跟据上述电商app案例给出完整代码

以下是一个简单的电商App的完整代码示例。这个App展示了一个产品列表，当用户点击其中一个产品时，会跳转到该产品的详细信息页面。

MainActivity.java

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import androidx.appcompat.app.AppCompatActivity;
import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    private ArrayList<Product> products = new ArrayList<>();

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

        // 初始化产品列表
        initProducts();

        // 设置产品列表的适配器
        ProductAdapter adapter = new ProductAdapter(this, products);
        ListView listView = findViewById(R.id.list_view);
        listView.setAdapter(adapter);

        // 设置产品列表的点击事件
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
                // 跳转到产品详情页
                Intent intent = new Intent(MainActivity.this, ProductDetailActivity.class);
                intent.putExtra("product", products.get(position));
                startActivity(intent);
            }
        });
    }

    // 初始化产品列表
    private void initProducts() {
        products.add(new Product("商品1", "这是商品1的描述", 50));
        products.add(new Product("商品2", "这是商品2的描述", 100));
        products.add(new Product("商品3", "这是商品3的描述", 150));
        products.add(new Product("商品4", "这是商品4的描述", 200));
        products.add(new Product("商品5", "这是商品5的描述", 250));
        products.add(new Product("商品6", "这是商品6的描述", 300));
    }
}

ProductAdapter.java

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import java.util.ArrayList;

public class ProductAdapter extends BaseAdapter {

    private Context context;
    private ArrayList<Product> products;

    public ProductAdapter(Context context, ArrayList<Product> products) {
        this.context = context;
        this.products = products;
    }

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

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = LayoutInflater.from(context).inflate(R.layout.list_item, parent, false);
        }

        TextView nameTextView = convertView.findViewById(R.id.name_text_view);
        TextView priceTextView = convertView.findViewById(R.id.price_text_view);

        Product product = products.get(position);
        nameTextView.setText(product.getName());
        priceTextView.setText(String.valueOf(product.getPrice()));

        return convertView;
    }
}

ProductDetailActivity.java

import android.os.Bundle;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;

public class ProductDetailActivity extends AppCompatActivity {

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

        // 获取传递过来的产品对象
        Product product = (Product) getIntent().getSerializableExtra("product");

        // 显示产品的详细信息
        ImageView imageView = findViewById(R.id.image_view);
        TextView nameTextView = findViewById(R.id.name_text_view);
        TextView descriptionTextView = findViewById(R.id.description_text_view);
        TextView priceTextView = findViewById(R.id.price_text_view);

        imageView.setImageResource(R.drawable.product_image);
        nameTextView.setText(product.getName());
        descriptionTextView.setText(product.getDescription());
        priceTextView.setText(String.valueOf(product.getPrice()));
    }
}

activity_main.xml

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

    <ListView
            android:id="@+id/list_view"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

</LinearLayout>

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="horizontal"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:padding="16dp">

    <TextView
            android:id="@+id/name_text_view"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:textSize="18sp"
            android:textStyle="bold"/>

    <TextView
            android:id="@+id/price_text_view"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="18sp"
            android:textStyle="bold"/>

</LinearLayout>

activity_product_detail.xml

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

    <LinearLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="16dp">

        <ImageView
                android:id="@+id/image_view"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:scaleType="centerCrop"/>

        <TextView
                android:id="@+id/name_text_view"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textSize="24sp"
                android:textStyle="bold"
                android:paddingTop="16dp"
                android:paddingBottom="16dp"/>

        <TextView
                android:id="@+id/description_text_view"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textSize="18sp"
                android:paddingBottom="16dp"/>

        <TextView
                android:id="@+id/price_text_view"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textSize="24sp"
                android:textStyle="bold"
                android:paddingBottom="16dp"/>

    </LinearLayout>

</ScrollView>

Product.java

import java.io.Serializable;

public class Product implements Serializable {

    private String name;
    private String description;
    private int price;

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

    public String getName() {
        return name;
    }

    public String getDescription() {
        return description;
    }

    public int getPrice() {
        return price;
    }
}