Data from Firebase not displayed on RecyclerView

Question

I'm trying to display from data from my Firebase database but I'm getting the following: my recyclerview

Firebase database.

I've been looking up different solutions but I still keep returning to the same problem. I'm fairly new to Android and programming in general so any help would be appreciated. Here is the relevant code.

LogbookFragment:

public class LogbookFragment extends Fragment {

private TextView textView;
private CardView cardView;
private String assessment;
private String details;

private RecyclerView rv;
RequestQueue requestQueue;

private List<Assessment> skillsList = new ArrayList<>();

private static final String ARG_SECTION_NUMBER = "position";

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

public LogbookFragment() {
}

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

    Context context = getActivity();
    cardView = (CardView) rootView.findViewById(R.id.cv);
    rv = (RecyclerView) rootView.findViewById(R.id.rv);

    final LinearLayoutManager llm = new LinearLayoutManager(context);
    rv.setLayoutManager(llm);

    final RVAdapter adapter = new RVAdapter(skillsList);
    rv.setAdapter(adapter);

    initializeData();

    return rootView;
}

private void initializeData(){
    skillsList = new ArrayList<>();
    Firebase ref = new Firebase("https://athenajs.firebaseio.com/assessments");

    final RVAdapter adapter = new RVAdapter(skillsList);


    ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            System.out.println(dataSnapshot.getValue());

            for(DataSnapshot postSnapshot : dataSnapshot.getChildren()) {
                for (int i = 0; i<42; i++) {
                    assessment = postSnapshot.child("assessment").getChildren().toString();
                    details = postSnapshot.child("details").getChildren().toString();

                    skillsList.add(new Assessment(assessment, details));
                    rv.setAdapter(adapter);
                    adapter.notifyDataSetChanged();
                }

            }

        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {
            System.out.println("The read failed: " + firebaseError.getMessage());
        }
    });
}

}

RVAdapter:

public class RVAdapter extends RecyclerView.Adapter<RVAdapter.AssessViewHolder> {



public static class AssessViewHolder extends RecyclerView.ViewHolder {

    CardView cv;
    TextView assessName;
    TextView pracName;

    AssessViewHolder(View itemView) {
        super(itemView);
        cv = (CardView)itemView.findViewById(R.id.cv);
        assessName = (TextView)itemView.findViewById(R.id.assessment);
        pracName = (TextView) itemView.findViewById(R.id.details);

    }
}

List<Assessment> skill;

RVAdapter(List<Assessment> skills){
    this.skill = skills;
}

@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
    super.onAttachedToRecyclerView(recyclerView);
}

@Override
public AssessViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.itemlogbook, viewGroup, false);
    AssessViewHolder avh = new AssessViewHolder(v);
    return avh;
}

@Override
public void onBindViewHolder(AssessViewHolder assessViewHolder, int i) {
    assessViewHolder.assessName.setText(skill.get(i).assessment);
    assessViewHolder.pracName.setText(skill.get(i).details);
}

@Override
public int getItemCount() {
    return skill.size();

}

}

Assessment class:

public class Assessment {
String assessment;
String details;

Assessment(String assessment, String details) {
    this.assessment = assessment;
    this.details = details;

}

public String getAssessment() {
    return assessment;
}

public String getDetails() {
    return details;
}

Answer 1

As stated in the comments, The problem might be the fact that you only add data to the skillsList AFTER you had already initialized your adapter - and since the skillsList is empty at first, there's nothing to display. So since you are not actually change the underlying data but rather initializing the adapter with the first initial data - these are the changes you should make to your initializeData() method:

private void initializeData(){
    skillsList = new ArrayList<>();
    Firebase ref = new Firebase("https://athenajs.firebaseio.com/assessments/skills");

    ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            System.out.println(dataSnapshot.getValue());

            for(DataSnapshot postSnapshot : dataSnapshot.getChildren()) {
                for (int i = 0; i<42; i++) {
                    assessment = postSnapshot.child("assessment").getValue().toString();
                    details = postSnapshot.child("details").getValue().toString();
                    //here you add the assessment object to the list
                    skillsList.add(new Assessment(assessment, details));                    
                }

            }
            //at this point you have looped through all the "children" - 
            //now you are ready to initialize the adapter
            RVAdapter adapter = new RVAdapter(skillsList);
            rv.setAdapter(adapter));
            //commented out: no need to call this now - since you have not made any changes to the data
            //adapter.notifyDataSetChanged();
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {
            System.out.println("The read failed: " + firebaseError.getMessage());
        }
    });
}

I hope this helps. Give it a try and let me know.

Answer 2

I think these two lines here are causing the issue

 assessment = postSnapshot.child("assessment").getChildren().toString();
 details = postSnapshot.child("details").getChildren().toString();

As per firebase documents you should retrive your value by calling the

getValue() 

method not

toString();

As I don't know how your assesment and details data is . if it is a single value then

assessment = postSnapshot.child("assessment").getValue(String.class);
     details = postSnapshot.child("details")..getValue(String.class);

would do the trick.

For more information go here