Select only one radiobutton in a recyclerview

Question

I have a recyclerview in which every item has 3 radiobuttons grouped in a radiogroup. Now a user can select only one radiobutton per item in recyclerview. But I want the user to select only one radiobutton throughout the recyclerview. How can this be achieved?

This is how it looks currently.

I would like to make it possible to check only 1 radiobutton throughout the recycler view. If 1st radio button in first item is checked and after that the user clicks on the 2nd radiobutton in 2nd item, then the 1st radiobutton in the 1st item should get unchecked.

Answer 1

I used this approach

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

    private List<OffersModel> offersList;
    private Context context;

    private int lastSelectedPosition = -1;

    public OffersRecyclerViewAdapter(List<OffersModel> offersListIn, Context ctx) {
        offersList = offersListIn;
        context = ctx;
    }

    @Override
    public OffersRecyclerViewAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.offer_item, parent, false);

        OffersRecyclerViewAdapter.ViewHolder viewHolder =
                new OffersRecyclerViewAdapter.ViewHolder(view);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(OffersRecyclerViewAdapter.ViewHolder holder, int position) {

        //since only one radio button is allowed to be selected,
        // this condition un-checks previous selections
        holder.selectionState.setChecked(lastSelectedPosition == position);
    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {

        public RadioButton selectionState;

        public ViewHolder(View view) {
            super(view);

         selectionState = (RadioButton) view.findViewById(R.id.offer_select);

            selectionState.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    lastSelectedPosition = getAdapterPosition();
                    notifyDataSetChanged();

                }
            });
        }
    }
}

Answer 2

KOTLIN 2021

Declare a RadioButton in a variable In your Adapter class

    private var lastCheckedRB: RadioButton? = null

Now In your Adapter class onBindViewHolder, Write OnclickListener to RadioButton

holder.YOURRADIOBUTTON.setOnClickListener {
        if (lastCheckedRB!=null){
            lastCheckedRB?.isChecked=false
        }
        lastCheckedRB = holder.YOURRADIOBUTTON
    }