带有CustomAdapter的Listview项目上的上下文菜单android不显示

Posted 2023-05-07

【中文标题】带有CustomAdapter的Listview项目上的上下文菜单android不显示

【英文标题】：Context menu android on Listview item with CustomAdapter doesn't show

【发布时间】：2016-04-14 19:51:18

【问题描述】：

我是 android 开发的新手，我试图在使用 CursorAdapter 的 Listview 上放置一个上下文菜单，我遵循了这个示例 https://www.youtube.com/watch?v=Pq9YQl0nfEk Using contextmenu with listview in android 但菜单没有出现，我也没有不为什么，看起来一切都很好。

这是我的活动代码

public class ProductsView extends AppCompatActivity 


    private FloatingActionButton botonAnadir;
    private ListView lvProducts;
    SetOfProductList mylist;
    private ProductAdapter productAdapter;
    Cursor cursor;
    private ProductList productList;
    private Long idProductList;
    private DBManager dbManager;


    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);

        Bundle bundle = getIntent().getExtras();
        if (bundle != null)
            productList = bundle.getParcelable("productList");
            setTitle(getResources().getString(R.string.show_products) + " " + productList.getName());
        
        setContentView(R.layout.products_view);
        initialize();
    
    private void initialize()
        botonAnadir = (FloatingActionButton)findViewById(R.id.button_add_product);
        lvProducts = (ListView)findViewById(R.id.listViewProducts);
        dbManager = new DBManager(getApplicationContext());
        loadProducts();
        registerForContextMenu(lvProducts);

        botonAnadir.setOnClickListener(new View.OnClickListener() 
            @Override
            public void onClick(View v) 
                creaNuevaLista();
            
        );

        lvProducts.setOnItemClickListener(new AdapterView.OnItemClickListener() 
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) 
                Product aux = getProduct(position);
                goToNewProduct(aux);
            
        );

        lvProducts.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() 
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) 
                // markAsPurchased(position);
                return true;

            
        );

    

    private void markAsPurchased(int position)
        Product p = getProduct(position);
        TextView item = (TextView) findViewById(R.id.textview_product_name);

        if (p.getPurchased() == 0)
            p.setPurchased(1);  //mark as a purchased
            item.setPaintFlags(item.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
        
        else
            p.setPurchased(0);  //mark as a purchased
            item.setPaintFlags(item.getPaintFlags() & (~Paint.STRIKE_THRU_TEXT_FLAG));
        
        editProduct(p); //makes de update
        loadProducts();
    

    private void editProduct(Product product)
        dbManager.updateProduct(product);
    

    private void goToNewProduct(Product p)
        Intent intent = new Intent(this,NewProductActivity.class);
        Bundle b = new Bundle();
        b.putBoolean("editMode",true);
        b.putParcelable("product", p);
        intent.putExtras(b);
        startActivity(intent);
    

    private void creaNuevaLista()
        Intent i = new Intent(this,NewProductActivity.class);
        Bundle b = new Bundle();
        b.putParcelable("productList", productList);
        i.putExtras(b);
        startActivityForResult(i, 0);

    

    private void loadProducts()
        cursor = dbManager.getAllProductsWithCursor(productList);
        productAdapter = new ProductAdapter(this,cursor);
        lvProducts.setAdapter(productAdapter);


    

    @Override
    public boolean onCreateOptionsMenu(Menu menu) 
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    

    @Override
    public boolean onOptionsItemSelected(MenuItem item) 
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) 
            return true;
        

        return super.onOptionsItemSelected(item);
    


    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) 
        super.onCreateContextMenu(menu, v, menuInfo);
        if (v.getId() == R.id.listViewProducts)
            MenuInflater inflater = getMenuInflater();
            inflater.inflate(R.menu.prodcut_view_context_menu,menu);
        

    

    @Override
    public boolean onContextItemSelected(MenuItem item) 
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
        switch (item.getItemId())
            case R.id.delete_id:
                return true;
            default:
                return super.onContextItemSelected(item);
        
    

这是我正在使用的适配器

 public class ProductAdapter extends CursorAdapter 
    private LayoutInflater inflater;


    //Constructor
    public ProductAdapter(Context context, Cursor cursor) 
        super(context, cursor,false);
    

    // The newView method is used to inflate a new view and return it,
    // you don't bind any data to the view at this point.
    @Override
    public View newView(Context context, Cursor cursor, ViewGroup parent) 
        inflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(R.layout.layout_product_row,parent,false);
        return view;
    

    // The bindView method is used to bind all data to a given view
    // such as setting the text on a TextView.
    @Override
    public void bindView(View view, Context context, Cursor cursor) 
        TextView tv_product_name = (TextView) view.findViewById(R.id.textview_product_name); // Find fields to populate in inflated template
        String product_name = cursor.getString(cursor.getColumnIndexOrThrow("name"));// Extract properties from cursor
        // Populate fields with extracted properties
        tv_product_name.setText(product_name);
        if (cursor.getInt(cursor.getColumnIndexOrThrow("purchased")) == 1)
            tv_product_name.setPaintFlags(tv_product_name.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
        
    

    public Product getProduct(int position, Cursor cursor) 
        Product p=null;
        if(cursor.moveToPosition(position)) 
            Log.e("PRODUCTLISTADAPTER","nombre es: "+cursor.getString(cursor.getColumnIndex("name")));
            p = new Product (cursor.getLong(cursor.getColumnIndex("_id")),cursor.getString(cursor.getColumnIndex("name")),
                    cursor.getString(cursor.getColumnIndex("unit_type")),cursor.getDouble(cursor.getColumnIndex("value")),cursor.getInt(cursor.getColumnIndex("purchased")),cursor.getLong(cursor.getColumnIndex("id_pl")));
        
        return p;
    

谁能解释我为什么它不起作用？没有必要在 LongClickListener 上做点什么吗？因为我没有看到正在创建菜单。

提前致谢。

【参考方案1】：

您为ListView 设置了OnItemLongClickListener，它将在上下文菜单创建之前运行。从其onItemLongClick() 方法中返回true 表示正在那里进行长按，因此不会创建菜单。

如果您实际上不需要OnItemLongClickListener，您可以删除相关代码。如果你也需要它，出于某种原因，你可以从onItemLongClick() 返回false，然后你的菜单就会显示出来。

【讨论】：

谢谢，我没注意到。