Question

当evr单击foodmenu时，它显示黑屏，我的代码已正确编写在firebase recyclerview适配器中

图片1：

图2将显示错误黑屏：

在此foodList.java类中必须进行哪些更改，我尝试使用firebase recycler选项适配器，并将firebase数据库的权限设置为true。它附加了no适配器。 FoodList.java

public class FoodList extends AppCompatActivity {

    RecyclerView recycler_food;
    RecyclerView.LayoutManager layoutManager;

    FirebaseDatabase database;
    DatabaseReference foodList;

    String categoryId = "";
    FirebaseRecyclerAdapter<Food, FoodViewHolder> adapter;

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

        database = FirebaseDatabase.getInstance();
        foodList = database.getReference("Foods");

        recycler_food = (RecyclerView) findViewById(R.id.recyclerfood);
        recycler_food.setHasFixedSize(true);
        layoutManager = new LinearLayoutManager(this);
        recycler_food.setLayoutManager(layoutManager);

        if (getIntent() != null)
            categoryId = getIntent().getStringExtra("CategoryId");
        if (categoryId != null && categoryId.isEmpty()) {
            loadListFood(categoryId);
        }
    }

    private void loadListFood(String categoryId) {

        Query food = null;
        assert food != null;
        FirebaseRecyclerOptions<Food> options =
                new FirebaseRecyclerOptions.Builder<Food>()
                        .setQuery(food, Food.class).build();

        adapter = new FirebaseRecyclerAdapter<Food, FoodViewHolder>(options) {
            @Override
            public FoodViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {


                View view = LayoutInflater.from(parent.getContext())
                        .inflate(R.layout.food_item, parent, false);

                return new FoodViewHolder(view);
            }

            @Override
            protected void onBindViewHolder(@NonNull FoodViewHolder holder, int position, @NonNull Food model) {
                holder.food_name.setText(model.getName());
                Picasso.with(getBaseContext()).load(model.getImage()).into(holder.food_image);
                final Food local = model;
                holder.setItemClickListener(new ItemClickListener() {
                    @Override
                    public void onClick(View view, int position, boolean isLongClick) {
                        Toast.makeText(FoodList.this, "" + local.getName(), Toast.LENGTH_SHORT).show();
                    }
                });
            }
        };
        recycler_food.setAdapter(adapter);
        adapter.startListening();
    }
}

FoodViewHolder

public class FoodViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    public TextView food_name;
    public ImageView food_image;

    private ItemClickListener itemClickListener;

    public void setItemClickListener(ItemClickListener itemClickListener) {
        this.itemClickListener = itemClickListener;
    }

    public FoodViewHolder(View itemView) {
        super(itemView);

        food_name = itemView.findViewById(R.id.food_name);
        food_image = itemView.findViewById(R.id.food_image);
        itemView.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        itemClickListener.onClick(view,getAdapterPosition(),false);
    }

}

Logcat错误显示

   06-26 20:57:44.626 15914-15914/com.example.sharma.digimenu I/Timeline: Timeline: Activity_launch_request id:com.example.sharma.digimenu time:94010711
06-26 20:57:44.637 15914-15942/com.example.sharma.digimenu V/FA: Recording user engagement, ms: 2649
06-26 20:57:44.638 15914-15942/com.example.sharma.digimenu V/FA: Activity paused, time: 241535027
06-26 20:57:44.641 15914-15942/com.example.sharma.digimenu D/FA: Logging event (FE): user_engagement(_e), Bundle[{firebase_event_origin(_o)=auto, engagement_time_msec(_et)=2649, firebase_screen_class(_sc)=Home, firebase_screen_id(_si)=5270971596160237574}]
06-26 20:57:44.649 15914-15914/com.example.sharma.digimenu V/FA: onActivityCreated
06-26 20:57:44.682 15914-15942/com.example.sharma.digimenu D/FA: Logging event (FE): screen_view(_vs), Bundle[{firebase_event_origin(_o)=auto, firebase_previous_class(_pc)=Home, firebase_previous_id(_pi)=5270971596160237574, firebase_screen_class(_sc)=FoodList, firebase_screen_id(_si)=5270971596160237575}]
06-26 20:57:44.691 15914-15914/com.example.sharma.digimenu E/RecyclerView: No adapter attached; skipping layout
06-26 20:57:44.712 15914-15914/com.example.sharma.digimenu E/RecyclerView: No adapter attached; skipping layout
06-26 20:57:44.729 15914-15914/com.example.sharma.digimenu I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@35a28f6a time:94010814
06-26 20:57:44.731 15914-15942/com.example.sharma.digimenu V/FA: Activity resumed, time: 241535052

Answer 1

public class FoodList extends AppCompatActivity {

    RecyclerView recycler_food;
    RecyclerView.LayoutManager layoutManager;

    FirebaseDatabase database;
    DatabaseReference foodList;

    String categoryId = "";
    FirebaseRecyclerAdapter<Food, FoodViewHolder> adapter;

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

        database = FirebaseDatabase.getInstance();
        foodList = database.getReference("Foods");

        recycler_food = (RecyclerView) findViewById(R.id.recyclerfood);
        recycler_food.setHasFixedSize(true);
        layoutManager = new LinearLayoutManager(this);
        recycler_food.setLayoutManager(layoutManager);


        if (getIntent() != null)
            categoryId = getIntent().getStringExtra("CategoryId");
        if (categoryId != null && ! categoryId.isEmpty()) {
            loadListFood(categoryId);
        }

    }

    private void loadListFood(String categoryId) {

        Query food = FirebaseDatabase.getInstance().getReference("Foods").orderByChild("MenuId").equalTo(categoryId);

        FirebaseRecyclerOptions<Food> options =
                new FirebaseRecyclerOptions.Builder<Food>().setLifecycleOwner(this)
                        .setQuery(food, Food.class).build();

        adapter = new FirebaseRecyclerAdapter<Food, FoodViewHolder>(options) {
            @NonNull
            @Override
            public FoodViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

                View view = LayoutInflater.from(parent.getContext())
                        .inflate(R.layout.food_item, parent, false);
                return new FoodViewHolder(view);
            }

            @Override
            protected void onBindViewHolder(@NonNull FoodViewHolder holder, int position, @NonNull Food model) {
                holder.food_name.setText(model.getName());
                Picasso.with(getBaseContext()).load(model.getImage()).into(holder.food_image);
                final Food clickItem = model;
                //adapter.notifyDataSetChanged();
                holder.setItemClickListener(new ItemClickListener() {
                    @Override
                    public void onClick(View view, int position, boolean isLongClick) {
                        Toast.makeText(FoodList.this, "" + clickItem.getName(), Toast.LENGTH_SHORT).show();
                    }
                });
            }
        };
        recycler_food.setAdapter(adapter);

    }

}

回收器视图未连接空白屏幕

1 个答案: