Android中设计一个购物车页面可实现商品数量的增减、商品的删除以及总价格计算功能。给出代码，页面布局用线性布局

好的，请参考下面的代码实现：

布局文件 cart_layout.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <!--商品列表-->
    <ListView
        android:id="@+id/lv_cart"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

    <!--底部总价和结算按钮-->
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:padding="16dp">

        <!--总价-->
        <TextView
            android:id="@+id/tv_total_price"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:textSize="16sp"
            android:text="总价：0元" />

        <!--结算按钮-->
        <Button
            android:id="@+id/btn_checkout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="结算" />
    </LinearLayout>
</LinearLayout>

Java代码 CartActivity.java：

public class CartActivity extends AppCompatActivity {

    private ListView listView;
    private CartAdapter adapter;
    private List<CartItem> cartItems;
    private TextView tvTotalPrice;
    private Button btnCheckout;

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

        listView = findViewById(R.id.lv_cart);
        tvTotalPrice = findViewById(R.id.tv_total_price);
        btnCheckout = findViewById(R.id.btn_checkout);

        // 初始化购物车数据
        cartItems = new ArrayList<>();
        cartItems.add(new CartItem("商品1", 10, 1));
        cartItems.add(new CartItem("商品2", 20, 2));
        cartItems.add(new CartItem("商品3", 30, 3));
        cartItems.add(new CartItem("商品4", 40, 4));
        cartItems.add(new CartItem("商品5", 50, 5));

        // 设置适配器
        adapter = new CartAdapter(this, cartItems);
        listView.setAdapter(adapter);

        // 设置总价
        tvTotalPrice.setText("总价：" + getTotalPrice() + "元");

        // 设置结算按钮的点击事件
        btnCheckout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 结算
                Toast.makeText(CartActivity.this, "结算", Toast.LENGTH_SHORT).show();
            }
        });
    }

    // 获取总价
    private int getTotalPrice() {
        int totalPrice = 0;
        for (CartItem item : cartItems) {
            totalPrice += item.getPrice() * item.getCount();
        }
        return totalPrice;
    }

    // 购物车适配器
    private class CartAdapter extends BaseAdapter {

        private Context context;
        private List<CartItem> cartItems;

        public CartAdapter(Context context, List<CartItem> cartItems) {
            this.context = context;
            this.cartItems = cartItems;
        }

        @Override
        public int getCount() {
            return cartItems.size();
        }

        @Override
        public Object getItem(int position) {
            return cartItems.get(position);
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {
            ViewHolder holder;
            if (convertView == null) {
                convertView = LayoutInflater.from(context).inflate(R.layout.cart_item_layout, null);
                holder = new ViewHolder();
                holder.tvName = convertView.findViewById(R.id.tv_name);
                holder.tvPrice = convertView.findViewById(R.id.tv_price);
                holder.tvCount = convertView.findViewById(R.id.tv_count);
                holder.btnIncrease = convertView.findViewById(R.id.btn_increase);
                holder.btnDecrease = convertView.findViewById(R.id.btn_decrease);
                holder.btnDelete = convertView.findViewById(R.id.btn_delete);
                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }

            // 设置数据
            final CartItem item = cartItems.get(position);
            holder.tvName.setText(item.getName());
            holder.tvPrice.setText("单价：" + item.getPrice() + "元");
            holder.tvCount.setText(String.valueOf(item.getCount()));

            // 增加商品数量
            holder.btnIncrease.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    item.setCount(item.getCount() + 1);
                    notifyDataSetChanged();
                    tvTotalPrice.setText("总价：" + getTotalPrice() + "元");
                }
            });

            // 减少商品数量
            holder.btnDecrease.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (item.getCount() > 1) {
                        item.setCount(item.getCount() - 1);
                        notifyDataSetChanged();
                        tvTotalPrice.setText("总价：" + getTotalPrice() + "元");
                    }
                }
            });

            // 删除商品
            holder.btnDelete.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    cartItems.remove(position);
                    notifyDataSetChanged();
                    tvTotalPrice.setText("总价：" + getTotalPrice() + "元");
                }
            });

            return convertView;
        }

        private class ViewHolder {
            TextView tvName;
            TextView tvPrice;
            TextView tvCount;
            Button btnIncrease;
            Button btnDecrease;
            Button btnDelete;
        }
    }

    // 商品类
    private class CartItem {
        private String name;    // 商品名称
        private int price;      // 商品单价
        private int count;      // 商品数量

        public CartItem(String name, int price, int count) {
            this.name = name;
            this.price = price;
            this.count = count;
        }

        public String getName() {
            return name;
        }

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

        public int getPrice() {
            return price;
        }

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

        public int getCount() {
            return count;
        }

        public void setCount(int count) {
            this.count = count;
        }
    }
}

注：上述代码仅供参考，可能有一些细节需要根据实际情况进行调整。