Question

我试图创建一种产品查看器。我已经获得了产品列表，但如果我点击该列表中的某个项目，我需要它来打开一个单独的产品视图。我已经尝试将产品的ID传递给新活动，但由于某种原因它无法正常工作。有人可以帮忙吗？提前谢谢。

这是我的产品清单：

public class inside_category extends Activity {

private static String _category;
List<product> Products = new ArrayList<product>();
ListView productListView;
private static List<product> productCategory = new ArrayList<product>();


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_inside_category);
    setTitle(_category);
    productListView = (ListView) findViewById(R.id.listView);
    addProduct();
    populateList();

    productListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
            product_view productviewer = new product_view();
            productviewer.setCurrentProductId(productCategory.get(position).getId());
            productviewer.setTitle(productCategory.get(position).getProductName());
            Intent intent = new Intent(inside_category.this, product_view.class);
            startActivity(intent);
        }
    });
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {

    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.inside_category, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

public static List<product> getProductCategory(){
    return productCategory;
}

public static void setCategory(String category){
    _category = category;
}

public void addProduct(){
    Products.add(new product("Socket AM3+",1, "i7", "Dayum", 430));
    Products.add(new product("Socket AM3+",2, "Cool", "yeah", 430));
    Products.add(new product("Socket 2011",3, "i5", "Not that dayum", 200));
    Products.add(new product("AMD",4, "i7", "Dayum", 430));
    Products.add(new product("Nvidia",5, "i5", "Not that dayum", 200));
    Products.add(new product("DDR2",6, "i7", "Dayum", 430));
    Products.add(new product("ATX",7, "i5", "Not that dayum", 200));

    int listLength = Products.size();
    for(int i = 0; i < listLength; i++){
        if(Products.get(i).getListId().contains(_category)){
            productCategory.add(Products.get(i));
        }
    }
}

private void populateList(){
    ArrayAdapter<product> adapter = new ProductListAdapter();
    productListView.setAdapter(adapter);
}


public String getCategory(){
    return _category;
}

private class ProductListAdapter extends ArrayAdapter<product>{
    public ProductListAdapter(){
        super (inside_category.this, R.layout.product, productCategory);
    }

    @Override
    public View getView(int position, View view, ViewGroup parent) {
        if (view == null)
            view = getLayoutInflater().inflate(R.layout.product, parent, false);

        product prod = productCategory.get(position);

        TextView name = (TextView) view.findViewById(R.id.productTitle);
        name.setText(prod.getProductName());
        TextView price = (TextView) view.findViewById(R.id.productPrice);
        price.setText("€"+prod.getProductPrice());

     return view;
    }
}
}

这是我试图将产品传递给我们的课程：

public class product_view extends Activity {
int currentProductId;
String Name, Description, ListId;
int Price;

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


@Override
public boolean onCreateOptionsMenu(Menu menu) {

    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.product_view, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

public void setCurrentProductId(int currentProductId){
    this.currentProductId = currentProductId;
}

public int getCurrentProductId(){
    return currentProductId;
}

private void populate(){
    for(int i = 0; i > prodCat.size(); i++ ){

        if(prodCat.get(i).getId() == currentProductId){
            Name = prodCat.get(i).getProductName();
            Price = prodCat.get(i).getProductPrice();
            Description = prodCat.get(i).getProductDescription();
            ListId = prodCat.get(i).getListId();
        }
    }

    product currentProduct = new product(ListId, currentProductId, Name, Description, Price);

    TextView name = (TextView) findViewById(R.id.productNameTitle);
    name.setText(currentproduct.getProductName());
    TextView price = (TextView) findViewById(R.id.productPriceView);
    price.setText("€"+currentproduct.getProductPrice());
    TextView productType = (TextView) findViewById(R.id.productTypeId);
    productType.setText(currentproduct.getListId());
    TextView description = (TextView) findViewById(R.id.productDescriptionView);
    description.setText(currentproduct.getProductDescription());
}
 }

Answer 1

ProductListAdapter需要覆盖getItemId方法：

@Override
public long getItemId(int position){
   // return the id(), or whatever you use to access the id on your product object
   return productCategory.get(position).id();
}

Answer 2

您无法像这样实例化product_view Activity。

 product_view view = new product_view();

然后调用它的方法，

您必须将产品ID或整个产品对象作为Intent extra传递给您的product_view类，如下所示，

Intent intent = new Intent(inside_category.this, product_view.class);
intent.putExtra("EXTRA_ID", productCategory.get(position).getId());
startActivity(intent);

然后在您的product_view活动中执行以下操作以获取ID。

String id = getIntent().getStringExtra("EXTRA_ID");

使用此ID，您可以获取产品并相应地填充product_view活动。

如果您无法仅使用ID获取数据，您还可以通过Intent传递整个产品对象。请参阅this for reference。

动态填充视图？

2 个答案: