
.Adapter<AddProductToSaleInvoiceAdapter.AddProductToSalesInvoiceViewHolder> {
private final ItemClickListener addProductToSalesInvoiceItemClickListener;
private List<AddProductToSalesInvoiceEntry> addProductToSalesInvoiceEntries;
private final Context context;
private AppDatabase appDatabase;
private String addProductToSalesInvoiceProductName;
private int addProductToSalesInvoiceProductQuantity;
private float addProductToSalesInvoiceProductSellingPrice;
private List<AddProductToSalesInvoiceEntry> addProductToSalesInvoiceEntryList;
public AddProductToSaleInvoiceAdapter(Context context, ItemClickListener listener, AppDatabase appDatabase) {
this.context = context;
addProductToSalesInvoiceItemClickListener = listener;
this.appDatabase = appDatabase;
}
#NonNull
#Override
public AddProductToSalesInvoiceViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.add_products_to_sale_invoice_list, parent, false);
return new AddProductToSalesInvoiceViewHolder(view);
}
#SuppressLint("SetTextI18n")
#Override
public void onBindViewHolder(AddProductToSalesInvoiceViewHolder addProductToSalesInvoiceViewHolder
, int productToSalesInvoicePosition) {
AddProductToSalesInvoiceEntry addProductToSalesInvoiceEntry
= addProductToSalesInvoiceEntries.get(productToSalesInvoicePosition);
addProductToSalesInvoiceProductName = addProductToSalesInvoiceEntry.getToSalesInvoiceProductName();
addProductToSalesInvoiceViewHolder.listAddProductToSalesInvoiceProductNameView.setText(addProductToSalesInvoiceProductName);
addProductToSalesInvoiceProductQuantity = addProductToSalesInvoiceEntry.getToSalesInvoiceProductQuantity();
addProductToSalesInvoiceViewHolder.listAddProductToSalesInvoiceProductQuantityView.setText("" + addProductToSalesInvoiceProductQuantity);
addProductToSalesInvoiceProductSellingPrice = addProductToSalesInvoiceEntry.getToSalesInvoiceProductSellingPrice();
addProductToSalesInvoiceViewHolder.listAddProductToSalesInvoiceProductSellingPriceView.setText("" + addProductToSalesInvoiceProductSellingPrice);
addProductToSalesInvoiceViewHolder.productSellingPriceView.setText(context.getString(R.string.product_selling_price) + " : " + addProductToSalesInvoiceProductSellingPrice);
#Override
public int getItemCount() {
if (addProductToSalesInvoiceEntries == null) {
return 0;
}
return addProductToSalesInvoiceEntries.size();
}
public List<AddProductToSalesInvoiceEntry> getAddProductToSalesInvoiceEntries
(ArrayList<AddProductToSalesInvoiceEntry> uProductToSalesInvoiceList) {
return addProductToSalesInvoiceEntries;
}
#SuppressLint("NotifyDataSetChanged")
public void setProductToSalesInvoiceEntries(List<AddProductToSalesInvoiceEntry> addProductToSalesInvoiceEntries) {
this.addProductToSalesInvoiceEntries = addProductToSalesInvoiceEntries;
notifyDataSetChanged();
}
public interface ItemClickListener {
void onItemClickListener(int productId, String productName);
}
class AddProductToSalesInvoiceViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private final TextView listAddProductToSalesInvoiceProductNameView, listAddProductToSalesInvoiceProductQuantityView
, listAddProductToSalesInvoiceProductSellingPriceView;
public AddProductToSalesInvoiceViewHolder(View itemView) {
super(itemView);
listAddProductToSalesInvoiceProductNameView = itemView
.findViewById(R.id.listAddProductToSalesInvoiceProductNameView);
listAddProductToSalesInvoiceProductQuantityView = itemView
.findViewById(R.id.listAddProductToSalesInvoiceProductQuantityView);
listAddProductToSalesInvoiceProductSellingPriceView = itemView
.findViewById(R.id.listAddProductToSalesInvoiceProductSellingPriceView);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View view) {
int productId = addProductToSalesInvoiceEntries.get(getAdapterPosition()).getAddProductToSalesInvoiceId();
String productName = addProductToSalesInvoiceEntries.get(getAdapterPosition()).getToSalesInvoiceProductName();
addProductToSalesInvoiceItemClickListener.onItemClickListener(productId, productName);
}
}
}
Now how do I store the AddProductToSalesInvoiceEntry list inside the SaleInvoiceEntry list when the user clicks the save invoice button ?

How to show multiple data source data in single recycle view or adapter using LazyLoading?

The above image is a simple design that I want to develop.
I have four type of different data with different view type like the below image enter image description here. but that is not a problem. problem is the data will come from different API with lazy loading like when user scroll the list from recycle view it will grab the data from the server. My question is how to combine them in a single adapter because I need to use lazy loading .so I can't load whole data at a time so I need to call the different type of API like goal-list API, appraisal API, post API etc. When user scroll. anyone can give me an idea with example. How can I handle that? Also when user will scroll it will call another api likeCount and comment count also. Currently, In my, I am calling single API and show that in the single recycle view. Currently, I am using android architecture component LiveData
Fragment :
public class NewsFeedFragment extends FcaFragment {
private View view;
private RecyclerView postRecyclerView;
private PostsAdapter postsAdapter;
private List<Post> posts;
private TimelineViewModel timelineViewModel;
private ImageView addPostView;
private View addPostPanel;
private long lastApiCallTime;
private SwipyRefreshLayout swipeRefresh;
private long lastScroolItemInPost= 0;
public NewsFeedFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if(lastScroolItemInPost < 1) {
initViewModel(1 , 0 , true);
lastScroolItemInPost = 1;
}else {
initViewModel(((int) lastScroolItemInPost + 5), lastScroolItemInPost , true);
lastScroolItemInPost += 5;
}
final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(ownerActivity);
view = inflater.inflate(R.layout.fragment_news_feed, container, false);
postRecyclerView = (RecyclerView) view.findViewById(R.id.postRecyclerView);
postRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
#Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
#Override
public void onScrolled(RecyclerView postRecyclerView, int dx, int dy) {
super.onScrolled(postRecyclerView, dx, dy);
int lastVisiableItemInPostList = linearLayoutManager.findLastVisibleItemPosition();
if(lastScroolItemInPost < lastVisiableItemInPostList)
{
if(lastScroolItemInPost == 1)
{
initViewModel((int) (lastScroolItemInPost + 2), ( lastScroolItemInPost - 2 ) , false);
lastScroolItemInPost += 2;
}else{
initViewModel((int) (lastScroolItemInPost + 2), ( lastScroolItemInPost - 2 ) , false );
lastScroolItemInPost += 2;
}
}
}
});
posts = new ArrayList<>();
postRecyclerView.setLayoutManager(linearLayoutManager);
postsAdapter = new PostsAdapter(ownerActivity,posts,timelineViewModel);
postRecyclerView.setAdapter(postsAdapter);
swipeRefresh = (SwipyRefreshLayout) view.findViewById(R.id.swipeRefresh);
