Android - Firebase on data change refreshes the page

Question

I'm kinda newbie to Android. I have a recyclerview that I store in Firebase database. My recyclerview are made of cardviews. Inside each cardview I have a button that updates the node info in Firebase. Each time the above is happening, my page refreshes (I guess to load the new data).

My mainactivity code relevant code(called on onCreate) :

  private void loadRecyclerViewData() {

    databaseReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            if (posts.size() > 0) {
                posts.clear();
            }

            for (DataSnapshot ds : dataSnapshot.getChildren()) {
                Post post = ds.getValue(Post.class);
                //Getting a specific user's information (nickname purposes)
                if (post.getSubGenreType().equals(SubGenreString)) {
                    posts.add(post);
                    Collections.reverse(posts);
                }
            }
            adapter = new RecyclerAdapter(posts, getApplicationContext());
            recyclerView.setAdapter(adapter);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });


}

my adapter :

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {
public static Boolean isAyed = false;
private FirebaseAuth firebaseAuth;
private List<Post> posts;
private Context context;
private String userTryToAyeEmail;

public RecyclerAdapter(List<Post> posts, Context context) {
    this.posts = posts;
    this.context = context;
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    firebaseAuth = FirebaseAuth.getInstance();

    View v = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.recycle_card, parent, false);
    return new ViewHolder(v);
}

@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
    final Post post = posts.get(position);
    holder.imageButton.setVisibility(View.GONE);
    holder.editText.setVisibility(View.GONE);

    String colorString = post.getPostColor();
    int color = Color.parseColor(colorString);
    int newNumOfLikes = post.getPostLikes();
    int currentNumOfLikes = post.getPostLikes();
    // holder.cardView.setCardBackgroundColor(color);
    holder.textViewHead.setText(post.getPostContent());
    holder.textViewNickname.setText(post.getPostNickname());
    holder.textViewTimeStamp.setText(post.getPostTimeStamp());

    holder.ayeButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Boolean userLiked = false;
            if (firebaseAuth.getCurrentUser() != null) {
                String currentUserEmail = firebaseAuth.getCurrentUser().getEmail();
                List<String> currentLikedPost = post.getUserLikedList();
                for (int i = 0; i < currentLikedPost.size(); i++) {
                    if (currentUserEmail.equals(currentLikedPost.get(i))) {
                        currentLikedPost.remove(i);
                        int newNumOfLikes = post.getPostLikes() - 1;
                        updateLikes(post.getId(), newNumOfLikes, post.getPostNickname(), post.getPostTimeStamp(), post.getPostContent(), post.getPostColor(), post.getSubGenreType(), post.getUserLikedList());
                        userLiked = true;

                        break;
                    }
                }
                if (!userLiked) {
                    currentLikedPost.add(currentUserEmail);
                    int newNumOfLikes = post.getPostLikes() + 1;
                    updateLikes(post.getId(), newNumOfLikes, post.getPostNickname(), post.getPostTimeStamp(), post.getPostContent(), post.getPostColor(), post.getSubGenreType(), post.getUserLikedList());
                }
            }
        }
    });

    if (firebaseAuth.getCurrentUser() != null) {
        String currentUserEmail = firebaseAuth.getCurrentUser().getEmail();

        List<String> usersLikedPost = post.getUserLikedList();
        for (int i = 0; i < usersLikedPost.size(); i++) {
            if (currentUserEmail.equals(usersLikedPost.get(i))) {
                holder.ayeButton.setTextColor(Color.parseColor("#FF0000"));
                break;
            }

        }
    }

    holder.ayeTextView.setText(Integer.toString(newNumOfLikes));

    holder.cardView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent myIntent = new Intent(context, SinglePostActivity.class);
            myIntent.putExtra("postID", post.getId());
            myIntent.putExtra("postNickname", post.getPostNickname());
            myIntent.putExtra("postTimeStamp", post.getPostTimeStamp());
            myIntent.putExtra("postContent", post.getPostContent());
            myIntent.putExtra("postColor", post.getPostColor());
            context.startActivity(myIntent);

        }
    });
}

private void updateLikes(String id, int newNumOfLikes, String postNickname, String postTimeStamp, String postContent, String postColor, String SubGenre, List<String> userLikedPostList) {
    DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("posts").child(id);

    Post post = new Post(postColor, postContent, postNickname, postTimeStamp, id, newNumOfLikes, SubGenre, userLikedPostList);
    databaseReference.setValue(post);


}

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


public class ViewHolder extends RecyclerView.ViewHolder {

    public TextView textViewHead;
    public TextView textViewNickname;
    public TextView textViewTimeStamp;
    public TextView ayeButton;
    public TextView ayeTextView;
    public CardView cardView;
    public LinearLayout linearLayout;
    public EditText editText;
    public ImageButton imageButton;

    public ViewHolder(View itemView) {
        super(itemView);
        textViewHead = (TextView) itemView.findViewById(R.id.textViewHead);
        textViewNickname = (TextView) itemView.findViewById(R.id.textViewNickname);
        textViewTimeStamp = (TextView) itemView.findViewById(R.id.textViewTimeStamp);
        ayeButton = (TextView) itemView.findViewById(R.id.ayeButton);
        ayeTextView = (TextView) itemView.findViewById(R.id.ayeTextView);
        cardView = (CardView) itemView.findViewById(R.id.cardViewID);
        linearLayout = (LinearLayout) itemView.findViewById(R.id.cardLinearLayout);
        editText = (EditText) itemView.findViewById(R.id.addCommentEditText);
        imageButton = (ImageButton) itemView.findViewById(R.id.addCommentImageButton);

    }

}

}

I wish the page to stay in place, how can I do that ?? Thank you all.

Answer 1

Set your adapter in onCreate and notify it from onDataChange

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.your_layout);
    //initialize
    .
    .
    //set adapter
    adapter = new RecyclerAdapter(posts, getApplicationContext());
    recyclerView.setAdapter(adapter);
} 

private void loadRecyclerViewData() {

    databaseReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            if (posts.size() > 0) {
                posts.clear();
            }

            for (DataSnapshot ds : dataSnapshot.getChildren()) {
                Post post = ds.getValue(Post.class);
                //Getting a specific user's information (nickname purposes)
                if (post.getSubGenreType().equals(SubGenreString)) {
                    posts.add(post);
                    Collections.reverse(posts);
                }
            }
            adapter.notifyDataSetChanged(); //notify
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
}