Auto show item in recyclerview to another recyclerview?

Question

I making an app for tablet so it will have two recyclerview on one activity. What I want to do is when I click an item on first recyclerview, the item information will show automatically on another recyclerview as a list. But what actually my coding do is when I click the item, the item not show automatically on another recyclerview. When I exit the app and relaunch back, finally show the item on another recyclerview.

Actually I have tried put notifysetdatachanged but it still the same.

This MainActivity.java

private void displayItemPurchased() {
    itemList = new ArrayList<>();

    Cursor cursorItemPurchased = myDb.getItemPurchased();
    while (cursorItemPurchased.moveToNext()) {
        String itemId = cursorItemPurchased.getString(1);
        String itemDescription = cursorItemPurchased.getString(2);
        int itemQty = cursorItemPurchased.getInt(3);
        Double itemAmt = cursorItemPurchased.getDouble(4);
        String itemTimestamp = cursorItemPurchased.getString(5);

        Product_Item item = new Product_Item();
        item.setItemDescription(itemId);
        item.setItemDescription(itemDescription);
        item.setItemQty(itemQty);
        item.setItemAmt(itemAmt);
        item.setItemTimestamp(itemTimestamp);

        itemList.add(item);
    }

    adapterItemsList = new AdapterItemsList(getApplication(), itemList, cursorItemPurchased);
    rvList.setAdapter(adapterItemsList);
    adapterItemsList.notifyDataSetChanged();
}

This AdapterItem.java

public class AdapterItem extends RecyclerView.Adapter<AdapterItem.MyViewHolder> {

    private int row_index = -1;

    private ArrayList<Product_Item> itemsList;
    private Context ctx;
    private LayoutInflater inflater;

    //SQLite
    DatabaseHelper myDb;

    public AdapterItem(Context ctx, ArrayList<Product_Item> itemsList) {
        inflater = LayoutInflater.from(ctx);
        this.ctx = ctx;
        this.itemsList = itemsList;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.recycler_view_items_list, parent, false);

        myDb = new DatabaseHelper(ctx);

        return new MyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull final MyViewHolder holder, final int position) {

        Product_Item item = itemsList.get(position);
        final String id = item.getItemId();
        final String name = item.getItemDescription();
        final int qty = Integer.parseInt(holder.txtQty.getText().toString());
        final Double amt = item.getItemAmt();
        final String timestamp =  item.getItemTimestamp();

        holder.itemId_tv.setText(id);
        holder.itemName_tv.setText(name);
        holder.btnPlus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

            }
        });
        holder.btnMinus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

            }
        });
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                row_index = position;
                notifyDataSetChanged();
                myDb.insertItemPurchased(id, name, qty, amt, timestamp);
            }
        });

        if (row_index == position) {
            holder.layoutQTY.setVisibility(View.VISIBLE);
            holder.layoutQTY.setAnimation(holder.fromBottom);
        } else {
            holder.layoutQTY.setVisibility(View.INVISIBLE);
        }
    }

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

    public class MyViewHolder extends RecyclerView.ViewHolder {

        Animation fromBottom, fromTop;
        LinearLayout layoutQTY;
        TextView itemId_tv, itemName_tv,txtQty;
        ImageButton btnPlus,btnMinus;

        MyViewHolder(View itemView) {
            super(itemView);
            fromBottom = AnimationUtils.loadAnimation(ctx,R.anim.qtyfrombottom);
            fromTop = AnimationUtils.loadAnimation(ctx,R.anim.qtyfromtop);

            itemId_tv = itemView.findViewById(R.id.txtItemId);
            itemName_tv = itemView.findViewById(R.id.txtName);
            layoutQTY = itemView.findViewById(R.id.layoutQTY);
            txtQty = itemView.findViewById(R.id.txtQty);
            btnPlus = itemView.findViewById(R.id.btnPlus);
            btnMinus = itemView.findViewById(R.id.btnMinus);
        }
    }
}

And This AdapterItemList

public class AdapterItemsList extends RecyclerView.Adapter<AdapterItemsList.ItemListViewHolder> {

    private ArrayList<Product_Item> itemsList;
    private Context mContext;
    private Cursor mCursor;

    public AdapterItemsList(Context ctx, ArrayList<Product_Item> itemsList, Cursor cursor){
        mContext = ctx;
        this.itemsList = itemsList;
        mCursor = cursor;
    }

    public class ItemListViewHolder extends RecyclerView.ViewHolder{
        public TextView nameText;
        public TextView countText;
        public TextView priceText;

        public ItemListViewHolder(@NonNull View itemView) {
            super(itemView);

            nameText = itemView.findViewById(R.id.txtItemList);
            countText = itemView.findViewById(R.id.txtQty);
            priceText = itemView.findViewById(R.id.txtPriceItem);

        }
    }

    @NonNull
    @Override
    public ItemListViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        LayoutInflater inflater = LayoutInflater.from(mContext);
        View view = inflater.inflate(R.layout.recycler_view_pay_list_item,viewGroup,false);
        return new ItemListViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ItemListViewHolder holder, int position) {
        Product_Item item = itemsList.get(position);
        final String id = item.getItemId();
        final String name = item.getItemDescription();
        final int qty = item.getItemQty();
        final Double amt = item.getItemAmt();
        final String timestamp =  item.getItemTimestamp();

        holder.nameText.setText(name);
        holder.countText.setText(String.valueOf(qty));
        holder.priceText.setText(String.valueOf(amt));
    }

    @Override
    public int getItemCount() {
        return mCursor.getCount();
    }

    public void swapCursor (Cursor newCursor){
        if (mCursor != null){
            mCursor.close();
        }

        mCursor = newCursor;

        if (newCursor != null){
            notifyDataSetChanged();
        }
    }

Answer 1

If you want to add item to recylcerview , in your adding adapter do this : - Create a method :

public void addSingleProduct(Product_Item productItem){
   itemsList.add(productItem);
   notifyDataSetChanged();
}

But you need also to remove it from the other adapter where you already have it Create a method :

public void removeItem(Product_Item productItem){
   itemsList.remove(productItem)
   int position = itemsList.indexOf(productItem);
   notifyItemRemoved(position);
}

And than call the methods in where your adapter instance is , in your case the MainActivity.