Sample AdapterView.java

public class MainActivity extends Activity {
  @Override public void onCreate(Bundle savedInstance) {
    RecyclerView rv = findViewById(R.id.lv);
    RecyclerView.Adapter adapter = new SampleAdapter();
    rv.setAdapter(adapter);
    
    adapter.add(new Data());
    adapter.add(new Data());        // add Data
    adapter.nofityDatasetChanged(); // refresh Screen
  }
  
  private static class SampleAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    List<Data> datas;
    SampleAdapter() {
      datas = new ArrayLst<Data>();
    }
    
    public void add(Data data) {
      datas.add(data);
    }
    
    // ...
    
  }
}