Develop Reference

No Data in Recycler View in Fragment

I am building an Android Application which have Tab Layout in which there are Fragments and in Fragment I am displaying some value.
I have just only added hardcoded values to test the layout, but even these are not visible in the fragment.
Here is the code for ViewPagerAdapter:
public class FavouriteViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> favouriteFragmentList = new ArrayList<>(); // this line can cause crashes
private final List<String> favouriteFragmentListTitles = new ArrayList<>();
public FavouriteViewPagerAdapter(#NonNull FragmentManager fm, int behavior) {
super(fm, behavior);
}
#NonNull
#Override
public Fragment getItem(int position) {
return favouriteFragmentList.get(position);
}
#Override
public int getCount() {
return favouriteFragmentListTitles.size();
}
#Nullable
#Override
public CharSequence getPageTitle(int position) {
return favouriteFragmentListTitles.get(position);
}
public void AddFragment(Fragment fragment, String title) {
favouriteFragmentList.add(fragment); // this line can cause crashes
favouriteFragmentListTitles.add(title);
}
}
I have tried the answers available already none of them solves my problem.
I debugged the application and my RecyclerViewAdapter is not even called, very strange. I have done this many time but this never happened.
Here is my code for RecyclerViewAdapter :
public class ProductsRecyclerAdapter extends RecyclerView.Adapter<ProductsRecyclerAdapter.viewHolder> {
Context context;
private List<FavouriteProducts> favouriteProductsData;
public ProductsRecyclerAdapter(Context context, List<FavouriteProducts> favouriteProductsData) {
this.context = context;
this.favouriteProductsData = favouriteProductsData;
}
#NonNull
#Override
public viewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(context).inflate(R.layout.single_favourite_product_item, parent, false);
viewHolder vHolder = new viewHolder(v);
return vHolder;
}
#Override
public void onBindViewHolder(#NonNull viewHolder holder, int position) {
holder.product_name.setText(favouriteProductsData.get(position).getProduct_name());
holder.product_price.setText(favouriteProductsData.get(position).getProduct_price());
holder.product_image.setImageResource(favouriteProductsData.get(position).getProduct_image());
Toast.makeText(context,favouriteProductsData.get(position).getProduct_price() , Toast.LENGTH_SHORT).show();
/*holder.heart_button.setOnLikeListener(new OnLikeListener() {
#Override
public void liked(LikeButton likeButton) {
showSuccessToast(context,"Liked");
}
#Override
public void unLiked(LikeButton likeButton) {
showSuccessToast(context,"Unliked");
}
});*/
}
#Override
public int getItemCount() {
return favouriteProductsData.size();
}
static class viewHolder extends RecyclerView.ViewHolder {
MaterialTextView product_name, product_price;
ImageView product_image;
LikeButton heart_button;
public viewHolder(#NonNull View itemView) {
super(itemView);
product_name = itemView.findViewById(R.id.product_name);
product_price = itemView.findViewById(R.id.product_price);
product_image = itemView.findViewById(R.id.product_image);
heart_button = itemView.findViewById(R.id.heart_button);
}
}
}
I am not getting any errors but after I check adapter is not even called. Some help will be really helpful.
Fragment Code:
public class FavouriteProductsFragment extends Fragment {
View v;
private List<FavouriteProducts> productList;
public FavouriteProductsFragment() {
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
productList = new ArrayList<>();
productList.add(new FavouriteProducts("All Weather", "200/Ltr", R.drawable.all_weather));
}
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
v = inflater.inflate(R.layout.products_favourite_fragment, container, false);
RecyclerView productRecyclerView = v.findViewById(R.id.favourite_products_rv);
ProductsRecyclerAdapter recyclerAdapter = new ProductsRecyclerAdapter(getContext(), productList);
productRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
productRecyclerView.hasFixedSize();
productRecyclerView.setAdapter(recyclerAdapter);
return v;
}
}

productList = new ArrayList<>();
productList.add(new FavouriteProducts("All Weather", "200/Ltr",R.drawable.all_weather));
recyclerAdapter.notifyDataSetChanged()
RecyclerView productRecyclerView = v.findViewById(R.id.favourite_products_rv);
ProductsRecyclerAdapter recyclerAdapter = new ProductsRecyclerAdapter(getContext(), productList);
productRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
productRecyclerView.hasFixedSize();
productRecyclerView.setAdapter(recyclerAdapter);

You need to add
RecyclerView productRecyclerView = v.findViewById(R.id.favourite_products_rv);
ProductsRecyclerAdapter recyclerAdapter = new ProductsRecyclerAdapter(getContext(), productList);
productRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
productRecyclerView.hasFixedSize();
productRecyclerView.setAdapter(recyclerAdapter);
productList = new ArrayList<>();
productList.add(new FavouriteProducts("All Weather", "200/Ltr",R.drawable.all_weather));recyclerAdapter.notifyDataSetChanged()
and Remove oncreate() method

try productRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity())); befor setting adapter in recyclerview.