swipeRefresh.setOnRefreshListener(new SwipyRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh(SwipyRefreshLayoutDirection direction) {
if(direction == SwipyRefreshLayoutDirection.TOP){
timelineViewModel.fetchPosts2();
}
if(direction == SwipyRefreshLayoutDirection.BOTTOM){
timelineViewModel.fetchPosts();
}
}
});
return view;
}
private void initViewModel(int lastVisiableItemInPostList , long lastScroolItemInPost , boolean isFirstTimeOpenFeedFragment) {
TimelineViewModel.Factory factory = new TimelineViewModel.Factory(UserPreferences.getToken(ownerActivity), TaskUtils.getMySelfContact(ownerActivity));
timelineViewModel = ViewModelProviders.of(this,factory).get(TimelineViewModel.class);
timelineViewModel.getPostList().observe(this, new Observer<List<Post>>() {
#Override
public void onChanged(#Nullable List<Post> posts) {
postsAdapter.setPostList(posts);
swipeRefresh.setRefreshing(false);
}
});
timelineViewModel.getPostDeleted().observe(this, new Observer<Boolean>() {
#Override
public void onChanged(#Nullable Boolean aBoolean) {
if(aBoolean){
postsAdapter.setPostList(Post.getAll());
}
}
});
timelineViewModel.init( lastVisiableItemInPostList , lastScroolItemInPost ,isFirstTimeOpenFeedFragment);
}
}
ViewModel :
public class TimelineViewModel extends FCViewModel implements PostDetailsDownloadManager.PostDetailDownloadedListener,OnContactReceivedListner{
public TimelineViewModel(String token,Contact user){
super(token);
this.user = user;
post = new MutableLiveData<>();
postDeleted = new MutableLiveData<>();
}
public void init(int lastVisiableItemInPostList , long lastScroolItemInPost , boolean isFirstTimeOpenFeedFragment){
repository =
//postDetailsDownloadManager = ServiceLocator.getServiceLocator().postDetailsDownloadManager;
likePostDownloadManager = ServiceLocator.getServiceLocator().likePostDownloadManager;
likePostDownloadManager.setPostDetailDownloadedListener(new DataDownloadManager.DataDownloadedListener<LikePostTouple>() {
#Override
public void onDataDownloaded(List<LikePostTouple> dataTouple) {
TimelineViewModel.this.post.setValue(Post.getAll());
}
#Override
public void onSingleDataDownloaded(LikePostTouple dataTouple) {
}
});
postDetailDownloadManager = ServiceLocator.getServiceLocator().postDetailDownloadManager;
postDetailDownloadManager.setPostDetailDownloadedListener(new DataDownloadManager.DataDownloadedListener<PostTouple>() {
#Override
public void onDataDownloaded(List<PostTouple> dataTouple) {
TimelineViewModel.this.post.setValue(Post.getAll());
}
#Override
public void onSingleDataDownloaded(PostTouple dataTouple) {
}
});
post.setValue(Post.getAll());
if(isFirstTimeOpenFeedFragment)
{
fetchPosts2();
}
try {
if(Post.getAll().size() > 0)
{
List<Post> tempPosts = Post.getAll();
List<Post> passList = tempPosts.subList( (int) lastScroolItemInPost ,lastVisiableItemInPostList);
fetchLikesOfPosts(passList);
}else{
fetchLikesOfPosts(Post.getAll());
}
} catch (Exception e) {
e.printStackTrace();
}
Log.d("Testing Injecting", repository.toString());
}
public LiveData<List<Post>> getPostList() {
return post;
}
public MutableLiveData<Boolean> getPostDeleted() {
return postDeleted;
}
boolean isContactFetched = false;
public void fetchPosts(){
if(Contact.getAll().size() < 1){
fetchContacts();
return;
}
Map<String,Object> requestData = new HashMap<>();
requestData.put("type",1);
requestData.put("cpid",Post.getLastPid());
isDataLoading = true;
repository.getData(new Repository.DataFetchedListener<List<Post>>() {
#Override
public void onDataFetched(List<Post> posts) {
isDataLoading = false;
Log.d("fetched posts",""+posts.size());
post.setValue(Post.getAll());
fetchPostDetails(posts);
if(posts.size() > 0){
fetchLikesOfPosts(posts);
}
}
},requestData);
}
private boolean isDataLoading = false;
public void fetchPosts2(){
if(Contact.getAll().size() < 1){
fetchContacts();
return;
}
Map<String,Object> requestData = new HashMap<>();
requestData.put("type",2);
requestData.put("cpid", Post.getFirstPid()); // cpid means cursor pid
isDataLoading = true;
repository.getData(new Repository.DataFetchedListener<List<Post>>() {
#Override
public void onDataFetched(List<Post> posts) {
isDataLoading = false;
Log.d("fetched posts",""+posts.size());
post.setValue(Post.getAll());
fetchPostDetails(posts);
if(posts.size() > 0){
fetchLikesOfPosts(posts);
}
}
},requestData);
}
public boolean isDataLoading() {
return isDataLoading;
}
private void fetchContacts() {
contactRepository.getData(new Repository.DataFetchedListener<List<Contact>>() {
#Override
public void onDataFetched(List<Contact> data) {
if(data.size()>0 && !isContactFetched) {
fetchPosts2();
isContactFetched = true;
}
}
},null);
}
#NonNull
private PostTouple getPostToubleFromPost(Post post) throws JSONException {
Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create();
String json = gson.toJson(post);
JSONObject postJson = new JSONObject(json);
return new PostTouple(postJson,post.getPid());
}
#NonNull
private LikePostTouple getLkePostToupleFromPost(Post post) throws JSONException {
Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create();
String json = gson.toJson(post);
JSONObject postJson = new JSONObject(json);
return new LikePostTouple(postJson,post.getPid());
}
public void giveLike(String token, final long pid){
Map<String,Object> requestData = new HashMap<>();
requestData.put("token",token);
requestData.put("pid",Long.toString(pid));
likeRepository.postData(new Repository.DataFetchedListener<Post>() {
#Override
public void onDataFetched(Post data) {
Log.d("Like post", data.toString());
Post post = getPostById(pid);
post.setLikes(data.getLikes());
post.setComments(data.getComments());
TimelineViewModel.this.post.setValue(TimelineViewModel.this.post.getValue());
fetchLikesOfLikedPost(data);
}
},requestData);
}
private void fetchLikesOfLikedPost(Post data) {
try {
likePostDownloadManager.addItemInQueue(getLkePostToupleFromPost(data));
likePostDownloadManager.startDownload();
} catch (JSONException e) {
e.printStackTrace();
}
}
private Post getPostById(long pid){
List<Post> posts = post.getValue();
for(Post post : posts){
if(post.getPid()==pid){
return post;
}
}
return null;
}
public Contact getSenderContactFromComment(Post post) {
if(post.getPqrc().equals(user.getUserId())){
return user;
}
Contact contact = Contact.getByUserId(post.getPqrc());
return contact;
}
public String getDescriptionForType5(Post post,String message){
try {
PostDetail postDetail = PostDetail.getByPostId(post.getPid());
if(postDetail!=null) {
String qrc = JSonUtils.qrcFromCntOfPostDetails(postDetail.getContent());
int sid = JSonUtils.skillidFromCntOfPostDetails(postDetail.getContent());
if (qrc == null || sid == 0) {
return "";
}
SkillDb skill = SkillDb.getBySId(Integer.toString(sid));
Contact contact = getPosterContact(post.getPqrc());
return contact.getName() + " " + message + " " + skill.getSkillName() + ".";
}
return "";
} catch (Exception e) {
e.printStackTrace();
}
return "";
}
public String getDescriptionForPost(Post post, String message){
if(post.getCtype()==1){
