Intent intent = new Intent(this, PostSearch.class);
    intent.putExtra(PostSearch.EXTRA_POST_TYPE, postType);

    startActivityForResult(intent, RC_NEW_POST);

public class PostSearchAdapter extends RecyclerView.Adapter<PostSearchAdapter.PostSearchViewHolder> {

    private Context mContext;
    private int mSearchType;
    private List<?> mSearchResults;

    public PostSearchAdapter(Context context, int searchType) {
        this.mContext = context;
        mSearchType = searchType;

        switch (mSearchType) {
            case 0:
                mSearchResults = new ArrayList<Track>();
                break;
            case 1:
                mSearchResults = new ArrayList<Album>();
                break;
            case 2:
                mSearchResults = new ArrayList<Album>();
                break;
            default:
                Log.i(TAG, "Invalid search type for adapter. Uh oh...");
                break;
        }
    }

    @Override
    public int getItemCount() {
        if (mSearchResults == null) {
            return 0;
        } else {
            return mSearchResults.size();
        }
    }

    @NonNull
    @Override
    public PostSearchViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View searchResult = LayoutInflater
                                .from(parent.getContext())
                                .inflate(R.layout.list_item_search_result, parent, false);

        return new PostSearchViewHolder(searchResult);
    }

    @Override
    public void onBindViewHolder(PostSearchViewHolder viewHolder, int position) {
        switch (mSearchType) {
            case 0:
                Track track = (Track) mSearchResults.get(position);

                viewHolder.mTitle.setText(track.getTitle());
                viewHolder.mArtist.setText(track.getArtistNames());
                if (!TextUtils.isEmpty(track.getAlbum().getLargeAlbumCover())) {
                    Picasso.get()
                            .load(track.getAlbum().getLargeAlbumCover())
                            .error(R.drawable.ic_no_cover)
                            .into(viewHolder.mCover);
                }
                break;

            case 1:
                // Handle album results here
                break;

            case 2:
                // Handle artist results here
                break;

            default:
                break;
        }

    }

    public void addData(List<?> newData) {
        mSearchResults.add(newData);
        notifyDataSetChanged();
    }

    public void clearData(){
        mSearchResults.clear();
    }
}

mAdapter = new PostSearchAdapter(this, mSearchType);

private List<?> mSearchResults;

public PostSearchAdapter(Context context, int searchType) {
    this.mContext = context;
    mSearchType = searchType;

    switch (mSearchType) {
        //Instantiate mSearchResults here
    }
}

Track track = (Track) mSearchResults.get(position);