Step1: First Create one or MoreFragment For Your ViewPager and in This Fragment Add your Recyclerview Code as per Your Requirement.
Like Below Code
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
ViewGroup root = (ViewGroup) inflater.inflate(R.layout.fragment_whatsapp_image, container, false);
context = getActivity();
((HomeActivity) getActivity()).toolbar.setVisibility(View.VISIBLE);
setupView(root);
return root;
}
private void setupView(ViewGroup root) {
recyclerView = (RecyclerView) root.findViewById(R.id.recyclerViewImage);
progressBar=root.findViewById(R.id.simpleProgressBar);
txtinfo=root.findViewById(R.id.txtinfo);
setUPList();
}
Step2: Then Create ViewPager Adapter for Your TabLayout
public class ViewPagerAdapter extends FragmentPagerAdapter {
public ViewPagerAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
}
#Override
public Fragment getItem(int position) {
if(position == 0) return new AudioFragment();
if(position == 1) return new VideoFragment();
if(position == 2) return new ImageFragment();
throw new IllegalStateException("Unexpected position " + position);
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
if(position == 0) return "Audio";
if(position == 1) return "Video";
if(position == 2) return "Image";
throw new IllegalStateException("Unexpected position " + position);
}
}
Step3 : Then Call Your SetupViewpager Method in Your Oncreate method of your Activity
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar=findViewById(R.id.toolbar);
viewPager=findViewById(R.id.viewpager);
tabLayout=findViewById(R.id.tabs);
//add toolbar
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
setupViewPager(viewPager);
tabLayout.setupWithViewPager(viewPager);
setTabIcons();
}
NOTE: You Can Download ViewPager Code from Below Link.Click Here to View and Download

Viewpager wrong OnItemClick position

My app has a fragment that host a nested viewPager (One fragment added every time) all views are linked to the same layout.
Each fragment has a fixed button + recylerview that retrieve its data from firebase adapter.
When I click on the button, it show the correct viewPager position. But if I click on the listview item (viewHolder) it show the next pre-loaded position in the viewPager.
here's the viewpager and the pager adapter of the root fragment
Explore.java
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_explore, container, false);
array = controller.SELECTED_CATEGORIES;
viewPager = (ViewPager) root.findViewById(R.id.viewPager);
tabLayout = (TabLayout) root.findViewById(R.id.categories_tablayout);
tabLayout.setupWithViewPager(viewPager);
mAdapter = new MyAdapter(getFragmentManager());
viewPager.setAdapter(mAdapter);
return root;
}
public static class MyAdapter extends FragmentStatePagerAdapter {
public MyAdapter(FragmentManager fm) {
super(fm);
}
#Override
public int getCount() {
return controller.SELECTED_CATEGORIES.length;
}
#Override
public Fragment getItem(int position) {
return CategoriesFragment.newInstance(position);
}
#Override
public CharSequence getPageTitle(final int position) {
return controller.SELECTED_CATEGORIES[position];
}
}
CategoriesFragment.java
static CategoriesFragment newInstance(int num) {
CategoriesFragment f = new CategoriesFragment();
Bundle args = new Bundle();
args.putInt("num", num);
f.setArguments(args);
return f;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_categories, container, false);
initialize();
listCategoriesFeed = (RecyclerView) rootView.findViewById(R.id.listCategoriesFeeds);
categoriesFeedAdapter = new CategoriesFeedAdapter(CategoriesFeedItem.class, R.layout.categoriesfeed_list_item, CategoriesFeedHolder.class, myref);
llm = new LinearLayoutManager(rootView.getContext());
llm.setOrientation(LinearLayoutManager.VERTICAL);
listCategoriesFeed.setLayoutManager(llm);
listCategoriesFeed.setAdapter(categoriesFeedAdapter);
swipeRefreshLayout = (SwipeRefreshLayout) rootView.findViewById(R.id.swipe_refresh_layout);
swipeRefreshLayout.setOnRefreshListener(this);
//Holder itemClickListener
CategoriesFeedHolder.registerOnItemClickListener(this);
//TextView onclick listener
View tv = rootView.findViewById(R.id.text);
((TextView)tv).setText("Fragment #" + mNum);
tv.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.e("position",mNum + "");
}
});
return rootView;
}
#Override
public void onItemClick(View view, int position) {
super.onItemClick(view, position);
switch (view.getId()) {
case R.id.firstId:
Log.e("position",mNum+ "");
break;
case R.id.secondId:
secondAction....
.....
.....
.....
break;
}
}
private void initialize() {
controller.showProgressDialog();
list = controller.getIniCategoriesDetailsList();
list.clear();
controller.categoriesDetailsList.put(controller.SELECTED_CATEGORIES[mNum],list);
reference = FirebaseDatabase.getInstance().getReference("firebase-path/" + controller.SELECTED_CATEGORIES[mNum]);
myref = reference.orderByChild("order-by").limitToFirst(i);
myref.addChildEventListener(this);
}
CategoriesFeedHolder.java
private CategoriesFeedItem model;
private final ImageView mImage;
private static OnItemClickListener onItemClickListener;
public CategoriesFeedHolder(View itemView) {
super(itemView);
this.context = itemView.getContext();
mImage = (ImageView) itemView.findViewById(R.id.m_image);
mImage.setOnClickListener(this);
}
public static void registerOnItemClickListener(OnItemClickListener onItemClickListener) {
CategoriesFeedHolder.onItemClickListener = onItemClickListener;
}
public void setModel(CategoriesFeedItem model) {
this.model = model;
}
#Override
public void onClick(View view) {
onItemClickListener.onItemClick(view, getAdapterPosition());
}
Does anyone know why this happens?

The problem was with the viewholder class, there was no data binding inside it. So when i clicked on any item inside the viewholder, it performed the action on the current adapter's data (preloaded data).
the viewholder class should be something like this:
public ViewHolder(View itemView) {
super(itemView);
share = (ImageView) itemView.findViewById(R.id.share);
}
public void bindToPost(Post post, View.OnClickListener onClickListener) {
share.setOnClickListener(onClickListener);
}

Communicating between 2 fragments in a Viewpager - Updating RecyclerView in Fragment B from Fragment A

I'm building a simple stock display app that allows you to fetch stocks of interest (frag A), store them in a TinyDB, and display them in a recyclerView (frag B).
The framework used to work fine - until I decided to incorporate a viewpager and Tablayout host. I cannot get the RecyclerView in Frag B to display new data live. This is because the activity viewpager initializes both fragments at launch, meaning you can't call the onCreateView code again, I believe.
Communicating between two fragments through an Activity has been touched before on this site, but I found the best example to be this one:
(https://github.com/kylejablonski/InterfaceDemo),
which uses two interfaces, one to communicate from Frag A to Activity, and another one to communicate from Activity to Frag B. But I have a serious problem -
Currently, clicking both the "clear portfolio" and "add stock" to portfolio buttons in Frag A result in an empty screen in Frag B, which means something is being called yet new data is not being displayed/associated with the Adapter
Activity (https://github.com/EXJUSTICE/Investr/blob/master/app/src/main/java/com/xu/investo/ViewHolderActivity.java)
public class ViewHolderActivity extends AppCompatActivity implements CommunicateToActivity,CommunicateToFragment{
//Job of ViewHolderActivity is to allow swiping between list and MainFragment/Fragment
TabLayout tablayout;
ViewPager viewPager;
List<HistoricalQuote> historicaldata;
Bundle bundle;
Adapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_holder);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
viewPager =(ViewPager)findViewById(R.id.viewpager);
tablayout= (TabLayout)findViewById(R.id.tabs);
tablayout.setupWithViewPager(viewPager);
setupViewPager(viewPager);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
}
//----------------------- Interface code-----------
#Override
public void communicateup(){
communicatedown();
//call communicate down STRAIGHT, since we call it from mainfrag
}
#Override
public void communicatedown(){
//This line works
ListFragment currentFragment =(ListFragment)adapter.instantiateItem(viewPager,1);
currentFragment.refreshUI();
}
private void setupViewPager(ViewPager viewPager) {
adapter = new Adapter(getSupportFragmentManager());
adapter.addFragment(new MainFragment(), "Add Stock");
adapter.addFragment(new ListFragment(), "Portfolio");
viewPager.setAdapter(adapter);
}
static class Adapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public Adapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
Frag A (MainFragment)
(https://github.com/EXJUSTICE/Investr/blob/master/app/src/main/java/com/xu/investo/MainFragment.java)
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
View view =inflater.inflate(R.layout.content_main,container,false);
stocknames = new ArrayList<String>();
stocktickers = new ArrayList<String>();
tinyDB = new TinyDB(getContext());
/*
menu.setDisplayShowHomeEnabled(true);
//menu.setLogo("INSERT LOGO HERE");
menu.setDisplayUseLogoEnabled(true);
menu.setTitle(" Stock Selector");
*/
fetch =(Button) view.findViewById(R.id.fetchBtn);
enterID =(EditText)view.findViewById(R.id.enterID);
display =(TextView)view.findViewById(R.id.display);
mCalendar = Calendar.getInstance();
clear = (Button)view.findViewById(R.id.clearportfolio);
fetch.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//TODO all the main page should do is add stocktickers and names to portfolio
//Fetch id and the dates
id =enterID.getText().toString();
/*to = Calendar.getInstance();
from = Calendar.getInstance();
to.setTime(dateto);
from.setTime(datefrom);
*/
FetchXDayData getData = new FetchXDayData();
getData.execute(id);
}
});
clear.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view) {
tinyDB.clear();
recyclerinterface.communicateup();
}
});
return view;
}
//----------------------------INTERFACE CODE
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// This makes sure that the container activity has implemented
// the callback interface. If not, it throws an exception
try {
recyclerinterface = (CommunicateToActivity) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement RecyclerUpdateInterface");
}
}
///-------End of Oncreate---------------------------------------------------------------
//Called by AsyncTask, moving result to main thread
public void moveResultToUI(Stock result){
this.stock = result;
Toast.makeText(getActivity(),"Stock "+stock.getName()+" successfully added to portofolio",Toast.LENGTH_LONG).show();
//reverse the list of course, stock names and tickrs to portfolio
