RecyclerView is blank inside a fragment

Question

I have a tabbed activity where there are three tabs. The second tab should show users posts inside a RecyclerView from Firebase. The problem is that the tab in question appears to be just a blank white screen with no information. It should show every post from the Firebase which has the specific users-id and I have a query for it that I pass inside the FirebaseRecyclerAdapter. Any idea why the posts don't appear?

Here is the tabbed activity main java class:

private SectionsPagerAdapter mSectionsPagerAdapter;

/**
 * The {@link ViewPager} that will host the section contents.
 */
private ViewPager mViewPager;

private String thisPagesUsersId;
private String currentUidToUse;
private String tabTitles[] = new String[]{"Info", "Spots", "Likes"};

private FirebaseAuth firebaseAuth;
private DatabaseReference usersRef;

Toolbar toolbar;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_users_page);

    firebaseAuth = FirebaseAuth.getInstance();
    usersRef = FirebaseDatabase.getInstance().getReference().child("Users");

    toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    toolbar.setNavigationOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            finish();
        }
    });

    mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

    // Set up the ViewPager with the sections adapter.
    mViewPager = (ViewPager) findViewById(R.id.container);
    mViewPager.setAdapter(mSectionsPagerAdapter);

    TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(mViewPager);

    mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
    tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });


    //GETTING THE INFO WHOM INFO IS IN THIS PAGE
    if(getIntent().hasExtra("uid"))
    {
        thisPagesUsersId = getIntent().getExtras().get("uid").toString();
        currentUidToUse = thisPagesUsersId;

        changeToolbarTitle(currentUidToUse);

        UsersInfo fragmentInfo =  new UsersInfo();
        UsersSpots fragmentSpots = new UsersSpots();

        fragmentInfo.setName(thisPagesUsersId);
        fragmentSpots.setName(thisPagesUsersId);
    }
    else
    {
        currentUidToUse = firebaseAuth.getCurrentUser().getUid();

        changeToolbarTitle(currentUidToUse);

        UsersInfo fragmentInfo =  new UsersInfo();
        UsersSpots fragmentSpots = new UsersSpots();

        fragmentInfo.resetName();
        fragmentSpots.resetName();
    }
}


//SET TOOLBAR TITLE TO USER NAME THAT IS BEING SPECTATED
private void changeToolbarTitle(String uid)
{
    usersRef.child(uid).addValueEventListener(new ValueEventListener()
    {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot)
        {
            String currentUserName = dataSnapshot.child("username").getValue().toString();

            toolbar.setTitle(currentUserName);
        }

        @Override
        public void onCancelled(DatabaseError databaseError)
        {

        }
    });
}


@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_users_page, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item)
{
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings)
    {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment
{

    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    private static final String ARG_SECTION_NUMBER = "section_number";

    public PlaceholderFragment()
    {

    }

    /**
     * Returns a new instance of this fragment for the given section
     * number.
     */
    public static PlaceholderFragment newInstance(int sectionNumber)
    {
        PlaceholderFragment fragment = new PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        View rootView = rootView = inflater.inflate(R.layout.fragment_users_info, container, false);
        return rootView;
    }
}

/**
 * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
 * one of the sections/tabs/pages.
 */
public class SectionsPagerAdapter extends FragmentPagerAdapter
{

    public SectionsPagerAdapter(FragmentManager fm)
    {
        super(fm);
    }

    @Override
    public Fragment getItem(int position)
    {
        switch (position) {
            case 0:
                // Top Rated fragment activity
                return new UsersInfo();
            case 1:
                // Games fragment activity
                return new UsersSpots();
            case 2:
                // Movies fragment activity
                return new UsersLikes();
        }

        return null;
    }

    @Override
    public int getCount()
    {
        // Show 3 total pages.
        return 3;
    }

    @Override
    public CharSequence getPageTitle(int position)
    {
        return tabTitles[position];
    }
}

Here is the fragments java class where I try to show the posts:

RecyclerView spotsList;

FirebaseAuth firebaseAuth;
DatabaseReference postsRef, userReference, likesRef, seenRef;

public static String thisPagesUsersId = null;
private String currentUserId;

boolean detailsOpen;
boolean hasLiked = false;
boolean hasSeen = false;

private View mainView;


//GETTING THE USER WHOM INFO IS CURRENTLY IN THIS PAGE
public void setName(String string)
{
    thisPagesUsersId = string;
}


//RESET PREVIOUS USER IS USER WANTS TO SPECTATE HIS OWN ACCOUNT
public void resetName()
{
    thisPagesUsersId = null;
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState)
{
    mainView = inflater.inflate(R.layout.fragment_users_spots, container, false);

    firebaseAuth = FirebaseAuth.getInstance();
    currentUserId = firebaseAuth.getCurrentUser().getUid();
    postsRef = FirebaseDatabase.getInstance().getReference().child("Posts");
    userReference = FirebaseDatabase.getInstance().getReference().child("Users");
    likesRef = FirebaseDatabase.getInstance().getReference().child("Likes");
    seenRef = FirebaseDatabase.getInstance().getReference().child("Seen");

    spotsList = (RecyclerView)mainView.findViewById(R.id.usersSpotsRV);
    LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getContext());
    spotsList.setHasFixedSize(true);
    linearLayoutManager.setReverseLayout(true);
    linearLayoutManager.setStackFromEnd(true);
    spotsList.setLayoutManager(linearLayoutManager);