return post.getDescr();
}
if(post.getCtype() == 2){
String postDetail = getContent(post);
if (postDetail != null) return Html.fromHtml(""+postDetail+"").toString();
}
if(post.getCtype()==5){
return getDescriptionForType5(post, message);
}
return "";
}
#Nullable
public String getContent(Post post) {
PostDetail postDetail = PostDetail.getByPostId(post.getPid());
if(postDetail!=null){
return postDetail.getContent();
}
return null;
}
public Contact getPosterContact(String qrc){
try {
String userqrc = user.getUserId();
if (userqrc.equals(qrc)) {
return user;
}
}catch (Exception e){
e.printStackTrace();
}
try {
return Contact.getByUserId(qrc);
}catch (Exception e){
e.printStackTrace();
}
return null;
}
public void fetchUrlPreview(String url, final UrlMetaDataFetchListener metaDataFetchListener){
String modifiedUrl = !url.contains("http://")&&!url.contains("https://")? "http://"+url : url;
TextCrawler textCrawler = new TextCrawler();
LinkPreviewCallback linkPreviewCallback = new LinkPreviewCallback() {
#Override
public void onPre() {
}
#Override
public void onPos(SourceContent sourceContent, boolean b) {
String imageUrl = sourceContent.getImages().isEmpty()? "" : sourceContent.getImages().get(0);
metaDataFetchListener.onMetaDataFetched(sourceContent.getTitle(),sourceContent.getDescription(), imageUrl);
}
};
textCrawler.makePreview(linkPreviewCallback, modifiedUrl,1);
}
public interface UrlMetaDataFetchListener{
void onMetaDataFetched(String title, String description, String imageUrl);
}
#Override
public void onPostDownloaded(PostTouple postTouple) {
this.post.setValue(Post.getAll());
}
#Override
public void onContactsReceived() {
fetchPosts();
}
public void deletePost(long pid) {
Map<String, Object> requestData = new HashMap<>();
requestData.put("token",token);
requestData.put("pid",pid);
repository.postData(new Repository.DataFetchedListener<Post>() {
#Override
public void onDataFetched(Post data) {
postDeleted.setValue(data!=null);
}
},requestData);
}
public boolean isMyPost(Post post){
return user.getUserId().equals(post.getPqrc());
}
public static class Factory extends ViewModelProvider.NewInstanceFactory {
private String token;
private Contact user;
public Factory(String token,Contact user) {
this.token = token;
this.user = user;
}
#Override
public <T extends ViewModel> T create(Class<T> modelClass) {
return (T) new TimelineViewModel(token,user);
}
}
}
Adapter :
public class PostsAdapter extends RecyclerView.Adapter {
private Context context;
private List<Post> postList;
private int[] badges = {R.drawable.badge1, R.drawable.badge2, R.drawable.badge3};
private List<Integer> randomNumbers = Utils.getRandomNumberList(2,true);
private ArrayDeque<Integer> randomQueue = new ArrayDeque<>(randomNumbers);
private static Map<Long,URLPreview> urlPreviewMap = new HashMap<>();
private TimelineViewModel timelineViewModel;
public PostsAdapter(Context context, List<Post> postList, TimelineViewModel timelineViewModel){
super();
this.context = context;
this.postList = postList;
this.timelineViewModel = timelineViewModel;
}
#Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.post_item_layout, null);
PostViewHolder postViewHolder = new PostViewHolder(view);
postViewHolder.setIsRecyclable(false);
return postViewHolder;
}
#Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
final Post post = postList.get(position);
final PostViewHolder postViewHolder = (PostViewHolder) holder;
final String postDetail = timelineViewModel.getDescriptionForPost(post,context.getResources().getString(R.string.postType5message));
setPostDescription(post, postViewHolder, postDetail);
handlePreviewVisibility(post, postViewHolder);
postViewHolder.setLikes(""+post.getLikes()+" Likes");
postViewHolder.setCommentCount("" + post.getComments() + " Comments");
postViewHolder.setSupDescription("Posted By System");
int randomNumber = getRandomNumber();
postViewHolder.setBadgeIcon(badges[randomNumber]);
setPostLikedIndicator(post, postViewHolder);
postViewHolder.getLikeButtonWrapper().setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
giveLikeToPost(post);
if(post.getIsLiked() == 0) {
post.setLikes(post.getLikes() + 1);
postViewHolder.setLikes("" + post.getLikes() + " Likes");
post.setIsLiked(1);
setPostLikedIndicator(post, postViewHolder);
}
}
});
postViewHolder.getCommentPanel().setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
CommentPostFragment fragment = CommentPostFragment.GetInstance(post.getPid());
ViewUtils.launchFragmentKeepingInBackStack(context,fragment);
}
});
Contact contact = timelineViewModel.getPosterContact(post.getPqrc());
if(contact!=null && TaskUtils.isNotEmpty(contact.getImageToken())){
Utils.setImageToImageView(postViewHolder.getPosterImage(),timelineViewModel.getToken(),contact.getImageToken());
postViewHolder.getPosterNameTextView().setText(contact.getName());
}
postViewHolder.getPostingDate().setText(Utils.getDateFromMilliseconds(post.getdC()));
if(post.getCtype() != 3)
{
postViewHolder.contentImage.setVisibility(View.GONE);
postViewHolder.fullScreenIndicatorIcon.setVisibility(View.GONE);
}
if(post.getCtype() == 3){
setContentOfType3(post, postViewHolder);
}
}
#Override
public void onViewRecycled(RecyclerView.ViewHolder holder) {
super.onViewRecycled(holder);
PostViewHolder viewHolder = (PostViewHolder) holder;
viewHolder.pTitle.setText("");
viewHolder.pDescription.setText("");
viewHolder.pImage.setImageDrawable(null);
}
private void handlePreviewVisibility(Post post, PostViewHolder postViewHolder) {
if(post.getCtype()==2){
postViewHolder.preview.setVisibility(View.VISIBLE);
}else{
postViewHolder.preview.setVisibility(View.GONE);
}
}
private void handleShowingOptionsIcon(Post post, PostViewHolder postViewHolder) {
if(post.getCtype()!=5 && timelineViewModel.isMyPost(post)){
postViewHolder.options.setVisibility(View.VISIBLE);
}else{
postViewHolder.options.setVisibility(View.GONE);
}
}
private void giveLikeToPost(Post post) {
post.setLikes(post.getLikes()+1);
post.setIsLiked(1);
//notifyDataSetChanged();
timelineViewModel.giveLike(UserPreferences.getToken(context),post.getPid());
}
private void setPostLikedIndicator(Post post, PostViewHolder postViewHolder) {
if(post.getIsLiked()==1) {
postViewHolder.getLikeButton().setImageDrawable(ResourcesCompat.getDrawable(context.getResources(), R.drawable.ic_like_red, null));
}else{
postViewHolder.getLikeButton().setImageDrawable(ResourcesCompat.getDrawable(context.getResources(), R.drawable.ic_like_filled, null));
}
}
private void setPostDescription(final Post post, final PostViewHolder postViewHolder, final String postDetail) {
if(post.getCtype()==2){
String postDescription = "<p>"+ post.getDescr()+"</p>";
postViewHolder.description.setText( Html.fromHtml(postDescription +""+postDetail+"") );
postViewHolder.descriptionContainer.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String url = !postDetail.contains("http://")&&!postDetail.contains("https://")? "http://"+postDetail : postDetail;