stocknames.add(stock.getName());
stocktickers.add(stock.getSymbol());
/*DEBUG Test code, Test. 30012017 WORKS
for (int i =0;i<historicaldata.size();i++){
HistoricalQuote current = historicaldata.get(i);
Toast toast = Toast.makeText(this,current.getClose().toString(),Toast.LENGTH_SHORT);
toast.show();
}
*/
//
if (stock != null){
display.setText("Name: "+stock.getName() +"\n"+"Price: "+ stock.getQuote().getPrice()+"\n"+ "Change(%)"+stock.getQuote().getChangeInPercent());
/*SMA = getSMA(10);
decision=checkSimpleCrossover(SMA,stock.getQuote().getPrice().longValue());
decisionView.setText("SMA: " + SMA + "\n"+decision);
*/
tinyDB.putListString("names",stocknames);
tinyDB.putListString("tickers",stocktickers);
//call interface activity comming up to Activity, then down to next fragment
recyclerinterface.communicateup();
}else{
Toast error = Toast.makeText(getActivity(),"Network Problem",Toast.LENGTH_SHORT);
error.show();
}
}
Frag B (ListFragment)
(https://github.com/EXJUSTICE/Investr/blob/master/app/src/main/java/com/xu/investo/ListFragment.java)
public class ListFragment extends Fragment {
private HistoricalQuote[] hisstocks;
private Stock[] stocks;
private RecyclerView recyclerView;
private StockAdapter mAdapter;
public ArrayList<String> stocknames;
public ArrayList<String>stocktickers;
TinyDB tinyDB;
#Override
public void onCreate(Bundle savedInstanceState){
//exists only to set the options menu
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
//fetching arraylists
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.content_list, container, false);
//Convert the arraylist into an array for arrayadapter
stocknames = new ArrayList<String>();
stocktickers = new ArrayList<String>();
tinyDB = new TinyDB(getContext());
stocknames = tinyDB.getListString("names");
stocktickers= tinyDB.getListString("tickers");
if (!stocknames.isEmpty()){
for (int i =0;i<stocknames.size();i++){
Toast toast= Toast.makeText(getActivity(),stocknames.get(i),Toast.LENGTH_SHORT);
toast.show();
}
}
recyclerView = (RecyclerView)view.findViewById(R.id.recylerView);
recyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), DividerItemDecoration.HORIZONTAL));
//http://stackoverflow.com/questions/24618829/how-to-add-dividers-and-spaces-between-items-in-recyclerview
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.setItemAnimator(new DefaultItemAnimator());
//layoutManager necessary because it positions views on screen, in this case linearly
if (stocknames.isEmpty() ||stocknames ==null){
recyclerView.setVisibility(View.GONE);
}else{
updateUI();
}
return view;
}
public void refreshUI(){
stocknames.clear();
stocktickers.clear();
stocknames = tinyDB.getListString("names");
stocktickers= tinyDB.getListString("tickers");
if (mAdapter == null) {
mAdapter = new StockAdapter(stocknames,stocktickers);
recyclerView.setAdapter(mAdapter);
} else {
recyclerView.invalidate();
mAdapter.notifyDataSetChanged();
}
}
public void updateUI() {
//updateUI must be called EXPLICITLY!
stocknames = tinyDB.getListString("names");
stocktickers= tinyDB.getListString("tickers");
if (mAdapter == null) {
mAdapter = new StockAdapter(stocknames,stocktickers);
recyclerView.setAdapter(mAdapter);
} else {
mAdapter.notifyDataSetChanged();
}
}
private class StockAdapter extends RecyclerView.Adapter<StockHolder>{
private ArrayList<String>stocknames;
private ArrayList<String>stocktickers;
public StockAdapter(ArrayList<String>names,ArrayList<String> tickers){
this.stocknames=names;
this.stocktickers=tickers;
}
#Override
public StockHolder onCreateViewHolder(ViewGroup parent, int viewType){
LayoutInflater layoutinflater = LayoutInflater.from(getActivity());
View view= layoutinflater.inflate(R.layout.row,parent,false);
return new StockHolder (view);
}
//Bind datato stockholder depending on position in arraylist
public void onBindViewHolder(StockHolder holder, int position){
String stockname = stocknames.get(position);
String stockticker =stocktickers.get(position);
holder.bindStock(stockname,stockticker);
}
#Override
public int getItemCount (){
return stocknames.size();
}
}
private class StockHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
private String stockname;
private String stockticker;
private TextView nametextView;
private TextView tickertextView;
public StockHolder(View itemView){
super(itemView);
itemView.setOnClickListener(this);
nametextView =(TextView)itemView.findViewById(R.id.name);
tickertextView= (TextView)itemView.findViewById(R.id.ticker);
}
#Override
public void onClick(View v){
Intent launchGraph= new Intent(v.getContext(),GraphActivity.class);
launchGraph.putExtra("stockticker",stockticker);
launchGraph.putExtra("stockname",stockname);
startActivity(launchGraph);
//Animations?
}
//Actual binder method, maybe add a current
public void bindStock(String stocknom, String stocktick){
this.stockname=stocknom;
this.stockticker = stocktick;
nametextView.setText(stockname);
tickertextView.setText(stockticker);
}
}
Thanks in advance.
EDIT: Solved issue by creating a new adapter and linking it to new arraylists pulled from the TinyDB, thereby effectively swapping adapters.

Solved the issue by creating a whole new RecyclerView adapter, to which new arraylist data was binded to, and the whole recyclerview was then set to use this new adapter. All of this was done in a single step from FragA, using interfaces shown in the code in the solution.
Method shown below:
public void refreshUI(){
tinyDB = null;
tinyDB = new TinyDB(getContext());
newnames = tinyDB.getListString("names");
newtickers= tinyDB.getListString("tickers");
mAdapter = new StockAdapter(newnames,newtickers);
recyclerView.setAdapter(mAdapter);
}

RecyclerView items disappear after switching between fragments

I have 4 fragments in my app, which managed in NavActivity:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_nav);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
fab = (FloatingActionButton) findViewById(R.id.fab);
// Fab for fragments
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrollStateChanged(int state) {
switch (state) {
case ViewPager.SCROLL_STATE_DRAGGING:
case ViewPager.SCROLL_STATE_SETTLING:
fab.hide(); // Hide animation
break;
case ViewPager.SCROLL_STATE_IDLE:
switch (viewPager.getCurrentItem()) {
case 0:
fragment1.shareFab(fab);
case 1:
fragment2.shareFab(fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(NavActivity.this, MapsActivity.class));
}
});
break;
default:
fragment1.shareFab(null);
break;
}
if(viewPager.getCurrentItem() == 0 || viewPager.getCurrentItem() == 1)
fab.show(); // Show animation
break;
}
}
});
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
tabLayout.setupWithViewPager(viewPager);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new MainFragment(), "Main");
adapter.addFragment(new AboutFragment(), "About");
adapter.addFragment(new CartFragment(), "Cart");
adapter.addFragment(new CatalogFragment(), "Catalog");
viewPager.setAdapter(adapter);
}
///////////new class
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
List<Fragment> fragments = getSupportFragmentManager().getFragments();
if (fragments != null) {
for (Fragment fragment : fragments) {
fragment.onRequestPermissionsResult(requestCode, permissions, grantResults);
}
}
}
}
I face one problem, items disappear after switching between fragments i think the implement with RecyclerView And the viewHolder has something to do with it.
Im trying to fetch data with volley from my server, into fragment C (frag num 3), the data streams well everything show correctly.
If i swap to frag B(frag num 2) or D(frag num 4), still everything works.
But if ill swap to frag A(frag num 1) and back to frag 3(where is my list item),
everything goes away, i get blank screen, even if i swap up and down still the items wont download again.
Here is Frag num 3 with my RecyclerView:
private FloatingActionButton mSharedFab;
private List<MyProducts> productsList;
//Creating Views
private RecyclerView recyclerView;
private RecyclerView.LayoutManager layoutManager;
private RecyclerView.Adapter adapter;
//Volley Request Queue
private RequestQueue requestQueue;
private int requestCount = 1;
private static final String URL_INDEX = "http://myserverip/android/product.php?page=";
//Tag values to read from json
public static final String TAG_IMAGE_URL = "product_img";
public static final String TAG_PRODUCT_SN = "product_serial_num";
public static final String TAG_PRODUCT_TITLE = "product_title";
public static final String TAG_PRODUCT_PRICE = "product_price";
public static final String TAG_PRODUCT_DESCRIPTION = "product_description";
public CartFragment() {
// Required empty public constructor
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_cart, container, false);
recyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);
layoutManager = new LinearLayoutManager(getActivity().getApplicationContext(), LinearLayoutManager.VERTICAL, false);
recyclerView.setLayoutManager(layoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setHasFixedSize(true);
//Initializing our superheroes list
productsList = new ArrayList<>();
requestQueue = Volley.newRequestQueue(getActivity().getApplicationContext());
//Calling method to get data to fetch data
getData();
//Adding an scroll change listener to recyclerview
if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.LOLLIPOP)
{
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener()
{
#Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (isLastItemDisplaying(recyclerView)) {
getData();
}
}
});
}
else
{
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
{
recyclerView.setOnScrollChangeListener( new RecyclerView.OnScrollChangeListener()
{
#Override
public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
if (isLastItemDisplaying(recyclerView)) {
getData();
}
}
});
}
}
//initializing our adapter
adapter = new CustomAdapter(productsList, getActivity());
//Adding adapter to recyclerview
recyclerView.setAdapter(adapter);
return view ;
}
and the customAdapter class:
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {
//Imageloader to load image
private ImageLoader imageLoader;
private Context context;
List<MyProducts> myProducts;
public CustomAdapter(List<MyProducts> myProducts, Context context)
{
super();
this.myProducts = myProducts;
this.context = context;
}
#Override
public CustomAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.product_list, parent, false);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
#Override
public void onBindViewHolder(CustomAdapter.ViewHolder holder, int position) {
if( myProducts != null) {
MyProducts myProducts1 = myProducts.get(position);
imageLoader = ImageVolley.getInstance(context).getImageLoader();
imageLoader.get(myProducts1.getProductImage(), ImageLoader.getImageListener(holder.imageView, R.drawable.android_store_log, android.R.drawable.ic_dialog_alert));
//Showing data to the views
holder.imageView.setImageUrl(myProducts1.getProductImage(), imageLoader);
holder.textViewProductTitle.setText(myProducts1.getProductTitle());
holder.textViewProductDescription.setText(myProducts1.getProductDescription());
holder.textViewProductSerialNumber.setText(myProducts1.getProductSn());
holder.textViewProductPrice.setText(myProducts1.getProductPrice());
}
}
#Override
public int getItemCount() {
return myProducts.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
//Views
public NetworkImageView imageView;
public TextView textViewProductTitle;
public TextView textViewProductDescription;
public TextView textViewProductSerialNumber;
public TextView textViewProductPrice;
//Initializing Views
public ViewHolder(View itemView) {
super(itemView);
imageView = (NetworkImageView) itemView.findViewById(R.id.imageViewHero);
textViewProductTitle = (TextView) itemView.findViewById(R.id.textViewProductTitle);
textViewProductDescription = (TextView) itemView.findViewById(R.id.textViewProductDescription);
textViewProductSerialNumber = (TextView) itemView.findViewById(R.id.textViewProductSerialNumber);
textViewProductPrice = (TextView) itemView.findViewById(R.id.textViewProductPrice);
}
}

Try this:
viewPager.setOffscreenPageLimit(3);
Set the number of pages that should be retained to either side of the current page in the view hierarchy in an idle state. Pages beyond this limit will be recreated from the adapter when needed.
setOffscreenPageLimit

Sending data from activity to fragment using set methods

I've posted a question regarding of passing data from activity to a fragment. And I've learnt that implementing Parcelable to a POJO class is a right way of doing it. After some research I also understand that in order to pass data to a fragment should use Bundle instead of Intent.
My previous question -->
Using same fragments but different content in Android
But now, my question is, what should I do in order to display a list of details (name, address, phone) using set methods when the cardview is clicked?
To be clear, what I want is
When first restaurant is clicked, the new intent that contains details fragment will be started. Inside the details fragment, it will display the restaurant name, address and phone of the first restaurant.
Can anyone guide me by showing me the code of two set of different details when two different restaurant cardview is clicked?
RestaurantListAdapter.java
I want to use if else statement under onClick, to display different details when different cardview is clicked
public class RestaurantListAdapter extends RecyclerView.Adapter<RestaurantListAdapter.ViewHolder> {
List<RestaurantList_Item> items;
private static ClickListener clickListener;
private Context context;
public RestaurantListAdapter(){
super();
items = new ArrayList<RestaurantList_Item>();
// POSITION 1
RestaurantList_Item restaurant = new RestaurantList_Item();
restaurant.setrImage(R.mipmap.img_anjappar);
restaurant.setrName("Anjappar Indian Chettinad Restaurant");
restaurant.setrCuisine("Indian");
items.add(restaurant);
// POSITION 2
restaurant = new RestaurantList_Item();
restaurant.setrImage(R.mipmap.img_morganfield);
restaurant.setrName("Morganfield");
restaurant.setrCuisine("Western");
items.add(restaurant);
// POSITION 3
restaurant = new RestaurantList_Item();
restaurant.setrImage(R.mipmap.img_nandos);
restaurant.setrName("Nando's");
restaurant.setrCuisine("Western");
items.add(restaurant);
// POSITION 4
restaurant = new RestaurantList_Item();
restaurant.setrImage(R.mipmap.img_shellout);
restaurant.setrName("Shellout");
restaurant.setrCuisine("Seafood");
items.add(restaurant);
// POSITION 5
restaurant = new RestaurantList_Item();
restaurant.setrImage(R.mipmap.img_beyond);
restaurant.setrName("Beyond Veggie");
restaurant.setrCuisine("Vegetarian");
items.add(restaurant);
// POSITION 6
restaurant = new RestaurantList_Item();
restaurant.setrImage(R.mipmap.img_myelephant);
restaurant.setrName("My Elephant");
restaurant.setrCuisine("Thai");
items.add(restaurant);
// POSITION 7
restaurant = new RestaurantList_Item();
restaurant.setrImage(R.mipmap.img_padangkota);
restaurant.setrName("Nasi Kandar Padang Kota");
restaurant.setrCuisine("Mamak");
items.add(restaurant);
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
View v = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.cardview_restaurant, viewGroup, false);
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
#Override
public void onBindViewHolder(final ViewHolder viewHolder, final int position) {
final RestaurantList_Item restaurant = items.get(position);
viewHolder.resImage.setImageResource(restaurant.getrImage());
viewHolder.restaurantName.setText(restaurant.getrName());
viewHolder.cuisine.setText(restaurant.getrCuisine());
viewHolder.itemView.setOnClickListener( new View.OnClickListener() {
#Override
public void onClick(View v) {
Context context = v.getContext();
// Toast.makeText(context, "Item clicked with position " +position, Toast.LENGTH_LONG).show();
if(position == 0){
Intent i = new Intent(context, Restaurant.class);
context.startActivity(i);
}
}
});
}
#Override
public int getItemCount() {
return items.size();
}
#Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
}
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
public ImageView resImage;
public TextView restaurantName;
public TextView cuisine;
public ViewHolder(final View itemView) {
super(itemView);
resImage = (ImageView) itemView.findViewById(R.id.resImage);
restaurantName = (TextView) itemView.findViewById(R.id.restaurantName);
cuisine = (TextView) itemView.findViewById(R.id.cuisine);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View v) {
clickListener.onItemClick(getAdapterPosition(), v);
}
}
public void setOnItemClickListener (ClickListener clickListener){
RestaurantListAdapter.clickListener = clickListener;
}
public interface ClickListener{
void onItemClick (int position, View v);
}
}
RestaurantModel.java
This is the POJO class that contains get set methods, I want to use the set methods to display restaurant details
public class RestaurantModel implements Parcelable{
//empty constructor
public RestaurantModel(){}
//A constructor that initializes the Restaurant object
public RestaurantModel(String resName, String resAddress, String resPhone, String resCuisine, String resPriceRange){
this.resName = resName;
this.resAddress =resAddress;
this.resPhone = resPhone;
this.resCuisine = resCuisine;
this.resPriceRange = resPriceRange;
}
//Parcelling the object
public RestaurantModel(Parcel in){
String[] data = new String [5];
in.readStringArray(data);
this.resName = data[0];
this.resAddress = data[1];
this.resPhone = data[2];
this.resCuisine = data[3];
this.resPriceRange = data[4];
}
// variable main photo
private int mainImage;
//variables for details fragment
private String resName, resAddress, resPhone, resCuisine, resPriceRange;
//variables for menu fragment
private int foodPhoto;
private String foodPrice, foodDescription;
/*get set methods*/
