我们可以从RecyclerView的getItemCount（）中获得两种返回类型吗？

Question

This is my code. when i say return data1(); it runs fine but when i try return data1() + data3(); it gives me indexOutofBound Excception and i don't know the reason. Can someone help me please to find the reason of this error??
This is my MainActivity class code

 String[] data={"ok","this"};
int []images_id = new int[2];
    for(int i=0; i<2; i++){
        images_id[i] = getResources().getIdentifier("drawable/"+"candy_"+i, null, getPackageName());
    }
    ArrayList ok=new ArrayList();
    for (int y=0;y<data.length;y++)
    {
         ok.add(data[y]);
    }
    recyclerView.setLayoutManager(new LinearLayoutManager(getParent()));
    RecyclerWorkclass recyclerWorkclass=new RecyclerWorkclass(this,data,images_id);
    recyclerView.setAdapter(recyclerWorkclass);

And now this iss my RecyclerView class code

   ArrayList data1,data3;
Context context;
LayoutInflater inflater;
public RecyclerWorkclass(Context context,String[] dataoftext,int[] data2)
{
    inflater= LayoutInflater.from(context);
    this.context=context;
    data1=new ArrayList();
    data3=new ArrayList();
    for (int y=0;y<data2.length;y++)
    {
        this.data3.add(data2[y]);
    }
    for (int i=0;i<dataoftext.length;i++)
    {
        data1.add(dataoftext[i]);
    }
    Toast.makeText(context,"size is"+data3.size(),Toast.LENGTH_LONG).show();
}
@Override
public MyAdapter onCreateViewHolder(ViewGroup parent, int viewType) {
    View view=inflater.inflate(R.layout.recyclerwork_txt,parent,false);
    MyAdapter myAdapter=new MyAdapter(view);
    Toast.makeText(context,"view is "+viewType,Toast.LENGTH_LONG).show();
    return myAdapter;
}
@Override
public void onBindViewHolder(MyAdapter holder, int position) {
    holder.imageView.setImageResource((Integer) data3.get(position));
    holder.textView.setText((String)data1.get(position));
}
@Override
public int getItemCount() {
    return data1.size();
}
public class MyAdapter extends RecyclerView.ViewHolder {
    TextView textView;
    ImageView imageView;
    public MyAdapter(View itemView) {
        super(itemView);
        textView=itemView.findViewById(R.id.textview_phonecompany);
        imageView=itemView.findViewById(R.id.imageView2);}}
}

this code works fine but when i say

return data1.size() + data3.size();

it shows index out of bound error. why is that?

Answer 1

Is because when you put data1.size() + data3.size() in getItemCount() you not relative with your onBindViewHolder() and this is can be call anytime RecyclerView.Adapter Doc .

When your adapter call the onBindViewHolder() he throw this exception because this must call getItemCount() method and your two list as not the size declared in getItemCount() .

Explaination

@Override
public void onBindViewHolder(MyAdapter holder, int position) {
   holder.imageView.setImageResource((Integer) data3.get(position));
   holder.textView.setText((String)data1.get(position));
}

In this the position will more than your list because you double the size. So when he try to do data3.get(position) this exception append.