Uri uri = Uri.parse(url);
context.startActivity(new Intent(Intent.ACTION_VIEW,uri));
}
});
URLPreview urlPreview = null;
if((urlPreview=urlPreviewMap.get(post.getPid()))==null) {
timelineViewModel.fetchUrlPreview(postDetail, new TimelineViewModel.UrlMetaDataFetchListener() {
#Override
public void onMetaDataFetched(String title, String description, String imageUrl) {
showURLPreview(title, description, imageUrl, postViewHolder);
urlPreviewMap.put(post.getPid(),new URLPreview(title,description,imageUrl));
}
});
}else {
showURLPreview(urlPreview.getTitle(),urlPreview.getDescription(),urlPreview.getImageUrl(),postViewHolder);
}
}else if(post.getCtype() == 3)
{
String postDescription = post.getDescr();
postViewHolder.description.setText(postDescription);
}
else {
postViewHolder.setDescription(postDetail);
}
}
private void initImageClickListener(final ImageView imageView, final String pictureLink) {
imageView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
List<String> pictureLinks = new ArrayList<String>();
pictureLinks.add(pictureLink);
int[] screenLocation = new int[2];
imageView.getLocationOnScreen(screenLocation);
ImagePagerFragment imagePagerFragment = ImagePagerFragment.newInstance(pictureLinks, 0, screenLocation, imageView.getWidth(), imageView.getHeight());
ViewUtils.launchPopUpFragmentUpdated(context, imagePagerFragment);
}
});
}
private void showURLPreview(String title, String description, String imageUrl, PostViewHolder postViewHolder) {
context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if(!TaskUtils.isEmpty(imageUrl)) {
Picasso.with(context)
.load(imageUrl)
.into(postViewHolder.pImage);
}
view.findViewById(R.id.description);
postViewHolder.pTitle.setText(title);
postViewHolder.pDescription.setText(description);
}
#Override
public int getItemCount() {
return postList.size();
}
private int getRandomNumber(){
if(!randomQueue.isEmpty()){
return randomQueue.poll();
}
randomQueue = new ArrayDeque<>(randomNumbers);
return randomQueue.poll();
}
public void setPostList(List<Post> postList) {
this.postList = postList;
notifyDataSetChanged();
Log.d("Data rec", postList.size()+"");
}
class PostViewHolder extends RecyclerView.ViewHolder implements PopupMenu.OnMenuItemClickListener {
}
public void setLikes(String likes) {
this.likes.setText(likes);
}
public void setCommentCount(String commentCount)
{
this.commentCount.setText(commentCount);
}
public void setDescription(String description){
this.description.setText(description);
}
public void setSupDescription(String subDescription){
this.supDescription.setText(subDescription);
}
public void setBadgeIcon(int resID){
Utils.setImageViewFromResource(badgeIcon,resID);
}
public ImageView getLikeButton() {
return likeButton;
}
public RelativeLayout getLikeButtonWrapper()
{
return likeButtonWrapper;
}
public ImageView getCommentButton() {
return commentButton;
}
public ImageView getPosterImage() {
return posterImage;
}
public TextView getPosterNameTextView() {
return posterNameTextView;
}
public TextView getPostingDate() {
return postingDate;
}
public RelativeLayout getCommentPanel() {
return commentPanel;
}
#Override
public boolean onMenuItemClick(MenuItem item) {
timelineViewModel.deletePost(postList.get(getAdapterPosition()).getPid());
return false;
}
}
}

java.lang.NullPointerException: Attempt to invoke interface method 'java.util.Iterator java.util.List.iterator()' on a null object reference Retrofit

I'm trying to use blog id to get JSON object from server. At the moment I'm getting this error
java.lang.NullPointerException: Attempt to invoke interface method 'java.util.Iterator java.util.List.iterator()
on a null object reference`.How do I use the post Id to get the full content what am I doing wrong. Please help!!!
MyBlog Adapter:
public class MyBlogAdapter extends RecyclerView.Adapter<BlogViewHolder> {
List<BlogResponse> postsList;
Context context;
public static String blog_Id, blogID;
private LayoutInflater inflater;
public MyBlogAdapter(Context context, List<BlogResponse> postsList){
this.context = context;
this.inflater = LayoutInflater.from(context);
this.postsList = postsList;
}
#Override
public BlogViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.custom_view,parent, false);
return new BlogViewHolder(view);
}
#Override
public void onBindViewHolder(BlogViewHolder holder, int position) {
final BlogResponse posts= postsList.get(position);
holder.summary.setText(posts.getBlogExcerpt().trim().toString());
holder.title.setText(posts.getBlogTitle().trim().toString());
// Glide.with(context).load(posts.getBlogThumbnail()).into(holder.cover);
holder.blogHolder.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(context, AnotherSingleView.class);
blog_Id = posts.getBlogId();
intent.putExtra(blogID,blog_Id);
Log.d("MyblogAdapter","Please check blog Id: "+blog_Id);
context.startActivity(intent);
}
});
}
#Override
public int getItemCount() {
Log.d("MyBlogAdapter,","getItemCount"+postsList.size());
return postsList == null ? (0) : postsList.size();
}
}
SecondActivity:
public class AnotherSingleView extends AppCompatActivity {
String postID;
int position;
public TextView blogTitle,blogSub,blogContent;
public ImageView blogPic;
List<SingleBlogPost> singleBlogPosts;
SingleBlogPost singleBlogPost;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_another_single_view);
Intent intent = getIntent();
Bundle showBlogId = intent.getExtras();
postID = showBlogId.getString(blogID);
Log.d("AnotherSingleView","Please check blog Id: "+postID);
singleBlogPosts = new ArrayList<>();
blogContent = (TextView)findViewById(R.id.blog_content);
blogSub = (TextView) findViewById(R.id.blog_subtitle);
blogTitle =(TextView) findViewById(R.id.blog_title);
blogPic =(ImageView) findViewById(R.id.blog_pix);
singlePostDisplay();
}
private void singlePostDisplay() {
BlogaPI api = ApiClient.getBlogInterface();
Call<List<SingleBlogPost>> call = api.postResponse(postID);
call.enqueue(new Callback<List<SingleBlogPost>>() {
#Override
public void onResponse(Call<List<SingleBlogPost>> call, Response<List<SingleBlogPost>> response) {
singleBlogPosts = response.body();
if (singleBlogPosts != null && !singleBlogPosts.isEmpty() ){
for (SingleBlogPost posts : singleBlogPosts){
Log.d("AnotherSingleView","Please check RESPONSE: "+response.body().toString());
blogTitle.setText(posts.getBlogTitle());
blogSub.setText(posts.getBlogSubtitle());
blogContent.setText(posts.getBlogContent());
// Glide.with(AnotherSingleView.this).load(singlepost.getBlogMedimg()).into(blogPic);
}
}
else{
Toast.makeText(AnotherSingleView.this, "Something is empty", Toast.LENGTH_SHORT).show();
} }
#Override
public void onFailure(Call<List<SingleBlogPost>> call, Throwable t) {
Toast.makeText(AnotherSingleView.this, "check again: "+t.toString(), Toast.LENGTH_SHORT).show();
}
});
}
}
Interface:
public interface BlogaPI {
#GET("blog")
Call<BlogList> response();
#GET("post/{blog_id}")
Call<List<SingleBlogPost>> postResponse(#Path("blog_id") String blog_id);
