如何使用 RecyclerView 显示数组？

Question

class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {

    private final int listSize;
    private String[] list;

    public MyAdapter(int listSize, String[] list) {
        this.listSize = listSize;
        this.list = list;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        Context context = parent.getContext();
        LayoutInflater inflater = LayoutInflater.from(context);
        View view = inflater.inflate(R.layout.rv_item,parent,false);
        ViewHolder viewHolder = new ViewHolder(view);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        holder.bind(position);
    }

    @Override
    public int getItemCount() {
        return listSize;
    }

    class ViewHolder extends RecyclerView.ViewHolder {

        TextView item;
        Button button;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            item = itemView.findViewById(R.id.item_view);
            button = itemView.findViewById(R.id.button_item_view);
        }
        void bind(int index) {
            button.setText(String.valueOf(index));
            item.setText(list[index]);
        }
    }
}

In this adapter class I want to show a String array. The only problem is that the first element (with zero index) is missed on the screen, despite the fact that element exist beyond the screen (Sorry for such a big picture).

The buttons must be numbered with zero, so should the array be printed starting with zero element. How can I resolve this problem?

UPD: Here's the layout:

rv_item

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/item_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical|start"
        android:text="TextView"
        android:textSize="40sp" />

    <Button
        android:id="@+id/button_item_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical|end"
        android:layout_marginEnd="48dp"
        android:padding="10dp"
        android:text="INFO" />
</FrameLayout>

activity_top, in which recyclerView widget is used

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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=".TopLevelActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/listOfGoods"
        android:layout_width="409dp"
        android:layout_height="729dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:listitem="@layout/rv_item" />
</androidx.constraintlayout.widget.ConstraintLayout>

Answer 1

I know that it could be the same, but I would like to corroborate, try to change this code:

@Override
public int getItemCount() {
    return listSize;
}

For this:

@Override
public int getItemCount() {
    return list.length;
}

One more thing: try to debug this object this.list = list; and check if the array contains zero index element. If the array contains that element, probably it should something about layout as mentioned @Rui Alves.

Answer 2

Do not give fixed height of recyclerView

Correct Way:

<androidx.recyclerview.widget.RecyclerView
        android:id="@+id/listOfGoods"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:listitem="@layout/rv_items" />

PS: I have taken your example and run the app on api 29 work fine cheers! Also Do not make it listSize final , compiler will give error as you are not initializing