    // Inflate the layout for this fragment
    return mainView;
}


@Override
public void onStart()
{
    super.onStart();

    Query currentUserQuery = postsRef.orderByChild("userId").startAt(thisPagesUsersId).endAt(thisPagesUsersId + "\uf8ff");

    FirebaseRecyclerAdapter<Posts, postsViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Posts, postsViewHolder>
            (Posts.class, R.layout.spot_layout, postsViewHolder.class, currentUserQuery)
    {
        @Override
        protected void populateViewHolder(final postsViewHolder viewHolder, Posts model, int position)
        {
            final String postKey = getRef(position).getKey();

            final DatabaseReference currentPostRef = FirebaseDatabase.getInstance().getReference().child("Posts").child(postKey);

            viewHolder.setDetails(model.getDetails());
            viewHolder.setDate(model.getDate());
            viewHolder.setImage(model.getImage());
            viewHolder.setManufacturer(model.getManufacturer());
            viewHolder.setModel(model.getModel());
            viewHolder.setProfileImage(model.getProfileImage());
            viewHolder.setTime(model.getTime());
            viewHolder.setUsername(model.getUsername());

            viewHolder.setLikeButtonStatus(postKey);
            viewHolder.setSeenButtonStatus(postKey);
        }
    };

    spotsList.setAdapter(firebaseRecyclerAdapter);
}


public static class postsViewHolder extends RecyclerView.ViewHolder
{
    View mView;

    TextView detailsTextView;

    ImageView infoIW;
    ImageView menuDotsIW;
    ImageView locationIW;
    ImageView likeIW;
    ImageView seenIW;
    TextView likesAmountTV;
    TextView seenAmountTV;

    int likesCount;
    int seenCount;

    String currentUserId;

    DatabaseReference likesRef;
    DatabaseReference seenRef;

    public postsViewHolder(View itemView)
    {
        super(itemView);

        mView = itemView;

        detailsTextView = (TextView)mView.findViewById(R.id.postDetailTV);
        detailsTextView.setVisibility(View.GONE);
        infoIW = (ImageView)mView.findViewById(R.id.postInfoIW);
        menuDotsIW = (ImageView)mView.findViewById(R.id.menuDotsIW);
        locationIW = (ImageView)mView.findViewById(R.id.postLocateIW);
        likeIW = (ImageView)mView.findViewById(R.id.likeIW);
        seenIW = (ImageView)mView.findViewById(R.id.seenIW);
        likesAmountTV = (TextView)mView.findViewById(R.id.likesAmountTV);
        seenAmountTV = (TextView)mView.findViewById(R.id.seenTV);

        likesRef = FirebaseDatabase.getInstance().getReference().child("Likes");
        seenRef = FirebaseDatabase.getInstance().getReference().child("Seen");

        currentUserId = FirebaseAuth.getInstance().getCurrentUser().getUid();
    }


    //SET ALL THE TEXTS AND IMAGES
    public void setDate(String date)
    {
        TextView postDate = (TextView) mView.findViewById(R.id.postDateTV);
        postDate.setText(date);
    }


    public void setDetails(String details)
    {
        TextView details_text = (TextView) mView.findViewById(R.id.postDetailTV);
        details_text.setText(details);
    }

    public void setImage(String image)
    {
        ImageView profileImage = (ImageView) mView.findViewById(R.id.postTheImage);
        Picasso.get().load(image).into(profileImage);
    }

    public void setManufacturer(String manufacturer)
    {
        TextView manufact_name = (TextView) mView.findViewById(R.id.postManufactTV);
        manufact_name.setText(manufacturer);
    }

    public void setModel(String model)
    {
        TextView model_name = (TextView) mView.findViewById(R.id.postModelTV);
        model_name.setText(model);
    }

    public void setProfileImage(String profileImage)
    {
        CircleImageView profImage = (CircleImageView) mView.findViewById(R.id.postProfpicIW);
        Picasso.get().load(profileImage).into(profImage);
    }

    public void setTime(String time)
    {
        TextView postTime = (TextView) mView.findViewById(R.id.postTimeTV);
        postTime.setText(time);
    }

    public void setUsername(String username)
    {
        TextView user_name = (TextView) mView.findViewById(R.id.postUsernameTV);
        user_name.setText(username);
    }
}

Here is the xml for the fragment:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.aapotti.thecarapp.UsersSpots">

<!-- TODO: Update blank fragment layout -->

<android.support.v7.widget.RecyclerView
    android:id="@+id/usersSpotsRV"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

Answer 1

private void setUpFirebaseAdapter() {
    mFirebaseAdapter = new FirebaseRecyclerAdapter<Restaurant, FirebaseRestaurantViewHolder>
            (Restaurant.class, R.layout.restaurant_list_item, FirebaseRestaurantViewHolder.class, 
                mRestaurantReference) {

        @Override
        protected void populateViewHolder(FirebaseRestaurantViewHolder viewHolder, 
            Restaurant model, int position) {
            viewHolder.bindRestaurant(model);
        }
    };
    mRecyclerView.setHasFixedSize(true);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
    mRecyclerView.setAdapter(mFirebaseAdapter);
}

this is my code in onCreateView