//Call<List<SingleBlogPost>> postResponse();
}
SingleBlogPost:
public class SingleBlogPost {
#SerializedName("blog_id")
#Expose
private String blogId;
#SerializedName("blog_title")
#Expose
private String blogTitle;
#SerializedName("blog_subtitle")
#Expose
private String blogSubtitle;
#SerializedName("blog_excerpt")
#Expose
private String blogExcerpt;
#SerializedName("blog_content")
#Expose
private String blogContent;
#SerializedName("blog_thumbnail")
#Expose
private String blogThumbnail;
#SerializedName("blog_medimg")
#Expose
private String blogMedimg;
#SerializedName("category_title")
#Expose
private String categoryTitle;
public SingleBlogPost(String blogId,String blogTitle, String blogSubtitle, String blogExcerpt,
String blogContent, String blogThumbnail, String blogMedimg, String categoryTitle){
this.blogId = blogId;
this.blogTitle = blogTitle;
this.blogSubtitle = blogSubtitle;
this.blogExcerpt = blogExcerpt;
this.blogContent = blogContent;
this.blogThumbnail = blogThumbnail;
this.blogMedimg = blogMedimg;
this.categoryTitle = categoryTitle;
}
public String getBlogId() {
return blogId;
}
public void setBlogId(String blogId) {
this.blogId = blogId;
}
public String getBlogTitle() {
return blogTitle;
}
public void setBlogTitle(String blogTitle) {
this.blogTitle = blogTitle;
}
public String getBlogSubtitle() {
return blogSubtitle;
}
public void setBlogSubtitle(String blogSubtitle) {
this.blogSubtitle = blogSubtitle;
}
public String getBlogExcerpt() {
return blogExcerpt;
}
public void setBlogExcerpt(String blogExcerpt) {
this.blogExcerpt = blogExcerpt;
}
public String getBlogContent() {
return blogContent;
}
public void setBlogContent(String blogContent) {
this.blogContent = blogContent;
}
public String getBlogThumbnail() {
return blogThumbnail;
}
public void setBlogThumbnail(String blogThumbnail) {
this.blogThumbnail = blogThumbnail;
}
public String getBlogMedimg() {
return blogMedimg;
}
public void setBlogMedimg(String blogMedimg) {
this.blogMedimg = blogMedimg;
}
public String getCategoryTitle() {
return categoryTitle;
}
public void setCategoryTitle(String categoryTitle) {
this.categoryTitle = categoryTitle;
}
}

Check if the server response is different then null before you do a enhanced for like this:
if(singleBlogPosts!= null) {
for (SingleBlogPosts posts : singleBlogPosts){
Log.d("AnotherSingleView","Please check RESPONSE: "+response.body().toString());
blogTitle.setText(posts.getBlogTitle());
blogSub.setText(posts.getBlogSubtitle());
blogContent.setText(posts.getBlogContent());
// Glide.with(AnotherSingleView.this).load(singlepost.getBlogMedimg()).into(blogPic);
}
}

you question was list iterator,but we can`t see you list use on anywhere,i guess you may be use recyclerView on you data has not get,because get data was asynchronous.try to use data if you can sure it is existing.

NullPointerException while evaluating toString() for anonymous class

Trying to convert JSON array to list of objects using Gson library.
Code:
TypeToken<List<Comment>> token = new TypeToken<List<Comment>>() {}; //this line throws the following exception
public class Comment implements Serializable{
#SerializedName("id")
private int mID;
#SerializedName("content")
private String mContent;
#SerializedName("author")
private String mAuthor;
#SerializedName("author_id")
private int mAuthorID;
#SerializedName("author_email")
private String mAuthorEmail;
#SerializedName("date")
private String mDate;
#SerializedName("name")
private String mName;
#SerializedName("image")
private String mImage;
public int getmID() {
return mID;
}
public void setmID(int mID) {
this.mID = mID;
}
public String getmContent() {
return mContent;
}
public void setmContent(String mContent) {
this.mContent = mContent;
}
public String getmAuthor() {
return mAuthor;
}
public void setmAuthor(String mAuthor) {
this.mAuthor = mAuthor;
}
public int getmAuthorID() {
return mAuthorID;
}
public void setmAuthorID(int mAuthorID) {
this.mAuthorID = mAuthorID;
}
public String getmAuthorEmail() {
return mAuthorEmail;
}
public void setmAuthorEmail(String mAuthorEmail) {
this.mAuthorEmail = mAuthorEmail;
}
public String getmDate() {
return mDate;
}
public void setmDate(String mDate) {
this.mDate = mDate;
}
public String getmName() {
return mName;
}
public void setmName(String mName) {
this.mName = mName;
}
public String getmImage() {
return mImage;
}
public void setmImage(String mImage) {
this.mImage = mImage;
}
}
public class CommentListingActivity extends BaseActivity implements View.OnClickListener {
private static final String TAG = "CommentListingActivity";
private ListView mListViewComments;
private CommentAdapter mCommentAdapter;
private ArrayList<Comment> mCommentList = new ArrayList<Comment>();
private ProgressBar mProgressBar;
private TextView mTextViewErrorMessage;
private Button mButtonRefresh;
private LinearLayout mLinearLayoutError;
private int mPostID;
private boolean isCommentListLoading = true;
private EditText mEditTextComment;
private ImageView mImageViewSend;
private InputMethodManager mInputMethodManager;
private SwipeRefreshLayout mSwipeRefreshLayout;
private boolean mIsRefreshing = false;
private int mOffset = 0;
private View mProgressBarView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_comment_listing);
mPostID = getIntent().getIntExtra("postID",0);
setToolbar();
setToolBarTitle(getString(R.string.commentsLabel));
setToolbarHomeAsUpEnabled(true);
mSwipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipeRefreshLayout);
mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
mSwipeRefreshLayout.setRefreshing(false);
mIsRefreshing = true;
mOffset = 0;
fetchComments();
}
});
mListViewComments = (ListView) findViewById(R.id.listViewComments);
mCommentAdapter = new CommentAdapter(this, mCommentList,mImageLoader);
mListViewComments.setAdapter(mCommentAdapter);
mProgressBarView = getLayoutInflater().inflate(R.layout.recyclerview_loading_item,null);
mListViewComments.addFooterView(mProgressBarView);
// set the custom dialog components - text, image and button
mEditTextComment = (EditText) findViewById(R.id.editTextComment);
mImageViewSend = (ImageView) findViewById(R.id.imageViewSend);
mImageViewSend.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
postComment();
}
});
mEditTextComment.requestFocus();
mInputMethodManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
mInputMethodManager.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);
initProgressBar();
initErrorView();
mListViewComments.setOnScrollListener(new EndlessScrollListener() {
#Override
public boolean onLoadMore(int page, int totalItemsCount) {
mOffset = mOffset + LIST_LIMIT;
mListViewComments.addFooterView(mProgressBarView);
fetchComments();
return true;
}
});
fetchComments();
}
private void fetchComments(){
if (!mIsRefreshing && mCommentAdapter.getCount()==0)
showProgressBar();
HashMap<String,String> parameters = new HashMap<String, String>();
parameters.put("post",String.valueOf(mPostID));
