How to add custom view inside RecyclerView.Adapter

Question

I have a RecyclerView and successfully adapted some data. I have a problem. In the onBindViewHolder method, I am trying to add a custom view in a linear layout. The custom view is successfully added, but in scroll up or down views are duplicated. I want to add only once with items.

My code:

public class TrainsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    public ArrayList<Train> trains;
    public Context context;
    private LayoutInflater inflater;
    public OnItemClickListener mOnItemClickListener;

    public void setmOnItemClickListener(OnItemClickListener mOnItemClickListener) {
        this.mOnItemClickListener = mOnItemClickListener;
    }


    public class GenericViewHolder extends RecyclerView.ViewHolder {
        public TextView stationName;
        public LinearLayout vagoncontainer;

        public GenericViewHolder(View view) {
            super(view);
            stationName = (TextView) view.findViewById(R.id.station_item_name);
            vagoncontainer = (LinearLayout) view.findViewById(R.id.vagon_container);


        }
    }

    public TrainsAdapter(Context context, ArrayList<Train> trains) {
        this.context = context;
        this.trains = trains;
        inflater = LayoutInflater.from(context);


    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.trains_adapter_item, parent, false);
        GenericViewHolder holder = new GenericViewHolder(view);
        return holder;


    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
        if (holder instanceof GenericViewHolder) {
            GenericViewHolder genericViewHolder = (GenericViewHolder) holder;
            Train train = trains.get(position);
            ArrayList<Vagons> vagons = train.getVagons();
            for (int i = 0; i < vagons.size(); i++) {
                LayoutInflater layoutInflater = LayoutInflater.from(context);
                LinearLayout vagonView = (LinearLayout) layoutInflater.inflate(R.layout.trains_vagon_child, null);
                Button button = (Button) vagonView.findViewById(R.id.button);
                if (vagons.get(i).getEnable().equals("1"))
                    button.setVisibility(View.VISIBLE);
                else
                    button.setVisibility(View.GONE);
                button.setText(vagons.get(i).getName() + " " + vagons.get(i).getAmount());
                genericViewHolder.vagoncontainer.addView(vagonView);
            }


            genericViewHolder.stationName.setText(train.getDeparture());

        }
    }

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

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

    public Train getItem(int position) {
        return trains.get(position);
    }

    public interface OnItemClickListener {
        void onItemClick(View view, int position);
    }
}

How can I solve my problem?

Why are you using loop inside onBindViewHolder ? Try removing that. — tahsinRupam, Mar 16 '17 at 07:48
because in my main data contains some Vagon's data and i want to add them by position @ tahsinRupam — BekaKK, Mar 16 '17 at 07:50
Do you want to make an expandable RecyclerView, with Train class as parent and Vagon class as child? — klaudiusnaban, Mar 16 '17 at 09:53
Since you want to inflate the layout only one time why don't you just added as a static layout instead of adding it to the list ? — Mo Hajr, Mar 16 '17 at 10:26

egoldx · Answer 1 · 2017-03-16T08:12:56.637

This will fix your problem, but it is not effective (it won't be scrolling smoothly for trains with large amount of vagons - inflating Views is expensive), since you will be removing and recreating views in that LinearLayout representing row in ListView. Either reconsider your row layout or create some pseudo recyling in your row view.

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
    if (holder instanceof GenericViewHolder) {
        GenericViewHolder genericViewHolder = (GenericViewHolder) holder;
        genericViewHolder.vagoncontainer.removeAllViews();
        Train train = trains.get(position);
        ArrayList<Vagons> vagons = train.getVagons();
        for (int i = 0; i < vagons.size(); i++) {
            LayoutInflater layoutInflater = LayoutInflater.from(context);
            LinearLayout vagonView = (LinearLayout) layoutInflater.inflate(R.layout.trains_vagon_child, null);
            Button button = (Button) vagonView.findViewById(R.id.button);
            if (vagons.get(i).getEnable().equals("1"))
                button.setVisibility(View.VISIBLE);
            else
                button.setVisibility(View.GONE);
            button.setText(vagons.get(i).getName() + " " + vagons.get(i).getAmount());
            genericViewHolder.vagoncontainer.addView(vagonView);
        }

        genericViewHolder.stationName.setText(train.getDeparture());
    }
}

score 0 · Answer 2 · answered Mar 16 '17 at 08:09

0

You can use core adapter

It's a simple lib to Support Any Type of items in recyclerview with no pain.

answered Mar 16 '17 at 08:09

FarshidABZ

3,860
4
32
63

score 0 · Answer 3 · edited May 23 '17 at 12:32

Basically RecyclerView reuses your viewHolder. So as per the RecyclerView doc here You have to reset the views everytime inside the onBindViewHolder() method,

And based on this

but in scroll up or down views are dublicated.I want to add only one time with items

you need to removeAllViews inside your vagonContainer viewgroup

so your bind holder will look like

if (holder instanceof GenericViewHolder) {
        GenericViewHolder genericViewHolder = (GenericViewHolder) holder;
        Train train = trains.get(position);
        ArrayList<Vagons> vagons = train.getVagons();

        // this is very important. removing all view
        genericViewHolder.vagoncontainer.removeAllViews();
......

How to add custom view inside RecyclerView.Adapter

3 Answers3