用Android实现一个购物车，以列表的形式显示商品信息，，并可以对商品进行加入购物车、删除、修改数量和查询

商品价格等操作。

首先，我们需要创建一个商品类，包含商品名称、价格和数量等属性：

public class Product {
    private String name;
    private double price;
    private int quantity;

    public Product(String name, double price, int quantity) {
        this.name = name;
        this.price = price;
        this.quantity = quantity;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public int getQuantity() {
        return quantity;
    }

    public void setQuantity(int quantity) {
        this.quantity = quantity;
    }

    @Override
    public String toString() {
        return name + " - " + price + " - " + quantity;
    }
}

接下来，我们创建一个购物车类，用于管理商品列表：

public class ShoppingCart {
    private List<Product> productList;

    public ShoppingCart() {
        productList = new ArrayList<>();
    }

    public void addProduct(Product product) {
        productList.add(product);
    }

    public void removeProduct(Product product) {
        productList.remove(product);
    }

    public void updateProductQuantity(Product product, int quantity) {
        product.setQuantity(quantity);
    }

    public List<Product> getProductList() {
        return productList;
    }
}

接下来，我们需要创建一个布局文件，用于显示商品列表。在布局文件中，我们可以使用RecyclerView来显示商品列表，并为每个商品添加一个加入购物车按钮：

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/product_list"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

<Button
    android:id="@+id/add_to_cart_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Add to Cart"/>

接下来，我们需要创建一个适配器类，用于将商品列表显示在RecyclerView中：

public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ViewHolder> {
    private List<Product> productList;
    private OnAddToCartClickListener listener;

    public ProductAdapter(List<Product> productList, OnAddToCartClickListener listener) {
        this.productList = productList;
        this.listener = listener;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_product, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        Product product = productList.get(position);
        holder.nameTextView.setText(product.getName());
        holder.priceTextView.setText(String.valueOf(product.getPrice()));
        holder.quantityTextView.setText(String.valueOf(product.getQuantity()));
        holder.addToCartButton.setOnClickListener(view -> listener.onAddToCartClick(product));
    }

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

    public static class ViewHolder extends RecyclerView.ViewHolder {
        private TextView nameTextView;
        private TextView priceTextView;
        private TextView quantityTextView;
        private Button addToCartButton;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            nameTextView = itemView.findViewById(R.id.product_name);
            priceTextView = itemView.findViewById(R.id.product_price);
            quantityTextView = itemView.findViewById(R.id.product_quantity);
            addToCartButton = itemView.findViewById(R.id.add_to_cart_button);
        }
    }

    public interface OnAddToCartClickListener {
        void onAddToCartClick(Product product);
    }
}

最后，我们需要在MainActivity中使用上述类来实现购物车的基本功能：

public class MainActivity extends AppCompatActivity implements ProductAdapter.OnAddToCartClickListener {
    private ShoppingCart shoppingCart;
    private ProductAdapter productAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        shoppingCart = new ShoppingCart();

        RecyclerView productList = findViewById(R.id.product_list);
        productAdapter = new ProductAdapter(getProductList(), this);
        productList.setAdapter(productAdapter);
        productList.setLayoutManager(new LinearLayoutManager(this));
    }

    private List<Product> getProductList() {
        List<Product> productList = new ArrayList<>();
        productList.add(new Product("Product 1", 10.0, 5));
        productList.add(new Product("Product 2", 20.0, 3));
        productList.add(new Product("Product 3", 30.0, 2));
        return productList;
    }

    @Override
    public void onAddToCartClick(Product product) {
        shoppingCart.addProduct(product);
        productAdapter.notifyDataSetChanged();
    }
}

在MainActivity中，我们创建了一个ShoppingCart对象，并将商品列表显示在RecyclerView中。当用户点击加入购物车按钮时，我们将商品添加到购物车中，并更新RecyclerView中的商品列表。