无法识别我在 RecyclerView.Adapter 中创建的方法

Question

I created my own class called RecyclerviewAdapter.java that extends RecyclerView.Adapter<> , and I created a method in that class

public void setItemCount(int i){
    size=i;
}

My RecyclerView works, and I want user to be able to set how many items to be displayed in RecyclerView. In MainActivity, when I call adapter.setItemCount(2) , it says Cannot resolve method 'setItemCount' in 'Adapter' , also Method 'setItemCount(int)' is never used . I don't know how to solve it.
Here are my files.

MainActivity.java

RecyclerView recycler;
RecyclerView.Adapter adapter;
RecyclerView.LayoutManager manager;
ArrayList<RecyclerviewItem> list=new ArrayList<>();
    list.add(new RecyclerviewItem(R.drawable.hoversfw,"Title","Description"));
    manager=new LinearLayoutManager(this);
    adapter=new RecyclerviewAdapter(list);
    recycler=findViewById(R.id.recycler);
    recycler.setHasFixedSize(true);
    recycler.setLayoutManager(manager);
    recycler.setAdapter(adapter);
if(!count.getText().toString().equals("")) {
    int c= Integer.parseInt(count.getText().toString());
    adapter.setItemCount(c);
}

RecyclerviewAdapter.java

public class RecyclerviewAdapter extends RecyclerView.Adapter<RecyclerviewAdapter.RecyclerviewHolder> {
private ArrayList<RecyclerviewItem> list;
private int size;

@NonNull
@Override
public RecyclerviewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View v= LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_item,parent,false);
    RecyclerviewHolder holder=new RecyclerviewHolder(v);
    return holder;
}


public RecyclerviewAdapter(ArrayList<RecyclerviewItem>mlist){
    list=mlist;
    size=1;
}

public void setItemCount(int i){
    size=i;
}

@Override
public void onBindViewHolder(@NonNull RecyclerviewHolder holder, int position) {
    RecyclerviewItem item=list.get(position);
    holder.image.setImageResource(item.getImageResource());
    holder.title.setText(item.getTitle());
    holder.description.setText(item.getDescription());
}

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

public static class RecyclerviewHolder extends RecyclerView.ViewHolder{
    public ImageView image;
    public TextView title;
    public TextView description;

    public RecyclerviewHolder(@NonNull View itemView) {
        super(itemView);
        image=itemView.findViewById(R.id.img);
        title=itemView.findViewById(R.id.title);
        description=itemView.findViewById(R.id.description);
    }
}
}

RecyclerviewItem.java

public class RecyclerviewItem {
private int imageResource;
private String title;
private String description;

public RecyclerviewItem(int mimageResource, String mtitle, String mdescription){
    imageResource=mimageResource;
    title=mtitle;
    description=mdescription;
}

public int getImageResource(){
    return imageResource;
}

public String getTitle(){
    return title;
}

public String getDescription(){
    return description;
}
}

Answer 1

You are declaring RecyclerView Adapter with RecyclerView.Adapter although it should be RecyclerviewAdapter

RecyclerView.Adapter is an SDK class, but RecyclerviewAdapter is yours.