java 安卓滑动并避免刷新recyclerview项

Question

我想计算一次总成本，而不是每次刷产品时重复计算

安卓滑动并避免刷新recyclerview项目

public class CartAdapter extends RecyclerView.Adapter<CartAdapter.ViewHolder> {
Context context;
List<CartModel> cartModels;
float total;
public CartAdapter(Context context, List<CartModel> cartModels) {
    this.context = context;
    this.cartModels = cartModels;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.cart_product_layout, parent, false));
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
    Glide.with(context).load(cartModels.get(position).getProductImg()).into(holder.productImg);
    holder.name.setText(cartModels.get(position).getProductName());
    holder.price.setText(cartModels.get(position).getProductPrice());
    holder.quantity.setText(String.valueOf(cartModels.get(position).getProductQuantity()));

    total += Float.parseFloat(String.valueOf(holder.price.getText()));

    Intent intent = new Intent("MyCart");
    intent.putExtra("total", total);
    LocalBroadcastManager.getInstance(context).sendBroadcast(intent);
}
@Override
public int getItemCount() {
    return cartModels.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
    ImageView productImg;
    TextView name, price, quantity;
    public ViewHolder(@NonNull View itemView) {
        super(itemView);
        productImg = itemView.findViewById(R.id.product_img);
        name = itemView.findViewById(R.id.product_name);
        price = itemView.findViewById(R.id.product_price);
        quantity = itemView.findViewById(R.id.product_quantity);
    }
}

}

显示刷卡前后屏幕的图片

Answer 1

您不应该在OnBindViewHolder（）中进行任何计算。当视图循环使用时，每次上下滚动时都会调用该函数。相反，我建议只计算适配器初始化时的总数

public CartAdapter(Context context, List<CartModel> cartModels) {
    this.context = context;
    this.cartModels = cartModels;
    for (CartModel model : cartModels) {
        total += model.getProductPrice();
    }
    // Set total textview

}