recyclerview无法显示图片~

Posted 2023-04-19

【中文标题】recyclerview无法显示图片~

【英文标题】：Unable to display images in recyclerview~

【发布时间】：2018-07-18 18:04:34

【问题描述】：

我知道这个问题已经被问过很多次，我查看了所有解决方案并尝试了它们，但我的应用程序仍然无法检索图像。

请帮忙！首先，没有显示图像，其次我的应用程序崩溃了。 我很确定我在这里缺少一些东西，但我无法弄清楚.. 在我的 firebase 数据库中，标题是“类别”“图像”“名称”。

    public class home extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener 

    FirebaseDatabase database;
    DatabaseReference category;
    TextView txtFullName;
    RecyclerView recycler_menu;
    RecyclerView.LayoutManager layoutManager;
    private FirebaseRecyclerAdapter<Category, MenuViewHolder> mFirebaseAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        toolbar.setTitle("Menu");
        setSupportActionBar(toolbar);

        //Get PassUserFullName from MainActivity main
        Intent i = getIntent();
        String PassUserFullName = i.getStringExtra("PassUserFullName");

        //init Firebase
        /*database = FirebaseDatabase.getInstance();
        category = database.getReference("Category");*/

       category=FirebaseDatabase.getInstance().getReference().child("Category");

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() 
            @Override
            public void onClick(View view) 
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            
        );

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        //Show Name of User
        View headerView = navigationView.getHeaderView(0);
/*        txtFullName = (TextView)headerView.findViewById(R.id.txtFullName);

        txtFullName.setText(""+PassUserFullName);
        *//*if 
            Toast.makeText(home.this, "User data field is null",
                    Toast.LENGTH_SHORT).show();
        
        */

        //Load Menu
        recycler_menu=(RecyclerView)findViewById(R.id.recycler_menu);
        recycler_menu.setHasFixedSize(true);
        layoutManager=new LinearLayoutManager(this);
        recycler_menu.setLayoutManager(layoutManager);
        loadMenu();
    
    private void loadMenu()
        FirebaseRecyclerAdapter<Category,MenuViewHolder> adapter = new FirebaseRecyclerAdapter<Category, MenuViewHolder>(Category.class,R.layout.menu_item,MenuViewHolder.class,category) 
            @Override
            protected void populateViewHolder(MenuViewHolder viewHolder, Category model, int position) 
                viewHolder.txtMenuName.setText(model.getName());
                Picasso.with(getBaseContext()).load(model.getImage()).into(viewHolder.imageView);
                final Category clickItem = model;
                viewHolder.setItemClickListener(new ItemClickListener() 
                    @Override
                    public void onClick(View view, int position, boolean isLongClick) 
                        Toast.makeText(home.this,""+clickItem.getName(),Toast.LENGTH_SHORT).show();
                    
                );
            
        ;
        recycler_menu.setAdapter(adapter);
    


    @Override
    public void onBackPressed() 
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) 
            drawer.closeDrawer(GravityCompat.START);
         else 
            super.onBackPressed();
        
    

    @Override
    public boolean onCreateOptionsMenu(Menu menu) 
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.home, menu);
        return true;
    

    @Override
    public boolean onOptionsItemSelected(MenuItem item) 

        return super.onOptionsItemSelected(item);
    

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) 
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_menu) 
            // Handle the camera action
         else if (id == R.id.nav_cart) 

         else if (id == R.id.nav_orders) 

         else if (id == R.id.nav_log_out) 

        

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    





public class Category 
    public String Image;
    public String Name;

    public Category()
    
    public Category(String Image, String Name)
        this.Image = Image;
        this.Name = Name;
    
    public String getImage() 
        return Image;
    
    public String getName() 
        return Name;
    

    public void setImage(String Image) 
        this.Image = Image;
    
    public void setName(String Name) 
        this.Name = Name;
    

【问题讨论】：

添加您的适配器代码

...也请添加日志

【参考方案1】：

当您使用RecyclerView 时，您并没有将list 数据传递给您的适配器，只有您使用了setAdapter。将列表数据传递给您的 RecyclerAdapter 类，并通过适配器类中的 cosntructor 获取。

private void loadMenu()
        FirebaseRecyclerAdapter<Category,MenuViewHolder> adapter = new FirebaseRecyclerAdapter<Category, MenuViewHolder>(Category.class,R.layout.menu_item,MenuViewHolder.class,category) 
            @Override
            protected void populateViewHolder(MenuViewHolder viewHolder, Category model, int position) 
                viewHolder.txtMenuName.setText(model.getName());
                Picasso.with(getBaseContext()).load(model.getImage()).into(viewHolder.imageView);
                final Category clickItem = model;
                viewHolder.setItemClickListener(new ItemClickListener() 
                    @Override
                    public void onClick(View view, int position, boolean isLongClick) 
                        Toast.makeText(home.this,""+clickItem.getName(),Toast.LENGTH_SHORT).show();
                    
                );
            
        ;
        mFirebaseAdapter= new FirebaseRecyclerAdapter(home.this, yourList);
        recycler_menu.setAdapter(adapter);
    

有关 RecyclerView 的更多信息，请查看：https://antonioleiva.com/recyclerview/