Ndtyjky

I used a working RecyclerView as a template for another, but I made some sort of mistake in its implementation and I can't find it. Here is the code that initializes the view:

 mMessageThreadList = new ArrayList<>();       

 mRecyclerView = findViewById(R.id.chat_list_recycler_view);





 private void initRecyclerView() {

        Log.d(TAG, "initRecyclerView Called");



        //Initializes and sets up adapter



        mAdapter = new ChatListRecyclerViewAdapter(mThreadList);

        mRecyclerView.setAdapter(mAdapter);





        Query query = mThreadCollection;

        query.addSnapshotListener(new EventListener<QuerySnapshot>() {

            @Override

            public void onEvent(@Nullable QuerySnapshot queryDocumentSnapshots, @Nullable FirebaseFirestoreException e) {



                for (DocumentChange documentChange : queryDocumentSnapshots.getDocumentChanges()) {

                    switch (documentChange.getType()) {

                        case ADDED:

                            Thread thread = documentChange.getDocument().toObject(Thread.class);

                            Log.d(TAG, "Last Message: " + thread.getLastMessage().getMessage());



                            mThreadList.add(thread);

                            mAdapter.notifyDataSetChanged();



                    }

                }

            }

        });

    }

Note that the print log statement in the SnapshotListener does contain a value when printed so the information is returning from Firebase, it's just not displaying. Which makes me think my problem is with my Adapter/Viewholder:

public class ChatListRecyclerViewAdapter extends RecyclerView.Adapter<ChatListRecyclerViewAdapter.ChatListViewHolder> {



    private List<Thread> threadList;



    ChatListRecyclerViewAdapter(List<Thread> threadList) {

        this.threadList = threadList;

    }





    @NonNull

    @Override

    public ChatListViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {



        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.chat_list_row, parent, false);

        return new ChatListViewHolder(view);



    }



    @Override

    public void onBindViewHolder(@NonNull ChatListViewHolder holder, int position) {



        // This method fills fields with data for each list item

        Log.d(TAG, "onBindViewholder called");



        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("MMM hh:mm a");

        final Thread thread = threadList.get(position);

        char initial = thread.getPartnerName().charAt(0);

        char uppercaseInitial = Character.toUpperCase(initial);



        Log.d(TAG, thread.getLastMessage() + " " + thread.getPartnerID());





        holder.partnerName.setText(thread.getPartnerName());

        holder.authorInitial.setText(uppercaseInitial);

        holder.lastMessageText.setText(thread.getLastMessage().getMessage());

        holder.lastMessageTime.setText(simpleDateFormat.format(thread.getLastMessage().getTimestamp()));



    }



    @Override

    public int getItemCount() {

        return threadList.size();

    }



    //Viewholder stores the information about the layout and content of each list item, and serves as a template for each item of a RecyclerView





    public class ChatListViewHolder extends RecyclerView.ViewHolder {



        TextView partnerName;

        TextView authorInitial;

        TextView lastMessageText;

        TextView lastMessageTime;

        LinearLayout listTextHolder;



        public ChatListViewHolder(View itemView) {

            super(itemView);



            partnerName = itemView.findViewById(R.id.partner_name);

            authorInitial = itemView.findViewById(R.id.partner_initial);

            lastMessageText = itemView.findViewById(R.id.last_message);

            lastMessageTime = itemView.findViewById(R.id.last_message_time);

            listTextHolder = itemView.findViewById(R.id.list_text_holder);



        }

    }

}

chat_list_row.xml file:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:id="@+id/single_thread_container"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:orientation="vertical"

    android:layout_marginTop="5dp"

    android:layout_marginBottom="5dp"

    android:background="@color/colorPrimaryDark">



    <TextView

        android:id="@+id/partner_initial"

        android:background="@drawable/chat_list_circle"

        android:layout_width="45dp"

        android:layout_height="45dp"

        android:layout_alignParentStart="true"

        android:gravity="center"

        android:text="A"

        android:textSize="36sp"

        tools:ignore="HardcodedText" />





    <TextView

        android:id="@+id/last_message_time"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentEnd="true"

        android:padding="5dp"

        android:fontFamily="@font/nunito_extralight"

        android:text="@string/sample_time"

        android:textColor="@android:color/darker_gray"

        android:textSize="12sp"

        android:typeface="normal" />



    <LinearLayout

        android:id="@+id/list_text_holder"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_toEndOf="@id/partner_initial"

        android:layout_centerVertical="true"

        android:orientation="vertical">



        <TextView

            android:id="@+id/partner_name"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:layout_gravity="start"

            android:layout_marginStart="5dp"

            android:fontFamily="@font/nunito"

            android:text="@string/sample_name"

            android:textColor="@color/white"

            android:textSize="14sp"

            android:textStyle="bold"

            android:typeface="sans" />



        <TextView

            android:id="@+id/last_message"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:layout_marginStart="5dp"

            android:fontFamily="@font/nunito_extralight"

            android:gravity="start"

            android:text="@string/sample_message"

            android:textColor="@android:color/darker_gray"

            android:textSize="12sp"

            android:typeface="normal" />



    </LinearLayout>



</RelativeLayout>

Edit: Layout of the Activity that RecyclerView appears in. I also edit above code to show where the variable is attached to the view:

<android.support.constraint.ConstraintLayout 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="fill_parent"

    android:layout_height="fill_parent"

    android:background="@color/colorPrimaryDark"

    android:paddingLeft="0dp"

    android:paddingTop="@dimen/activity_vertical_margin"

    android:paddingRight="0dp"

    android:paddingBottom="0dp"

    tools:context="org.andrewedgar.theo.ChatListActivity">



    <include

        android:id="@+id/chat_list_toolbar"

        layout="@layout/toolbar" />





    <android.support.v7.widget.RecyclerView

        android:id="@+id/chat_list_recycler_view"

        android:layout_width="0dp"

        android:layout_height="0dp"

        android:layout_alignParentStart="true"

        android:layout_centerVertical="true"

        app:layout_constraintBottom_toBottomOf="parent"

        app:layout_constraintEnd_toEndOf="parent"

        app:layout_constraintStart_toStartOf="parent"

        app:layout_constraintTop_toBottomOf="@+id/chat_list_toolbar" />



    <android.support.design.widget.FloatingActionButton

        android:id="@+id/new_check_in_button"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_gravity="end|bottom"

        android:layout_marginEnd="16dp"

        android:layout_marginBottom="16dp"

        android:src="@drawable/ic_person_pin_circle_black_24dp"

        app:layout_constraintBottom_toBottomOf="parent"

        app:layout_constraintEnd_toEndOf="parent" />





</android.support.constraint.ConstraintLayout>

Seems like you have missed to add layout manager of RecyclerView. Would you please add this and try again

RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());

recyclerView.setLayoutManager(mLayoutManager);

Your recyclerview is not showing any data because the list in adapter is still empty. After fetching data from firebase you are adding to mThreadList, which is still with activity and not adapter. To update the list in adapter you can add a method in adapter class and pass the list to adapter and notifyDataseChanged there.

Activity:

 //after firebase task...

 mAdapter.updateData(mThreadList);

Adapter: add new method

void updateData(List<Thread> threadList){

  this.threadList = threadList;

  notifyDatasetChanged();     //notify adapter that new list is added

}