android studio实现简单购物车项目完整代码

以下是一个简单的购物车项目的完整代码，包含了商品列表、购物车功能和结算功能。

MainActivity.java

package com.example.shoppingcart;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    private ListView listView;
    private TextView totalTextView;
    private Button checkoutButton;

    private ArrayList<Product> productList;
    private ArrayAdapter<Product> productAdapter;

    private ArrayList<Product> cartList;
    private ArrayAdapter<Product> cartAdapter;

    private double total = 0.0;

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

        listView = findViewById(R.id.listView);
        totalTextView = findViewById(R.id.totalTextView);
        checkoutButton = findViewById(R.id.checkoutButton);

        productList = new ArrayList<Product>();
        productList.add(new Product("Product 1", 10.0));
        productList.add(new Product("Product 2", 20.0));
        productList.add(new Product("Product 3", 30.0));
        productList.add(new Product("Product 4", 40.0));
        productList.add(new Product("Product 5", 50.0));

        productAdapter = new ArrayAdapter<Product>(this, android.R.layout.simple_list_item_1, productList);
        listView.setAdapter(productAdapter);

        cartList = new ArrayList<Product>();
        cartAdapter = new ArrayAdapter<Product>(this, android.R.layout.simple_list_item_1, cartList);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Product product = productAdapter.getItem(i);
                cartList.add(product);
                cartAdapter.notifyDataSetChanged();
                total += product.getPrice();
                totalTextView.setText("Total: $" + total);
            }
        });

        checkoutButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (cartList.isEmpty()) {
                    Toast.makeText(MainActivity.this, "Your cart is empty", Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(MainActivity.this, "Thank you for your purchase!", Toast.LENGTH_SHORT).show();
                    cartList.clear();
                    cartAdapter.notifyDataSetChanged();
                    total = 0.0;
                    totalTextView.setText("Total: $" + total);
                }
            }
        });
    }
}

Product.java

package com.example.shoppingcart;

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

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

    public String getName() {
        return name;
    }

    public double getPrice() {
        return price;
    }

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

activity_main.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">

    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/totalTextView"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Total: $0.0"
            android:textSize="18sp" />

        <Button
            android:id="@+id/checkoutButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Checkout"
            android:textSize="18sp" />

    </LinearLayout>

    <ListView
        android:id="@+id/cartListView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

</LinearLayout>

这个购物车项目使用了两个ListView，一个显示商品列表，一个显示购物车列表。当用户点击商品列表中的某个商品时，该商品将会被添加到购物车中，并更新购物车列表和总价。当用户点击结算按钮时，如果购物车为空，将会弹出提示信息；否则，会弹出感谢购买的提示信息，并清空购物车列表和总价。