Sum values of Recycler List item

Question

I need to get Total Value of Cart Products.Here I am using Recyclerview & Bean Class for get & set the listview items. I have tried to get.But while click increment / decrement button the getting values are not the correct value.

Let consider if my cart Product item value is Rs 100/- & Initial cart count as 1.

When I click increment button I am getting 200, 500, 900

When I click decrement button I am getting, 600, 400, 300

Here is my code.Please Check it.

Adapter Class:

            holder.ivIncrease.setOnClickListener(new View.OnClickListener() {

                public void onClick(View arg0) {
                    if (null != mListener) {
                        cartRes.get(position).CartCount = (bigInt + 1);
                        notifyItemChanged(position);
                        mListener.onListFragmentInteraction(holder.cartRess);
                    }
                    getIncreaseTotal();
                }
            });

            holder.ivDecrease.setOnClickListener(new View.OnClickListener() {

                public void onClick(View arg0) {
                    if (null != mListener) {
                        cartRes.get(position).CartCount = (bigInt - 1);
                        notifyItemChanged(position);
                        mListener.onListFragmentInteraction(holder.cartRess);

                    }
                    getDecreaseTotal();
                }
            });


  private void getDecreaseTotal() {
        for (int i = 0; i < cartRes.size() ; i++)
        {
            CartRes cartBasket = cartRes.get(i);
            System.out.println(cartBasket);
            totalPrice = cartBasket.getQuantity() * cartBasket.getPrice();
            sum -= totalPrice;
            Log.e("Total Sum", String.valueOf(sum));
        }
    }

    public void getIncreaseTotal() {
        for (int i = 0; i < cartRes.size() ; i++)
        {
            CartRes cartBasket = cartRes.get(i);
            System.out.println(cartBasket);
            totalPrice = cartBasket.getQuantity() * cartBasket.getPrice();
            sum += totalPrice;
            Log.e("Total Sum", String.valueOf(sum));
        }
    }

BeanClass:

public class CartRes {
    public String CartcategoryName;
    public String CartproductName;
    public String product_id;
    public int CartPrice;
    public int CartCount;
    private int Quantity;

    public CartRes(String product_idd, String productName, String categoryName, int cartCount, int cartPrice) {
        this.product_id = product_idd;
        this.CartproductName = productName;
        this.CartcategoryName = categoryName;
        this.CartCount = cartCount;
        this.CartPrice = cartPrice;
    }

    public CartRes() {
    }

    public int getPrice() {
        return CartPrice;
    }

    public int getQuantity() {
        return CartCount;
    }
}

Answer 1

Your problem may occur in your

totalPrice = cartBasket.getQuantity() * cartBasket.getPrice();

statement.

For example, If there is 1 product in your cart with price 200 and its quantity is also 1. So your total = 200 . Then you changed its quantity from 1 to 2.And what your doing is adding +1 to your quantity, so quantity became 2.By then you are multiplying its price 200 with quantity 2 so you are suppose to wrong here because you have already 200 added for 1 quantity in your "sum" variable.You have to only multiply it by 1 quantity and then add it into your "sum" variable.I think same happens in your decrement method too.