Android 实现购物功能

实现购物功能需要考虑以下几个方面：

1. 商品展示：需要在应用中展示商品列表，可以使用 RecyclerView 或 ListView 等控件来展示商品信息，包括商品名称、价格、图片等。

2. 购物车：用户可以将商品添加到购物车中，可以使用 SQLite 数据库或 SharedPreferences 存储购物车中的商品信息。

3. 结算：用户可以对购物车中的商品进行结算，需要将购物车中的商品信息传递给结算页面，计算总价并提供支付功能。

4. 订单管理：用户可以查看历史订单和订单详情。

下面是一个简单的示例代码：

1. 商品展示

// 商品列表页面
public class ProductListActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    private ProductListAdapter adapter;
    private List<Product> productList;

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

        recyclerView = findViewById(R.id.recycler_view);
        productList = getProductList(); // 获取商品列表数据
        adapter = new ProductListAdapter(this, productList);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(adapter);
    }

    private List<Product> getProductList() {
        // 获取商品列表数据
    }
}

// 商品列表适配器
public class ProductListAdapter extends RecyclerView.Adapter<ProductListAdapter.ViewHolder> {
    private Context context;
    private List<Product> productList;

    public ProductListAdapter(Context context, List<Product> productList) {
        this.context = context;
        this.productList = productList;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).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.name.setText(product.getName());
        holder.price.setText(String.valueOf(product.getPrice()));
        // 加载商品图片
        Glide.with(context).load(product.getImageUrl()).into(holder.image);
    }

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

    static class ViewHolder extends RecyclerView.ViewHolder {
        TextView name;
        TextView price;
        ImageView image;

        ViewHolder(View itemView) {
            super(itemView);
            name = itemView.findViewById(R.id.name);
            price = itemView.findViewById(R.id.price);
            image = itemView.findViewById(R.id.image);
        }
    }
}

2. 购物车

// 商品详情页面
public class ProductDetailActivity extends AppCompatActivity {
    private Product product;

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

        product = getProduct(); // 获取商品详情数据
        // 显示商品详情信息
        TextView name = findViewById(R.id.name);
        name.setText(product.getName());
        TextView price = findViewById(R.id.price);
        price.setText(String.valueOf(product.getPrice()));
        ImageView image = findViewById(R.id.image);
        Glide.with(this).load(product.getImageUrl()).into(image);

        // 添加到购物车
        Button addToCartBtn = findViewById(R.id.add_to_cart_btn);
        addToCartBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addToCart(product);
            }
        });
    }

    private Product getProduct() {
        // 获取商品详情数据
    }

    private void addToCart(Product product) {
        List<Product> cartList = getCartList(); // 获取购物车列表
        boolean hasProduct = false;
        for (Product p : cartList) {
            if (p.getId() == product.getId()) {
                // 购物车中已存在该商品，数量加一
                p.setQuantity(p.getQuantity() + 1);
                hasProduct = true;
                break;
            }
        }
        if (!hasProduct) {
            // 购物车中不存在该商品，添加到购物车
            product.setQuantity(1);
            cartList.add(product);
        }
        saveCartList(cartList); // 保存购物车列表
        Toast.makeText(this, "已添加到购物车", Toast.LENGTH_SHORT).show();
    }

    private List<Product> getCartList() {
        // 从 SharedPreferences 或 SQLite 中获取购物车列表
    }

    private void saveCartList(List<Product> cartList) {
        // 将购物车列表保存到 SharedPreferences 或 SQLite 中
    }
}

3. 结算

// 购物车页面
public class ShoppingCartActivity extends AppCompatActivity {
    private List<Product> cartList;
    private ShoppingCartAdapter adapter;
    private TextView totalPriceText;

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

        cartList = getCartList(); // 获取购物车列表
        adapter = new ShoppingCartAdapter(this, cartList);
        RecyclerView recyclerView = findViewById(R.id.recycler_view);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(adapter);

        // 显示总价
        double totalPrice = getTotalPrice(cartList);
        totalPriceText = findViewById(R.id.total_price);
        totalPriceText.setText(String.valueOf(totalPrice));

        // 结算
        Button checkoutBtn = findViewById(R.id.checkout_btn);
        checkoutBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                checkout(cartList);
            }
        });
    }

    private List<Product> getCartList() {
        // 从 SharedPreferences 或 SQLite 中获取购物车列表
    }

    private double getTotalPrice(List<Product> cartList) {
        double totalPrice = 0;
        for (Product product : cartList) {
            totalPrice += product.getPrice() * product.getQuantity();
        }
        return totalPrice;
    }

    private void checkout(List<Product> cartList) {
        // 将购物车列表传递给结算页面
        Intent intent = new Intent(this, CheckoutActivity.class);
        intent.putExtra("cartList", (Serializable) cartList);
        startActivity(intent);
    }
}

