recyclerview根本不显示。只显示文本视图。我查看了其他问题，并使用了以前问题的所有答案。其他的答案建议，回收器的宽度不能设置为wrap content，或者在设置layout manager和我满足这些条件之后应该调用setadapter。
主要活动

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        RecyclerView recyclerView = findViewById(R.id.main_recycler);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        final MainAdapter adapter = new MainAdapter();
        recyclerView.setAdapter(adapter);
        List<FirebaseProduct> firebaseProductList = new ArrayList<>();
        firebaseProductList = getData(); //Here is my Firebase code
        adapter.setList(firebaseProductList);
    }
 }

活动\u main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <TextView
        android:id="@+id/main_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/aktualne_produkty"
        android:gravity="center"
        android:background="@color/colorPrimary"
        android:textAppearance="@style/TextAppearance.AppCompat.Large">
    </TextView>
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/main_recycler"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        tools:listitem="@layout/card_main"
        android:layout_below="@id/main_text"/>
</RelativeLayout>

主适配器

public class MainAdapter extends RecyclerView.Adapter<MainAdapter.MainHolder> {
    private List<FirebaseProduct> productList = new ArrayList<>();
    @NonNull
    @Override
    public MainHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_main, parent, false);
        return new MainHolder(itemView);
    }
    @Override
    public void onBindViewHolder(@NonNull MainHolder holder, int position) {
        FirebaseProduct product = productList.get(position);
        Log.d("Prod holder", "name - " + product.getProductName());
        Log.d("Prod holder", "num - " + product.getProductNumber());
        holder.nameView.setText(product.getProductName());
        holder.numView.setText(product.getProductNumber());
    }
    @Override
    public int getItemCount() {
        return productList.size();
    }
    public void setProductList(List<FirebaseProduct> productList1){
        this.productList = productList1;
        notifyDataSetChanged();
    }
    public List<FirebaseProduct> getList(){
        return productList;
    }
    public static class MainHolder extends RecyclerView.ViewHolder{
        private TextView nameView;
        private TextView numView;
        public MainHolder(View itemView){
            super(itemView);
            nameView = itemView.findViewById(R.id.product_name);
            numView = itemView.findViewById(R.id.product_count);
        }
    }
}

主卡

<androidx.cardview.widget.CardView
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:cardCornerRadius="8dp">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <RelativeLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:background="@color/colorPrimary"
            android:layout_weight="3">
            <TextView
                android:id="@+id/product_name"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:gravity="center">
            </TextView>
            <TextView
                android:id="@+id/product_count"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@id/product_name">
            </TextView>
        </RelativeLayout>
        <ImageView
            android:id="@+id/product_image"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:contentDescription="@string/product_description">
        </ImageView>
    </LinearLayout>
</androidx.cardview.widget.CardView>