public int getMainImage(){
return mainImage;
}
public void setMainImage(int mainImage){
this.mainImage = mainImage;
}
public String getResName(){
return resName;
}
public void setResName(String resName){
this.resName = resName;
}
public String getResAddress(){return resAddress;}
public void setResAddress(String resAddress){this.resAddress = resAddress;}
public String getResPhone(){return resPhone;}
public void setResPhone(String resPhone){this.resPhone = resPhone;}
public String getResCuisine(){return resCuisine;}
public void setResCuisine(String resCuisine){this.resCuisine = resCuisine;}
public String getResPriceRange(){return resPriceRange;}
public void setResPriceRange(String resPriceRange){this.resPriceRange = resPriceRange;}
public int getFoodPhoto(){return foodPhoto;}
public void setFoodPhoto(int foodPhoto){this.foodPhoto = foodPhoto;}
public String getFoodDescription(){return foodDescription;}
public void setFoodDescription(String foodDescription){this.foodDescription = foodDescription;}
public String getFoodPrice(){return foodPrice;}
public void setFoodPrice(String foodPrice){this.foodPrice = foodPrice;}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeStringArray(new String[]{
this.resName,this.resAddress,this.resPhone, this.resCuisine, this.resPriceRange
});
}
// Creator
public static final Parcelable.Creator<RestaurantModel> CREATOR = new Parcelable.Creator<RestaurantModel>(){
#Override
public RestaurantModel createFromParcel(Parcel source) {
return new RestaurantModel(source);
}
#Override
public RestaurantModel[] newArray(int size) {
return new RestaurantModel[size];
}
};
}
Restaurant.java
This activity contains the fragments that will be shown when the cardview is clicked
public class Restaurant extends AppCompatActivity {
private TabLayout tabLayout;
private ViewPager viewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_restaurant);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
}
private void setupViewPager(ViewPager viewPager){
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new details(), "Details");
adapter.addFragment(new menu(), "Menu");
adapter.addFragment(new tableBooking(), "Table booking");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter{
private final List<Fragment> fragmentList = new ArrayList<>();
private final List<String> fragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager){
super(manager);
}
#Override
public Fragment getItem(int position) {
return fragmentList.get(position);
}
#Override
public int getCount() {
return fragmentList.size();
}
public void addFragment (Fragment fragment, String title){
fragmentList.add(fragment);
fragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return fragmentTitleList.get(position);
}
}
}
Details.java
This class extends fragment that contains restaurant details such as name, address and phone
public class details extends Fragment {
private TextView resName, resAddress, resPhone, resCuisine, resPriceRange;
public details() {
// Required empty public constructor
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
/* resName = (TextView) getView().findViewById (R.id.resName);
resAddress = (TextView) getView().findViewById (R.id.resAddress);
resPhone = (TextView) getView().findViewById (R.id.resPhone);
resCuisine = (TextView) getView().findViewById (R.id.resCuisine);
resPriceRange = (TextView) getView().findViewById (R.id.resPriceRange);*/
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_details, container, false);
}
}
Homepage.java
public class Homepage extends Activity {
RecyclerView recyclerView;
RecyclerView.LayoutManager llm;
RecyclerView.Adapter adapter;
private static final String TAG = Homepage.class.getSimpleName();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//super.onCreateDrawer(R.layout.activity_homepage);
setContentView(R.layout.activity_homepage);
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
llm = new LinearLayoutManager(Homepage.this);
recyclerView.setLayoutManager(llm);
adapter = new RestaurantListAdapter();
recyclerView.setAdapter(adapter);
}
}
EDIT: I'm not sure if I'm doing this correctly. I created multiple arraylist that describes different details for different restaurant. I put the code at onClick methods in RestaurantListAdapter.
#Override
public void onBindViewHolder(final ViewHolder viewHolder, final int position) {
final RestaurantList_Item restaurant = items.get(position);
viewHolder.resImage.setImageResource(restaurant.getrImage());
viewHolder.restaurantName.setText(restaurant.getrName());
viewHolder.cuisine.setText(restaurant.getrCuisine());
viewHolder.itemView.setOnClickListener( new View.OnClickListener() {
#Override
public void onClick(View v) {
Context context = v.getContext();
RestaurantModel rAnjappar = new RestaurantModel();
details fragment = new details();
Intent i = new Intent(context, Restaurant.class);
// Array List
ArrayList<RestaurantModel> a1 = new ArrayList<RestaurantModel>();
rAnjappar.setResName("Anjappar");
rAnjappar.setResAddress("Bandar Kinrara");
rAnjappar.setResPhone("03-80807362");
rAnjappar.setResCuisine("Mamak");
rAnjappar.setResPriceRange("RM 30 for 2 person");
ArrayList<RestaurantModel> a2 = new ArrayList<RestaurantModel>();
rAnjappar.setResName("Morganfield");
rAnjappar.setResAddress("Bandar Utama");
rAnjappar.setResPhone("03-80807362");
rAnjappar.setResCuisine("Western");
rAnjappar.setResPriceRange("RM 60 for 2 person");
// action when card view is clicked
if(position == 0){
Bundle b1 = new Bundle();
b1.putParcelableArrayList("anjappar", a1);
fragment.setArguments(b1);
context.startActivity(i);
}
}
});
}
If this is acceptable, next thing I should do is retrieve the bundle in my fragment code right? But since I will be having multiple bundles, how am I supposed to retrieve all the bundles in a correct way?

