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Question

I have this recycler view adapter where the view has a radiobutton for each item. I want to get the item selected in my fragment. I can't figure out hoe to do that. Can someone help me out?

This is my adapter class:

public class croptypeadapter extends RecyclerView.Adapter<croptypeadapter.ViewHolder> {
    private List<croptype_list> croptypes;
    private Context context;
    Integer mSelectedItem = 0;

    public croptypeadapter(List<croptype_list> croptypes, Context context) {
        this.croptypes = croptypes;
        this.context = context;
    }

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

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        croptype_list ac=croptypes.get(position);
        Picasso.get().load(ac.getCropurl()).fit().into(holder.img);
        holder.txtview.setText(ac.getCropname());
        holder.radioButton.setChecked(position == mSelectedItem);
    }

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

    public class ViewHolder extends RecyclerView.ViewHolder{
        private ImageView img;
        TextView txtview;
        RadioButton radioButton;

        public ViewHolder(View itemView) {
            super(itemView);
            img= itemView.findViewById(R.id.imageview);
            txtview = itemView.findViewById(R.id.txtview);
            radioButton= itemView.findViewById(R.id.radio);

            View.OnClickListener l = new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    mSelectedItem = getAdapterPosition();
                    String data = croptypes.get(mSelectedItem).getCropname();
                    notifyItemRangeChanged(0, croptypes.size());
                }
            };
            itemView.setOnClickListener(l);
            radioButton.setOnClickListener(l);
        }
    }
}

And this is my fragment which has the recyclerview. I want to show the item selected in the recycler view in the Textview crop.

public class desc extends Fragment{

    private View view;
    RecyclerView vertical_recycler_view;
    private croptypeadapter croptypeadapter;
    private List<croptype_list> cropdata;
    ToggleButton toggleButton2;
    TextView crop;

    public static ApiInterface apiInterface;

    public desc() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        apiInterface = ApiClient.getApiClient().create(ApiInterface.class);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.fragment_zones, container, false);
        crop = view.findViewById(R.id.crop);

        vertical_recycler_view=view.findViewById(R.id.vertical_recycler_view);
        vertical_recycler_view.setLayoutManager(new LinearLayoutManager(getActivity()));

        apiInterface = ApiClient.getApiClient().create(ApiInterface.class);
        Call<List<croptype_list>>call=apiInterface.getcroptypes();
        call.enqueue(new Callback<List<croptype_list>>() {

            @Override
            public void onResponse(Call<List<croptype_list>> call, Response<List<croptype_list>> response) {

                cropdata=response.body();
                croptypeadapter=new croptypeadapter(cropdata,getActivity());
                vertical_recycler_view.setAdapter(croptypeadapter); }

            @Override
            public void onFailure(Call<List<croptype_list>> call, Throwable t) {

            }
        });

        toggleButton2.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

               if(isChecked){
                    toggleButton2.setBackgroundResource(R.drawable.uparrow);
                    vertical_recycler_view.setVisibility(View.VISIBLE);
                }else{
                    toggleButton2.setBackgroundResource(R.drawable.downarrow);
                    vertical_recycler_view.setVisibility(View.GONE);
                }
            }
        });
}

Answer 1

Set an onCheckedChanged Listener to the radio button and make the txtView in your class static so that you can access it in your adapterclass

static TextView crop

In you adapter class in the onBindViewholder

holder.radiobutton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        if (isChecked)
          this.mSelectedItem = position;
           desc.crop.setText("yourtext");
         }
    });

The onCheckedChanged Listener will updated the value of mSelectedItem so that even when the Viewholder is recycled the value will stay selected for the selected item only.