How to autoselect 1st item from RecyclerView?

Question

I have a recyclerView in my app that contain a list of Menu and when i press one of them if will change items in another recyclerView but when i open my activity noone of recyclerView where there are the menu's are selected.

So the question is how can i open the activity and find the 1st item of the recyclerView selected?

I was trying to simulate an click by Handler but it was making my app slower.

Here is the code from my Adapter :

public class RecyclerViewMenu extends RecyclerView.Adapter<RecyclerViewMenu.MenuViewHolder> {

    private ArrayList<MenuConstructor> menuConstructors;
    private OnItemClickListener onItemClickListener;
    private int selected_position = -1;



    public interface  OnItemClickListener {
        void onItemClick(int position);
    }

    public void setOnItemClickListener(OnItemClickListener listener){
        onItemClickListener = listener;
    }

    @NonNull
    @Override
    public MenuViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.menucard,parent,false);
        return new MenuViewHolder(v, onItemClickListener);

    }


    RecyclerViewMenu(ArrayList<MenuConstructor> menuList){
        menuConstructors = menuList;
    }

    @Override
    public void onBindViewHolder(@NonNull final MenuViewHolder holder, final int position) {
        MenuConstructor currentItem = menuConstructors.get(position);

        if (selected_position == position) {
            holder.itemView.setBackgroundColor(Color.parseColor("#2e7d32"));

        } else {
            holder.itemView.setBackgroundColor(Color.parseColor(currentItem.getSfondoColor()));
        }

        holder.textView.setText(currentItem.getDesk());
        holder.textView.setTextColor(Color.parseColor(currentItem.getFontColor()));




    }

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

    public class MenuViewHolder extends RecyclerView.ViewHolder {

        public TextView textView;

        MenuViewHolder(View itemView, final OnItemClickListener listener) {
            super(itemView);

            textView = itemView.findViewById(R.id.ButtonName);

            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                        if(listener != null){
                            int position = getAdapterPosition();
                            if (position != RecyclerView.NO_POSITION){
                                listener.onItemClick(position);
                                selected_position = position;
                                notifyDataSetChanged();
                            }
                        }


                }
            });



        }
    }

}

And here is a screenshot of my activity as you can see "CICCIO" is my first item of the recyclerView but it was selected manually.

Answer 1

Have you tried this in your activity:

recyclerView.findViewHolderForAdapterPosition(0).itemView.performClick()

Answer 2

The variable selected_position should be public in a Utils class and then you set selected_position = 0 in onCreate:

public class Utils {
    public static final int selected_position = -1;
}

then you use it in onCreate Utils.selected_position = 0; and in onBindViewHolder if (position == Utils.selected_position)

Of course you have to remove this line: private int selected_position = -1;