// 购物车适配器
public class ShoppingCartAdapter extends RecyclerView.Adapter<ShoppingCartAdapter.ViewHolder> {
    private Context context;
    private List<Product> cartList;

    public ShoppingCartAdapter(Context context, List<Product> cartList) {
        this.context = context;
        this.cartList = cartList;
    }

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

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        Product product = cartList.get(position);
        holder.name.setText(product.getName());
        holder.price.setText(String.valueOf(product.getPrice()));
        holder.quantity.setText(String.valueOf(product.getQuantity()));
        // 加载商品图片
        Glide.with(context).load(product.getImageUrl()).into(holder.image);
    }

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

    static class ViewHolder extends RecyclerView.ViewHolder {
        TextView name;
        TextView price;
        TextView quantity;
        ImageView image;

        ViewHolder(View itemView) {
            super(itemView);
            name = itemView.findViewById(R.id.name);
            price = itemView.findViewById(R.id.price);
            quantity = itemView.findViewById(R.id.quantity);
            image = itemView.findViewById(R.id.image);
        }
    }
}

// 结算页面
public class CheckoutActivity extends AppCompatActivity {
    private List<Product> cartList;
    private TextView totalPriceText;

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

        cartList = (List<Product>) getIntent().getSerializableExtra("cartList"); // 获取购物车列表
        totalPriceText = findViewById(R.id.total_price);
        double totalPrice = getTotalPrice(cartList);
        totalPriceText.setText(String.valueOf(totalPrice));

        // 支付
        Button payBtn = findViewById(R.id.pay_btn);
        payBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                pay(totalPrice);
            }
        });
    }

    private double getTotalPrice(List<Product> cartList) {
        double totalPrice = 0;
        for (Product product : cartList) {
            totalPrice += product.getPrice() * product.getQuantity();
        }
        return totalPrice;
    }

    private void pay(double totalPrice) {
        // 调用支付接口
        Toast.makeText(this, "支付成功", Toast.LENGTH_SHORT).show();
        saveOrder(); // 保存订单信息
        finish();
    }

    private void saveOrder() {
        // 将购物车列表转换为订单信息，并保存到 SQLite 中
    }
}

4. 订单管理

// 历史订单页面
public class OrderHistoryActivity extends AppCompatActivity {
    private List<Order> orderList;
    private OrderListAdapter adapter;

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

        orderList = getOrderList(); // 获取历史订单列表
        adapter = new OrderListAdapter(this, orderList);
        RecyclerView recyclerView = findViewById(R.id.recycler_view);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(adapter);
    }

    private List<Order> getOrderList() {
        // 从 SQLite 中获取历史订单列表
    }
}

// 历史订单适配器
public class OrderListAdapter extends RecyclerView.Adapter<OrderListAdapter.ViewHolder> {
    private Context context;
    private List<Order> orderList;

    public OrderListAdapter(Context context, List<Order> orderList) {
        this.context = context;
        this.orderList = orderList;
    }

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

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        Order order = orderList.get(position);
        holder.orderId.setText(order.getOrderId());
        holder.orderTime.setText(order.getOrderTime());
        holder.totalPrice.setText(String.valueOf(order.getTotalPrice()));
        // 加载商品图片
        Glide.with(context).load(order.getProductList().get(0).getImageUrl()).into(holder.image);
    }

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

    static class ViewHolder extends RecyclerView.ViewHolder {
        TextView orderId;
        TextView orderTime;
        TextView totalPrice;
        ImageView image;

        ViewHolder(View itemView) {
            super(itemView);
            orderId = itemView.findViewById(R.id.order_id);
            orderTime = itemView.findViewById(R.id.order_time);
            totalPrice = itemView.findViewById(R.id.total_price);
            image = itemView.findViewById(R.id.image);
        }
    }
}

// 订单详情页面
public class OrderDetailActivity extends AppCompatActivity {
    private Order order;

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

        order = getOrder(); // 获取订单详情
        // 显示订单详情信息
        TextView orderId = findViewById(R.id.order_id);
        orderId.setText(order.getOrderId());
        TextView orderTime = findViewById(R.id.order_time);
        orderTime.setText(order.getOrderTime());
        TextView totalPrice = findViewById(R.id.total_price);
        totalPrice.setText(String.valueOf(order.getTotalPrice()));
        ImageView image = findViewById(R.id.image);
        Glide.with(this).load(order.getProductList().get(0).getImageUrl()).into(image);
    }

    private Order getOrder() {
        // 从 SQLite 中获取订单详情
    }
}

以上是一个简单的购物功能示例，具体实现方式可能有所不同，可以根据自己的需求进行调整。