Ok so from as far as i understand you can do following things
1 Add this method in Adapter
public RestaurantList_Item getItem(int pos) {
return items.get(pos);
}
2. Homepage is your clicklistner activity (Hope so) in it
public void onItemClick(int position, view v) {
RestaurantList_Item row_object = adapter.getItem(position);
Intent i = new Intent(context, Restaurant.class);
i.putExtra(Common.Data_Object, row_object);
startActivity(i);
}
3. Replace code of Restaurant class
public class Restaurant extends AppCompatActivity {
private TabLayout tabLayout;
private ViewPager viewPager;
private RestaurantList_Item row_object;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_restaurant);
getIntentData(getIntent());
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
}
private void getIntentData(Intent i) {
if (i != null) {
row_object = i.getParcelableExtra(Common.Data_Object);
}
}
private void setupViewPager(ViewPager viewPager){
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
Fragment f = new details();
Bundle arguments = new Bundle();
arguments.putParcelable(Common.Data_Object, row_object);
f.setArguments(arguments);
adapter.addFragment(f, "Details");
adapter.addFragment(new menu(), "Menu");
adapter.addFragment(new tableBooking(), "Table booking");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter{
private final List<Fragment> fragmentList = new ArrayList<>();
private final List<String> fragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager){
super(manager);
}
#Override
public Fragment getItem(int position) {
return fragmentList.get(position);
}
#Override
public int getCount() {
return fragmentList.size();
}
public void addFragment (Fragment fragment, String title){
fragmentList.add(fragment);
fragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return fragmentTitleList.get(position);
}
}
}
4. get object from bundle in Detail fragment
private void getIntentData(Bundle b)
{
if (b != null)
{
detailObject = b.getParcelable(Common.Data_Object);
}
}
Hope it will help.

You can use setArguments() method of the fragment to pass your restaurant model class to new fragment while creating the new instance of it.You can get it back using getArguments() in newly created fragment's onCreate() method. You have to make your resturantModel.java class Serializable.
public class RestaurantModel implements Serializable{
...
}
Add data:-
Bundle bundle = new Bundle();
bundle.putSerializable("restaurant", restaurant);
Fragment1 frag1 = new Fragment1();
frag1.setArguments(bundle);
Get data :-
RestauranModel restaurant = (RestauranModel) getArguments().getSerializable("restaurant");
FYI: Difference between Parcelable and Serializable : https://stackoverflow.com/a/3323554/4690731