android 购物车实现,Android Studio实现简单购物车功能

好的，我可以给你一些实现购物车功能的思路和步骤：

1. 创建一个商品类，包含商品的名称、价格、数量等属性；
2. 创建一个购物车类，包含商品列表、添加商品、删除商品、计算总价等方法；
3. 在界面上显示商品列表，并提供添加到购物车的按钮；
4. 当添加到购物车时，将商品对象添加到购物车中，并更新购物车的显示；
5. 在购物车界面上显示购物车中的商品列表、数量、价格等信息；
6. 可以提供删除商品、修改数量、清空购物车等操作；
7. 计算购物车中的总价，并显示在界面上。

这些步骤可以通过以下代码实现：

1. 商品类

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 double getPrice() {
        return price;
    }

    public int getQuantity() {
        return quantity;
    }

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

2. 购物车类

public class ShoppingCart {
    private List<Product> productList = new ArrayList<>();

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

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

    public double getTotalPrice() {
        double totalPrice = 0;
        for (Product product : productList) {
            totalPrice += product.getPrice() * product.getQuantity();
        }
        return totalPrice;
    }

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

3. 商品列表界面

public class ProductListActivity extends AppCompatActivity {
    private List<Product> productList = new ArrayList<>();
    private RecyclerView recyclerView;
    private ProductListAdapter adapter;

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

        // 初始化商品列表
        productList.add(new Product("商品1", 10.0, 100));
        productList.add(new Product("商品2", 20.0, 200));
        productList.add(new Product("商品3", 30.0, 300));

        // 初始化RecyclerView
        recyclerView = findViewById(R.id.recyclerView);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        adapter = new ProductListAdapter(productList);
        recyclerView.setAdapter(adapter);
    }

    private class ProductListAdapter extends RecyclerView.Adapter<ProductViewHolder> {
        private List<Product> productList;

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

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

        @Override
        public void onBindViewHolder(ProductViewHolder holder, int position) {
            final 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.addButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    // 添加到购物车
                    ShoppingCart.getInstance().addProduct(product);
                    Toast.makeText(ProductListActivity.this, "添加成功", Toast.LENGTH_SHORT).show();
                }
            });
        }

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

    private static class ProductViewHolder extends RecyclerView.ViewHolder {
        TextView nameTextView;
        TextView priceTextView;
        TextView quantityTextView;
        Button addButton;

        public ProductViewHolder(View itemView) {
            super(itemView);

            nameTextView = itemView.findViewById(R.id.nameTextView);
            priceTextView = itemView.findViewById(R.id.priceTextView);
            quantityTextView = itemView.findViewById(R.id.quantityTextView);
            addButton = itemView.findViewById(R.id.addButton);
        }
    }
}

4. 购物车界面

public class ShoppingCartActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    private ShoppingCartAdapter adapter;

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

        // 初始化RecyclerView
        recyclerView = findViewById(R.id.recyclerView);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        adapter = new ShoppingCartAdapter(ShoppingCart.getInstance().getProductList());
        recyclerView.setAdapter(adapter);

        // 显示总价
        TextView totalPriceTextView = findViewById(R.id.totalPriceTextView);
        double totalPrice = ShoppingCart.getInstance().getTotalPrice();
        totalPriceTextView.setText(String.format("总价：%.2f元", totalPrice));

        // 清空购物车
        Button clearButton = findViewById(R.id.clearButton);
        clearButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ShoppingCart.getInstance().clear();
                adapter.notifyDataSetChanged();
                TextView totalPriceTextView = findViewById(R.id.totalPriceTextView);
                totalPriceTextView.setText("总价：0.00元");
            }
        });
    }

    private class ShoppingCartAdapter extends RecyclerView.Adapter<ProductViewHolder> {
        private List<Product> productList;

        public ShoppingCartAdapter(List<Product> productList) {
            this.productList = productList;
        }

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

        @Override
        public void onBindViewHolder(ProductViewHolder holder, int position) {
            final 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.deleteButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    // 从购物车中删除
                    ShoppingCart.getInstance().removeProduct(product);
                    adapter.notifyDataSetChanged();

                    // 更新总价
                    TextView totalPriceTextView = findViewById(R.id.totalPriceTextView);
                    double totalPrice = ShoppingCart.getInstance().getTotalPrice();
                    totalPriceTextView.setText(String.format("总价：%.2f元", totalPrice));
                }
            });

            holder.quantityEditText.setText(String.valueOf(product.getQuantity()));
            holder.quantityEditText.addTextChangedListener(new TextWatcher() {
                @Override
                public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                }

                @Override
                public void onTextChanged(CharSequence s, int start, int before, int count) {
                    if (TextUtils.isEmpty(s)) {
                        return;
                    }

                    int quantity = Integer.parseInt(s.toString());
                    product.setQuantity(quantity);

                    // 更新总价
                    TextView totalPriceTextView = findViewById(R.id.totalPriceTextView);
                    double totalPrice = ShoppingCart.getInstance().getTotalPrice();
                    totalPriceTextView.setText(String.format("总价：%.2f元", totalPrice));
                }

                @Override
                public void afterTextChanged(Editable s) {
                }
            });
        }

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

以上就是一个简单的购物车功能的实现，你可以根据自己的需求来进行扩展和优化。