parameters.put("offset",String.valueOf(mOffset));
NetworkUtility.getJSONRquest(this, APIURLs.LIST_COMMENTS, parameters, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
//Remove loading item
if(mCommentList.size()>0) {
mListViewComments.removeFooterView(mProgressBarView);
}
try {
if(response.getString(API_KEY_STATUS).equalsIgnoreCase(API_RESPONSE_SUCCESS)){
JSONArray jsonArrayComments = response.getJSONArray(API_KEY_DATA);
if(jsonArrayComments.length()>0) {
if (mIsRefreshing) {
mCommentList.clear();
mCommentAdapter.notifyDataSetChanged();
}
TypeToken<List<Comment>> token = new TypeToken<List<Comment>>() {};
mCommentList.addAll((Collection<? extends Comment>) GsonUtility.convertJSONStringToObject(jsonArrayComments.toString(), token));
mCommentAdapter.notifyDataSetChanged();
}
mIsRefreshing = false;
if(mCommentAdapter.getCount()>0) {
showContent();
} else {
if (mOffset == 0)
showError("No comments found.");
}
} else {
mProgressBarView.setVisibility(View.GONE);
if(mCommentAdapter.getCount()>0){
AlertDialogUtility.showErrorMessage(CommentListingActivity.this,getString(R.string.errorLabel),response.getString(API_KEY_MESSAGE),getString(R.string.okLabel),null,null,null);
} else
showError(response.getString(API_KEY_MESSAGE));
}
} catch (JSONException e) {
e.printStackTrace();
mProgressBarView.setVisibility(View.GONE);
if(mCommentAdapter.getCount()>0){
AlertDialogUtility.showErrorMessage(CommentListingActivity.this,getString(R.string.errorLabel),getString(R.string.volleyErrorMessage),getString(R.string.okLabel),null,null,null);
} else {
showError(getString(R.string.volleyErrorMessage));
}
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
mProgressBarView.setVisibility(View.GONE);
if(mCommentAdapter.getCount()>0){
AlertDialogUtility.showErrorMessage(CommentListingActivity.this,getString(R.string.errorLabel),getString(R.string.volleyErrorMessage),getString(R.string.okLabel),null,null,null);
} else {
showError(error.getCause().getMessage());
}
error.printStackTrace();
}
},null,TAG);
}
private void postComment() {
final AppProgressDialog appProgressDialog = new AppProgressDialog(this);
appProgressDialog.setProgressDialogTitle("Posting Comment");
appProgressDialog.setProgressDialogMessage("Please Wait...");
appProgressDialog.showProgressDialog();
try {
final String comment = mEditTextComment.getText().toString();
if (!ValidatorUtility.isBlank(comment) && mPostID!=0) {
JSONObject jsonData = new JSONObject();
jsonData.put("content",comment);
jsonData.put("post",mPostID);
NetworkUtility.postRquestWithBasicAuth(this, APIURLs.POST_COMMENT, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
if(response.has("id") && response.getInt("id")>0){
AppToast.toastLong(mContext,"Comment Added");
Comment objComment = new Comment();
if (response.has("author_name"))
objComment.setmAuthor(response.getString("author_name"));
if (response.has("author_email"))
objComment.setmAuthorEmail(response.getString("author_email"));
if (response.has("author"))
objComment.setmAuthorID(response.getInt("author"));
objComment.setmContent(comment);
if (response.has("date"))
objComment.setmDate(response.getString("date"));
if (response.has("id"))
objComment.setmID(response.getInt("id"));
objComment.setmImage(mUser.getImage());
objComment.setmName(mUser.getName());
mCommentList.add(0,objComment);
mCommentAdapter.notifyDataSetChanged();
mEditTextComment.setText(null);
mEditTextComment.clearFocus();
mInputMethodManager.hideSoftInputFromWindow(mEditTextComment.getWindowToken(),0);
showContent();
} else {
AlertDialogUtility.showErrorMessage(CommentListingActivity.this,getString(R.string.errorLabel),"Failed to add comment. Please try again later.",getString(R.string.okLabel),null,null,null);
}
} catch (JSONException e) {
e.printStackTrace();
} finally {
appProgressDialog.dismissProgressDialog();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
appProgressDialog.dismissProgressDialog();
AlertDialogUtility.showErrorMessage(CommentListingActivity.this,getString(R.string.errorLabel),error.getCause().getMessage(),getString(R.string.okLabel),null,null,null);
}
}, jsonData, TAG);
} else {
appProgressDialog.dismissProgressDialog();
}
} catch (Exception e){
e.printStackTrace();
appProgressDialog.dismissProgressDialog();
}
}
private void initProgressBar(){
mProgressBar = (ProgressBar) findViewById(R.id.progressBar);
}
private void initErrorView(){
mLinearLayoutError = (LinearLayout) findViewById(R.id.linearLayoutError);
mTextViewErrorMessage = (TextView) findViewById(R.id.textViewErrorMessage);
mButtonRefresh = (Button) findViewById(R.id.buttonRefresh);
mButtonRefresh.setOnClickListener(this);
}
private void showProgressBar(){
mProgressBar.setVisibility(View.VISIBLE);
mLinearLayoutError.setVisibility(View.GONE);
mSwipeRefreshLayout.setVisibility(View.GONE);
}
private void showContent(){
mProgressBar.setVisibility(View.GONE);
mLinearLayoutError.setVisibility(View.GONE);
mSwipeRefreshLayout.setVisibility(View.VISIBLE);
}
private void showError(String message){
mProgressBar.setVisibility(View.GONE);
mLinearLayoutError.setVisibility(View.VISIBLE);
mSwipeRefreshLayout.setVisibility(View.GONE);
mTextViewErrorMessage.setText(message);
}
#Override
public void onClick(View view) {
if(view == mButtonRefresh){
fetchComments();
}
}
#Override
protected void onDestroy() {
super.onDestroy();
KeyboardUtility.closeKeyboard(this,mEditTextComment);
}
}
Exception:
Method threw 'java.lang.NullPointerException' exception. Cannot evaluate app.govindaconnect.mangaltaraproductions.com.views.CommentListingActivity$4$1.toString()
Only 1 JSON objects get converted and added to the list.
What might be causing the exception? Because this is not happening with other classes.

You can try this
replace this line
TypeToken<List<Comment>> token = new TypeToken<List<Comment>>() {};
with this and try
Type token = new TypeToken<List<Comment>>() {}.getType();
List<Comment> commentsList = gson.fromJson(String.valueOf(resultArray), type);

I took JSON array in a string variable and then it started working.

why don't you try Jackson parser for conversion, it's much simpler and easier
example for you :
List<Comment> list=null;
String json="your json array";
ObjectMapper mapper = new ObjectMapper();
try {
list= mapper.readValue(json, new TypeReference<List<Comment>>(){});
} catch (IOException e) {
throw new Exception(e);
}

How to handle java.lang.NumberFormatException: Invalid double: "" error in Android Studio?

I'm trying to run an application and it crashes because of this error:
FATAL EXCEPTION: main
Process: com.panaceasoft.citiesdirectory, PID: 4201
com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: Invalid double: ""
It had some Gradle errors, but I had solved them, and now it still crashed when I tried to run the app. It looks like that problem is in the class below, at line 252. Tried everything possible to check data and to solve this error, but nothing so far. What should I do? Thanks!
