商品界面的UI和java

以下是一个简单的商品列表展示界面的UI和Java代码：

1. 商品列表展示界面的UI

<?xml version="1.0" encoding="utf-8"?>
<androidx.recyclerview.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/white" />

2. 商品列表展示界面的Java代码

public class ProductListActivity extends AppCompatActivity {

    private RecyclerView mRecyclerView;
    private ProductListAdapter mAdapter;

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

        mRecyclerView = findViewById(R.id.recycler_view);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));

        List<Product> productList = getProductList(); // 获取商品列表数据
        mAdapter = new ProductListAdapter(productList);
        mRecyclerView.setAdapter(mAdapter);
    }

    private List<Product> getProductList() {
        // 从数据库中获取商品列表数据
        // TODO: 实现从数据库获取商品列表数据的逻辑
        return new ArrayList<>();
    }

    private class ProductListAdapter extends RecyclerView.Adapter<ProductViewHolder> {

        private List<Product> mProductList;

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

        @NonNull
        @Override
        public ProductViewHolder onCreateViewHolder(@NonNull 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(@NonNull ProductViewHolder holder, int position) {
            Product product = mProductList.get(position);
            holder.mNameTextView.setText(product.getName());
            holder.mPriceTextView.setText(String.valueOf(product.getPrice()));
            holder.mQuantityTextView.setText(String.valueOf(product.getQuantity()));
        }

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

    private static class ProductViewHolder extends RecyclerView.ViewHolder {

        private TextView mNameTextView;
        private TextView mPriceTextView;
        private TextView mQuantityTextView;

        public ProductViewHolder(@NonNull View itemView) {
            super(itemView);
            mNameTextView = itemView.findViewById(R.id.tv_name);
            mPriceTextView = itemView.findViewById(R.id.tv_price);
            mQuantityTextView = itemView.findViewById(R.id.tv_quantity);
        }
    }
}

其中，`Product`是一个商品类，包含商品的名称、价格和数量等信息。`item_product.xml`是商品列表项的布局文件，包含商品名称、价格和数量等控件。在`ProductListAdapter`中，我们将商品列表项展示在了RecyclerView中，并根据需要实现了自定义的ViewHolder。