Duplicates in recycler view.

[pharma-vie]

How to make the lise authorize no duplicates. It is an element exists twice it appears only once.

MyAdapter

public abstract class MyAdapter<VH extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<VH> {

  public ArrayList<Players> items = new ArrayList<>();

  public CityListAdapter() {
    setHasStableIds(true);
  }

  public void add(Players object) {
    items.add(object);
    notifyDataSetChanged();
  }

  public void add(int index, Players object) {
    items.add(index, object);
    notifyDataSetChanged();
  }

  public void addAll(Collection<? extends Players> collection) {
    if (collection != null) {
      items.addAll(collection);
      notifyDataSetChanged();
    }
  }


  public Players getItem(int position) {
    return items.get(position);
  }

  @Override
  public long getItemId(int position) {
    return position;
  }

  @Override
  public int getItemViewType(int position) {
    return position;
  }

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

}

Holder:

public class CityListWithHeadersAdapter extends CityListAdapter<RecyclerView.ViewHolder>
        implements StickyRecyclerHeadersAdapter<RecyclerView.ViewHolder> {



    //item_title:

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.item_view, parent, false);
        return new MyViewHolder (view);
    }

    @Override
    public void onBindViewHolder (RecyclerView.ViewHolder holder, final int position) {
        String name = getItem (position).getName();
        ((MyViewHolder)holder).item_title.setText(name);

        String name2 = getItem (position).getClub();
        ((MyViewHolder)holder).item_subtitle.setText(name2);

        ColorGenerator generator = ColorGenerator.MATERIAL;
        int color1 = generator.getRandomColor();

        TextDrawable drawable = TextDrawable.builder()
                .beginConfig()
                .height(60)
                .width(60)
                .endConfig()
                .buildRound(""+name.charAt(0), color1);
        ((MyViewHolder)holder).drawable.setImageDrawable(drawable);

    }

    //header_view:
    @Override
    public long getHeaderId(int position) {
        return getItem(position).getCategory().length();
    }

    @Override
    public RecyclerView.ViewHolder onCreateHeaderViewHolder(ViewGroup parent) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.header_view, parent, false);
        return new MyViewHolder (view);
    }

    @Override
    public void onBindHeaderViewHolder(RecyclerView.ViewHolder holder, int position) {

        String name = getItem (position).getCategory ();
        ((MyViewHolder)holder).header_title.setText (name);

        String name2 = getItem (position).getClub ();
        ((MyViewHolder)holder).header_subTitle.setText (name2);
    }

    //MyViewHolder:
    public class MyViewHolder extends RecyclerView.ViewHolder {
        ImageView drawable;
        private final TextView item_title;
        private final TextView item_subtitle;

        private final TextView header_subTitle;
        private final TextView header_title;

        MyViewHolder(View itemView) {
            super (itemView);

            header_title = itemView.findViewById (R.id.header_title);
            header_subTitle = itemView.findViewById (R.id.header_subTitle);
            drawable = itemView.findViewById (R.id.drawable);
            item_title = itemView.findViewById (R.id.item_title);
            item_subtitle = itemView.findViewById (R.id.item_subtitle);


            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                }
            });

            itemView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    return false;
                }
            });
        }

    }

    //color:
    private int getRandomColor() {
        SecureRandom rgen = new SecureRandom();
        return Color.HSVToColor(2000, new float[]{
                rgen.nextInt(35), 1, 1
        });
    }


}

[mtariquekhan]

I am also facing the same problem. Having the Duplicates value