Basically i followed the accepted answer of this with few changes in my Activity and it worked perfect. My problem is that I wrote the exact same codes for my Fragment. when I open my app, it doesn't show anything. Before I changed my code in my fragment from a custom Adapter to the FirebaseRecyclerAdapter, everything worked fine.
This is my Fragment class
public class HomeFragment extends BaseFragment {
public Button buttonsrch, openFreezer, openRef, openPantry, scrollToFreezer, scrollToRef, scrollToPantry;
public NestedScrollView scrollView;
public RelativeLayout mFreezerLayout,mRefrigeratorLayout, mPantryLayout;
public FloatingActionButton mAddItems;
public DatabaseReference mDatabaseFreezer;
public RecyclerView mFreezerRecyclerView;
public ArrayList<Event> mDataSet;
private FirebaseRecyclerAdapter<Event, ProductHolder> firebaseRecyclerAdapter;
@Override
public int getLayoutResId() {
return R.layout.fragment_home;
}
@Override
public View inOnCreateView(View root, @Nullable ViewGroup container, Bundle savedInstancesState) {
View view = mRoot;
buttonsrch = view.findViewById(R.id.searchButton);
openPantry = view.findViewById(R.id.ShowMorePantry);
openRef = view.findViewById(R.id.ShowMoreRefrigerator);
openFreezer = view.findViewById(R.id.ShowMoreFreezer);
scrollToFreezer = view.findViewById(R.id.bringToFreezer);
scrollToPantry = view.findViewById(R.id.bringToPantry);
scrollToRef = view.findViewById(R.id.bringToRefrigerator);
scrollView = view.findViewById(R.id.scrollViewHomeFragment);
mFreezerLayout = view.findViewById(R.id.FreezerLayout);
mPantryLayout =view.findViewById(R.id.PantryRelativeLayout);
mRefrigeratorLayout = view.findViewById(R.id.RefrigeratorRelativeLayout);
mAddItems = view.findViewById(R.id.addItems_Inventory);
mAddItems.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(getActivity(), AddInventoryActivity.class));
}
});
buttonsrch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent i = new Intent(getActivity(), Search_Activity.class);
getActivity().startActivity(i);
}
});
openPantry.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent h = new Intent(getActivity(), PantryActivity.class);
getActivity().startActivity(h);
}
});
openRef.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent g = new Intent(getActivity(), RefActivity.class);
getActivity().startActivity(g);
}
});
openFreezer.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent s = new Intent(getActivity(), FreezerActivity.class);
getActivity().startActivity(s);
}
});
scrollToFreezer.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
FocusToFreezer();
}
});
scrollToRef.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
FocusToRef();
}
});
scrollToPantry.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
FocusToPantry();
}
});
mDataSet = new ArrayList<>();
mFreezerRecyclerView = view.findViewById(R.id.FreezerRecyclerView);
mFreezerRecyclerView.setHasFixedSize(true);
mFreezerRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
mDatabaseFreezer = FirebaseDatabase.getInstance().getReference().child("FreezerItems");
Query query = mDatabaseFreezer;
FirebaseRecyclerOptions<Event> firebaseRecyclerOptions = new FirebaseRecyclerOptions.Builder<Event>()
.setQuery(query, Event.class).build();
firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Event, ProductHolder>(firebaseRecyclerOptions) {
@Override
protected void onBindViewHolder(ProductHolder holder, int position, Event model) {
model = mDataSet.get(position);
holder.mItemName.setText(model.getName());
holder.mItemDate.setText(model.getDate());
final Event finalModel = model;
holder.mDeleteBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mDatabaseFreezer.child(finalModel.get_id()).removeValue();
}
});
}
@Override
public ProductHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recycler_view_row_inventory,parent,false);
return new ProductHolder(view);
}
};
mDatabaseFreezer.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
HashMap<String, String> value = (HashMap<String,String>) dataSnapshot.getValue();
if (value != null) {
String name = value.get("Name");
String date = value.get("Date");
String key = value.get("Key");
mDataSet.add(new Event(name,date,null, key));
Collections.sort(mDataSet, new Comparator<Event>() {
@Override
public int compare(Event event, Event t1) {
if (event.getDate() == null || t1.getDate() == null)
return 0;
return event.getDate().compareTo(t1.getDate());
}
});
}
}
@Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
@Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
@Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
mFreezerRecyclerView.setAdapter(firebaseRecyclerAdapter);
return root;
}
private class ProductHolder extends RecyclerView.ViewHolder{
private TextView mItemName, mItemDate;
private Button mDeleteBtn;
public ProductHolder(View itemView) {
super(itemView);
mItemName = itemView.findViewById(R.id.ItemNameTxtView);
mItemDate = itemView.findViewById(R.id.BestBeoforeTxtView);
mDeleteBtn = itemView.findViewById(R.id.deleteItem);
}
}
@Override
public void onStart() {
super.onStart();
firebaseRecyclerAdapter.startListening();
}
@Override
public void onStop() {
super.onStop();
if (firebaseRecyclerAdapter != null){
firebaseRecyclerAdapter.startListening();
}
}
private void FocusToFreezer(){
scrollView.post(new Runnable() {
@Override
public void run() {
scrollView.smoothScrollTo(0, mFreezerLayout.getTop());
}
});
}
private void FocusToRef(){
scrollView.post(new Runnable() {
@Override
public void run() {
scrollView.smoothScrollTo(0, mRefrigeratorLayout.getTop());
}
});
}
private void FocusToPantry(){
scrollView.post(new Runnable() {
@Override
public void run() {
scrollView.smoothScrollTo(0, mPantryLayout.getTop());
}
});
}
}
The only difference I could find is OnStart() and onStop() in activity are protected while on fragments are public
EDIT I found another page with the same problem and apparently FirebaseRecyclerAdapter doesn't work well with Fragments
