How to perfom query SQL IN clause in Firebase Android

Question

How do I query SQL IN clause in Firebase Android? I want to use it in a Firebase Recycler adapter to retrieve only some children based on some condition. Something like the foll

Answer 1

I found the solution: we cannot use FirebaseRecyclerAdapter. Instead we have to create custom adapter that extends RecyclerView.ViewHolder.

For passing values to this adapter, first we have to retrieve data using addValueEventListener and then we have to pass values to our adapter.

This is my code...

final ArrayList timelines = new ArrayList<>();

    mDatabaseTimeline.addChildEventListener(new ChildEventListener() {
        @Override
        public void onChildAdded(DataSnapshot dataSnapshot, String s) {

            final Timeline timeline = dataSnapshot.getValue(Timeline.class);

            if(timeline != null){

                mDatabaseFriends.child(mAuth.getCurrentUser().getUid()).child("active").addListenerForSingleValueEvent(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {

                        if (mAuth.getCurrentUser().getUid().equals(timeline.getUid()) || dataSnapshot.hasChild(timeline.getUid())) {

                            timelines.add(timeline);
                            mTimelineRecycler.setAdapter(new RecyclerAdapter(TimelineFragment.this.getContext(), timelines));

                        }
                    }

                    @Override
                    public void onCancelled(DatabaseError databaseError) {

                    }
                });
            }
        }

        @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) {

        }
    });

adapter----->

public class RecyclerAdapter extends RecyclerView.Adapter {

    Context context;
    ArrayList timeline;


    public RecyclerAdapter(Context context, ArrayList timeline) {
        this.context = context;
        this.timeline = timeline;



    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        LayoutInflater inflater = LayoutInflater.from(context);
        View row = inflater.inflate(R.layout.timeline_row, parent, false);
        TimelineViewHolder holder = new TimelineViewHolder(row);
        return holder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {


        final String post_key = timeline.get(position).getPostkey();

        ((TimelineViewHolder) holder).setUsername(timeline.get(position).getUsername());


 }

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

    public class TimelineViewHolder extends RecyclerView.ViewHolder {
        public TimelineViewHolder(View itemView) {
            super(itemView);

            view = itemView;
        }

        public View getView() {
            return view;
        }    

        public void setUsername(String username) {
            TextView usernameTxtView = (TextView) view.findViewById(R.id.timeline_username);
            usernameTxtView.setText(username);
        }

    }
}