CitiesListFragment:
public class CitiesListFragment extends Fragment {
//-------------------------------------------------------------------------------------------------------------------------------------
//region // Private Variables
//-------------------------------------------------------------------------------------------------------------------------------------
private RecyclerView mRecyclerView;
private ProgressWheel progressWheel;
private CityAdapter adapter;
private SwipeRefreshLayout swipeRefreshLayout;
private TextView display_message;
private ArrayList<PCityData> pCityDataList;
private ArrayList<PCityData> pCityDataSet;
private NestedScrollView singleLayout;
private TextView scCityName;
private TextView scCityLocation;
private TextView scCityAbout;
private TextView scCityCatCount;
private TextView scCitySubCatCount;
private TextView scCityItemCount;
private ImageView scCityPhoto;
private Button scCityExplore;
private String jsonStatusSuccessString;
private String connectionError;
//-------------------------------------------------------------------------------------------------------------------------------------
//endregion Public Variables
//-------------------------------------------------------------------------------------------------------------------------------------
//-------------------------------------------------------------------------------------------------------------------------------------
//region // Constructor
//-------------------------------------------------------------------------------------------------------------------------------------
public CitiesListFragment() {
}
//-------------------------------------------------------------------------------------------------------------------------------------
//endregion Constructor
//-------------------------------------------------------------------------------------------------------------------------------------
//-------------------------------------------------------------------------------------------------------------------------------------
//region // Override Functions
//-------------------------------------------------------------------------------------------------------------------------------------
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_cities_list, container, false);
initUI(view);
initData();
return view;
}
//-------------------------------------------------------------------------------------------------------------------------------------
//endregion Override Functions
//-------------------------------------------------------------------------------------------------------------------------------------
//-------------------------------------------------------------------------------------------------------------------------------------
//region // Init UI Function
//-------------------------------------------------------------------------------------------------------------------------------------
private void initUI(View view){
initSingleUI(view);
initSwipeRefreshLayout(view);
initProgressWheel(view);
initRecyclerView(view);
startLoading();
}
private void initSingleUI(View view) {
singleLayout =(NestedScrollView) view.findViewById(R.id.single_city_layout);
scCityName = (TextView) view.findViewById(R.id.sc_city_name);
scCityLocation = (TextView) view.findViewById(R.id.sc_city_loc);
scCityAbout = (TextView) view.findViewById(R.id.sc_city_desc);
scCityCatCount = (TextView) view.findViewById(R.id.txt_cat_count);
scCitySubCatCount = (TextView) view.findViewById(R.id.txt_sub_cat_count);
scCityItemCount = (TextView) view.findViewById(R.id.txt_item_count);
scCityPhoto = (ImageView) view.findViewById(R.id.sc_city_photo);
scCityExplore = (Button) view.findViewById(R.id.button_explore);
int screenWidth = Utils.getScreenWidth();
int rlWidth = (screenWidth/3) - 20;
RelativeLayout r1 = (RelativeLayout) view.findViewById(R.id.rl_count1);
RelativeLayout r2 = (RelativeLayout) view.findViewById(R.id.rl_count2);
RelativeLayout r3 = (RelativeLayout) view.findViewById(R.id.rl_count3);
r1.setMinimumWidth(rlWidth);
r2.setMinimumWidth(rlWidth);
r3.setMinimumWidth(rlWidth);
scCityPhoto.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if(pCityDataList !=null && pCityDataList.size() > 0) {
final Intent intent;
intent = new Intent(getActivity(), SelectedCityActivity.class);
GlobalData.citydata = pCityDataList.get(0);
intent.putExtra("selected_city_id", pCityDataList.get(0).id);
getActivity().startActivity(intent);
getActivity().overridePendingTransition(R.anim.right_to_left, R.anim.blank_anim);
}
}
});
scCityExplore.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if(pCityDataList !=null && pCityDataList.size() > 0) {
final Intent intent;
intent = new Intent(getActivity(), SelectedCityActivity.class);
GlobalData.citydata = pCityDataList.get(0);
intent.putExtra("selected_city_id", pCityDataList.get(0).id);
getActivity().startActivity(intent);
getActivity().overridePendingTransition(R.anim.right_to_left, R.anim.blank_anim);
}
}
});
}
private void initSwipeRefreshLayout(View view) {
swipeRefreshLayout = (SwipeRefreshLayout) view.findViewById(R.id.swipe_refresh);
swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
requestData(Config.APP_API_URL + Config.GET_ALL);
}
});
}
private void initProgressWheel(View view) {
progressWheel = (ProgressWheel) view.findViewById(R.id.progress_wheel);
}
private void initRecyclerView(View view) {
mRecyclerView = (RecyclerView) view.findViewById(R.id.my_recycler_view);
mRecyclerView.setHasFixedSize(true);
LinearLayoutManager llm = new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(llm);
display_message = (TextView) view.findViewById(R.id.display_message);
display_message.setVisibility(view.GONE);
pCityDataSet = new ArrayList<>();
adapter = new CityAdapter(getActivity(), pCityDataSet);
mRecyclerView.setAdapter(adapter);
mRecyclerView.addOnItemTouchListener(new RecyclerTouchListener(getActivity(), mRecyclerView, new ClickListener() {
#Override
public void onClick(View view, int position) {
onItemClicked(position);
}
#Override
public void onLongClick(View view, int position) {
}
}));
}
//-------------------------------------------------------------------------------------------------------------------------------------
//endregion Init UI Function
//-------------------------------------------------------------------------------------------------------------------------------------
//-------------------------------------------------------------------------------------------------------------------------------------
//region // Init Data Function
//-------------------------------------------------------------------------------------------------------------------------------------
private void initData(){
requestData(Config.APP_API_URL + Config.GET_ALL);
jsonStatusSuccessString = getResources().getString(R.string.json_status_success);
connectionError = getResources().getString(R.string.connection_error);
}
private void requestData(String uri) {
JsonObjectRequest request = new JsonObjectRequest(uri,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
String status = response.getString("status");
if (status.equals(jsonStatusSuccessString)) {
progressWheel.setVisibility(View.GONE);
Gson gson = new Gson();
Type listType = new TypeToken<List<PCityData>>() {
}.getType();
//String data="";
pCityDataList = gson.fromJson(response.getString("Data"), listType);
Utils.psLog("City Count : " + pCityDataList.size());
if(pCityDataList.size() > 1) {
singleLayout.setVisibility(View.GONE);
mRecyclerView.setVisibility(View.VISIBLE);
updateDisplay();
}else{
mRecyclerView.setVisibility(View.GONE);
singleLayout.setVisibility(View.VISIBLE);
stopLoading();
updateSingleDisplay();
}
updateGlobalCityList();
} else {
stopLoading();
Utils.psLog("Error in loading CityList.");
}
} catch (JSONException e) {
Utils.psErrorLogE("Error in loading CityList.", e);
stopLoading();
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError ex) {
progressWheel.setVisibility(View.GONE);
stopLoading();
/* NetworkResponse response = ex.networkResponse;
if (response != null && response.data != null) {
} else {*/
try {
display_message.setVisibility(View.VISIBLE);
display_message.setText(connectionError);
}catch (Exception e){
Utils.psErrorLogE("Error in Connection Url.", e);
}
//}
}
});
request.setRetryPolicy(new DefaultRetryPolicy(
5000,
DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
RequestQueue queue = Volley.newRequestQueue(getActivity().getApplicationContext());
queue.add(request);
}
//-------------------------------------------------------------------------------------------------------------------------------------
//endregion Init Data Function
//-------------------------------------------------------------------------------------------------------------------------------------
//-------------------------------------------------------------------------------------------------------------------------------------
//region // Bind Functions
//-------------------------------------------------------------------------------------------------------------------------------------
private void updateSingleDisplay() {
try {
if (pCityDataList.size() > 0) {
display_message.setVisibility(View.GONE);
singleLayout.startAnimation(AnimationUtils.loadAnimation(getActivity(), R.anim.fade_in));
scCityName.setText(pCityDataList.get(0).name);
scCityLocation.setText(pCityDataList.get(0).address);
scCityAbout.setText(pCityDataList.get(0).description);
scCityCatCount.setText(pCityDataList.get(0).category_count + " Categories");
scCitySubCatCount.setText(pCityDataList.get(0).sub_category_count + " Sub Categories");
scCityItemCount.setText(pCityDataList.get(0).item_count + " Items");
Picasso.with(getActivity()).load(Config.APP_IMAGES_URL + pCityDataList.get(0).cover_image_file).into(scCityPhoto);
}
}catch(Exception e){
Utils.psErrorLogE("Error in single display data binding.", e);
}
}
private void updateGlobalCityList() {
GlobalData.cityDatas.clear();
for (PCityData cd : pCityDataList) {
GlobalData.cityDatas.add(cd);
}
}
private void updateDisplay() {
if (swipeRefreshLayout.isRefreshing()) {
pCityDataSet.clear();
adapter.notifyDataSetChanged();
for (PCityData cd : pCityDataList) {
pCityDataSet.add(cd);
}
} else {
for (PCityData cd : pCityDataList) {
pCityDataSet.add(cd);
}
}
stopLoading();
adapter.notifyItemInserted(pCityDataSet.size());
}
//-------------------------------------------------------------------------------------------------------------------------------------
//endregion Bind Functions
//-------------------------------------------------------------------------------------------------------------------------------------
//-------------------------------------------------------------------------------------------------------------------------------------
//region // Private Functions
//-------------------------------------------------------------------------------------------------------------------------------------
private void onItemClicked(int position) {
Utils.psLog("Position : " + position);
Intent intent;
intent = new Intent(getActivity(),SelectedCityActivity.class);
GlobalData.citydata = pCityDataList.get(position);
intent.putExtra("selected_city_id", pCityDataList.get(position).id);
getActivity().startActivity(intent);
getActivity().overridePendingTransition(R.anim.right_to_left, R.anim.blank_anim);
}
private void startLoading(){
try{
swipeRefreshLayout.post(new Runnable() {
#Override
public void run() {
swipeRefreshLayout.setRefreshing(true);
}
});
}catch (Exception e){}
}
private void stopLoading(){
try {
if (swipeRefreshLayout.isRefreshing()) {
swipeRefreshLayout.setRefreshing(false);
}
}catch (Exception e){}
}
//-------------------------------------------------------------------------------------------------------------------------------------
//endregion Private Functions
//-------------------------------------------------------------------------------------------------------------------------------------
Line 252:
pCityDataList = gson.fromJson(response.getString("data"), listType);
PCityData.class:
package com.panaceasoft.citiesdirectory.models;
import android.os.Parcel;
import android.os.Parcelable;
import java.util.ArrayList;
/**
* Created by Panacea-Soft on 6/8/15.
