我正在开发一个Android应用程序，其中用户选择一个特定的食物类别（即itemlist.java）。如果用户选择鸡，则将显示相应的项目列表。然后，当用户点击并点击另一个类别（即素食快乐）时，它仍然显示与鸡肉相同的列表。位置变量已更改，但不会上载目录资源。 请帮我解决这个问题。
Shoppincarthelper.java
public class ShoppingCartHelper {
public static final String PRODUCT_INDEX = "PRODUCT_INDEX";
private static List<Product1> itemlist;
private static List<Product> catalog;
private static List<Product> cart;
public static final String PRODUCT_INDEX = "PRODUCT_INDEX";
public static List<Product> getCatalog(Resources res) {
if(catalog == null) {
catalog = new Vector<Product>();
catalog.add(new Product("Chicken Kadai", res.getDrawable(R.drawable.new_kadai),"Kadai Chicken is a spicy chicken dish that is a little dry in nature with a rich aroma given by the Ginger and curry leaves",123, 0));
}
return catalog;
}
public static List<Product1> getCatalog1(Resources res) {
if(itemlist == null) {
itemlist = new Vector<Product1>();
itemlist.add(new Product1("Chicken "));
itemlist.add(new Product1("Vegetarian Delight"));
itemlist.add(new Product1("Rice"));
itemlist.add(new Product1("Drinks"));
}
return itemlist;
}
public static List<Product> getCatalog2(Resources res) {
if(catalog == null) {
catalog = new Vector<Product>();
catalog.add(new Product("Chana Masala", res
.getDrawable(R.drawable.chanamasala),
" Chana masala or chole masala is a popular vegetable dish in Pakistani cuisine & Indian cuisine.The main ingredient is chickpeas.It is fairly dry and spicy with a sour citrus note. ",80));
}
return catalog;
}
public static List<Product> getCatalog3(Resources res) {
if(catalog == null) {
catalog = new Vector<Product>();
catalog.add(new Product("Jeera Rice ", res
.getDrawable(R.drawable.jeerarice),
"Jeera Rice (Cumin flavored rice), is a simple and tasty variation on plain boiled rice made with cumin seeds. ",80));
catalog.add(new Product("Filipino Fried Rice ", res
.getDrawable(R.drawable.friedrice),
"Philippine style fried rice is a simple dish of rice, meat/and or vegetables, a little oil, some spice and a garnish. ",95));
catalog.add(new Product("VEG Biryani ", res
.getDrawable(R.drawable.vegbiryani),
"Vegetable Biryani, is a rich Indian Moghlai pullao layered with curry. Kabuli Chana Biryani, Hyderabadi Biryani and lots more ",60));
}
Itemlist.java
public class ItemList extends Activity {
private List<Product1> mProductList1;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.itemlist);
// Obtain a reference to the product catalog
mProductList1 = ShoppingCartHelper.getCatalog1(getResources());
// Create the list
ListView listViewCatalog = (ListView) findViewById(R.id.listView1);
listViewCatalog.setAdapter(new ProductAdapter1(mProductList1, getLayoutInflater()));
listViewCatalog.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,long id) {
Intent CatalogIntent = new Intent(getBaseContext(),CatalogActivity.class);
CatalogIntent.putExtra(ShoppingCartHelper.PRODUCT_INDEX,position);
startActivity(CatalogIntent);
}
});
}
}
CatalogActvity.java
public class CatalogActivity extends Activity {
private List<Product> mProductList;
/** Called when the activity is first created.
* @param CatalogIntent
* @param position */
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.catalog);
int ListIndex =getIntent().getExtras().getInt(ShoppingCartHelper.PRODUCT_INDEX);
mProductList = ShoppingCartHelper.getCatalog(getResources());
if(ListIndex==1)
{
mProductList = ShoppingCartHelper.getCatalog2(getResources());
}
if(ListIndex==2)
{
mProductList = ShoppingCartHelper.getCatalog3(getResources());
}
// Create the list
ListView listViewCatalog = (ListView) findViewById(R.id.ListViewCatalog);
listViewCatalog.setAdapter(new ProductAdapter(mProductList, getLayoutInflater(), false));
listViewCatalog.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,long id) {
Intent productDetailsIntent = new Intent(getBaseContext(),ProductDetailsActivity.class);
productDetailsIntent.putExtra(ShoppingCartHelper.PRODUCT_INDEX, position);
startActivity(productDetailsIntent);
}
});
Button viewShoppingCart = (Button) findViewById(R.id.ButtonViewCart);
viewShoppingCart.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent viewShoppingCartIntent = new Intent(getBaseContext(), ShoppingCartActivity.class);
startActivity(viewShoppingCartIntent);
}
});
}
public void onBackPressed() {
Intent ListIntent = new Intent(getBaseContext(),ItemList.class);
startActivity(ListIntent);
}
}
ProductAdapter1.java
public class ProductAdapter1 extends BaseAdapter {
private List<Product1> mProductList1;
private LayoutInflater mInflater;
public ProductAdapter1(List<Product1> list, LayoutInflater inflater) {
mProductList1 = list;
mInflater = inflater;
}
@Override
public int getCount() {
return mProductList1.size();
}
@Override
public Object getItem(int position) {
return mProductList1.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
final ViewItem item;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.itemlistcon,null);
item = new ViewItem();
item.productTitle = (TextView) convertView.findViewById(R.id.textView1);
convertView.setTag(item);
} else {
item = (ViewItem) convertView.getTag();
}
Product1 curProduct = mProductList1.get(position);
item.productTitle.setText(curProduct.title);
return convertView;
}
public class ViewItem
{
TextView productTitle;
}
}