* Contact Email : teamps.is.cool#gmail.com
*/
public class PCityData implements Parcelable {
public int id;
public String name;
public String description;
public String address;
public String lat;
public String lng;
public String added;
public int status;
public int item_count;
public int category_count;
public int sub_category_count;
public int follow_count;
public String cover_image_file;
public int cover_image_width;
public int cover_image_height;
public String cover_image_description;
public ArrayList<PCategoryData> categories;
protected PCityData(Parcel in) {
id = in.readInt();
name = in.readString();
description = in.readString();
address = in.readString();
lat = in.readString();
lng = in.readString();
added = in.readString();
status = in.readInt();
item_count = in.readInt();
category_count = in.readInt();
sub_category_count = in.readInt();
follow_count = in.readInt();
cover_image_file = in.readString();
cover_image_width = in.readInt();
cover_image_height = in.readInt();
cover_image_description = in.readString();
if (in.readByte() == 0x01) {
categories = new ArrayList<PCategoryData>();
in.readList(categories, PCategoryData.class.getClassLoader());
} else {
categories = null;
}
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(id);
dest.writeString(name);
dest.writeString(description);
dest.writeString(address);
dest.writeString(lat);
dest.writeString(lng);
dest.writeString(added);
dest.writeInt(status);
dest.writeInt(item_count);
dest.writeInt(category_count);
dest.writeInt(sub_category_count);
dest.writeInt(follow_count);
dest.writeString(cover_image_file);
dest.writeInt(cover_image_width);
dest.writeInt(cover_image_height);
dest.writeString(cover_image_description);
if (categories == null) {
dest.writeByte((byte) (0x00));
} else {
dest.writeByte((byte) (0x01));
dest.writeList(categories);
}
}
#SuppressWarnings("unused")
public static final Parcelable.Creator<PCityData> CREATOR = new Parcelable.Creator<PCityData>() {
#Override
public PCityData createFromParcel(Parcel in) {
return new PCityData(in);
}
#Override
public PCityData[] newArray(int size) {
return new PCityData[size];
}
};
}
L.E:
data:
[{"id":"1","name":"Maramureș","description":"Maramureș is a mountainous .","address":"Maramureș, Romania","lat":"0","lng":"0","admin_id":"3","is_approved":"1","paypal_trans_id":"0","added":"2016-07-1420:45:50","status":"1","item_count":85,"category_count":49,"sub_category_count":0,"follow_count":0,"cover_image_file":"singapore.png","cover_image_width":"600","cover_image_height":"400","cover_image_description":"Singapore","categories":
L.E:
PCategoryData.java:
package com.panaceasoft.citiesdirectory.models;
import android.os.Parcel;
import android.os.Parcelable;
import java.util.ArrayList;
/**
* Created by Panacea-Soft on 8/8/15.
* Contact Email : teamps.is.cool#gmail.com
*/
public class PCategoryData implements Parcelable {
public int id;
public int shop_id;
public String name;
public int is_published;
public int ordering;
public String added;
public String updated;
public String cover_image_file;
public int cover_image_width;
public int cover_image_height;
public ArrayList<PSubCategoryData> sub_categories;
public Double value;
protected PCategoryData(Parcel in) {
id = in.readInt();
shop_id = in.readInt();
name = in.readString();
is_published = in.readInt();
ordering = in.readInt();
added = in.readString();
updated = in.readString();
cover_image_file = in.readString();
cover_image_width = in.readInt();
cover_image_height = in.readInt();
if (in.readByte() == 0x01) {
sub_categories = new ArrayList<PSubCategoryData>();
in.readList(sub_categories, PSubCategoryData.class.getClassLoader());
} else {
sub_categories = null;
}
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(id);
dest.writeInt(shop_id);
dest.writeString(name);
dest.writeInt(is_published);
dest.writeInt(ordering);
dest.writeString(added);
dest.writeString(updated);
dest.writeString(cover_image_file);
dest.writeInt(cover_image_width);
dest.writeInt(cover_image_height);
if (sub_categories == null) {
dest.writeByte((byte) (0x00));
} else {
dest.writeByte((byte) (0x01));
dest.writeList(sub_categories);
}
}
#SuppressWarnings("unused")
public static final Parcelable.Creator<PCategoryData> CREATOR = new Parcelable.Creator<PCategoryData>() {
#Override
public PCategoryData createFromParcel(Parcel in) {
return new PCategoryData(in);
}
#Override
public PCategoryData[] newArray(int size) {
return new PCategoryData[size];
}
};
}

I guess that PCategoryData has double field, and guess that json value of that double field is "";
UPDATE
Your code will be like this:
public class CitiesListFragment extends Fragment {
...
private void requestData(String uri) {
...
final GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(PCategoryData.class, new PCategoryDataTypeAdapter());
final Gson gson = gsonBuilder.create();
Type listType = new TypeToken<List<PCityData>>() {
}.getType();
//String data="";
pCityDataList = gson.fromJson(response.getString("Data"), listType);
...
}
...
class PCategoryDataTypeAdapter extends TypeAdapter<PCategoryData> {
#Override
public PCategoryData read(JsonReader in) throws IOException {
final PCategoryData data = new PCategoryData();
in.beginObject();
while (in.hasNext()) {
switch (in.nextName()) {
case "value": //Please change "value" to your field name.
try {
data.value = Double.valueOf(in.nextString());
} catch (NumberFormatException e) {
data.value = 0;
}
break;
}
}
in.endObject();
return data;
}
#Override
public void write(JsonWriter out, PCategoryData data) throws IOException {
out.beginObject();
out.name("value").value(data.value); //Please change "value" to your field name.
out.endObject();
}
}
...
}