How to access a TextView outside RecyclerView in Android?

Question

As per the image, in my main activity, I used a fragment and inside this fragment there is a horizontal RecyclerView, with some CardView(4 shown in the image below). The TextView is outside RecyclerView on the parent fragment. What I want is, access the TextView from the RecyclerView i.e. if I click a card inside the RecyclerView, the corresponding card text will show in the TextView.

Example: If I click CardView2 the TextView text will be "card2"....If I click CardView3 the TextView text will be "card3"

This is my Adapter Class:

public class ScanCodeSliderAdapter extends RecyclerView.Adapter<viewHolder> {

    private List<ScanCodeCardModel> scanCodeCardModels;
    private Context context;


    public ScanCodeSliderAdapter(List<ScanCodeCardModel> scanCodeCardModels, Context context) {
        this.scanCodeCardModels = scanCodeCardModels;
        this.context = context;
    }

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

    @Override
    public void onBindViewHolder(@NonNull final viewHolder holder, final int position) {
       
        holder.scanCodeSingleItemCardView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Toast.makeText(context, ""+position, Toast.LENGTH_SHORT).show();

            }
        });
    }

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

}

This is my ViewHolder Class:

public class viewHolder extends RecyclerView.ViewHolder {

    public CardView scanCodeSingleItemCardView;

    public viewHolder(@NonNull View itemView) {
        super(itemView);
        
        scanCodeSingleItemCardView = itemView.findViewById(R.id.scanCodeSingleItemCardView);
    }


}

What else can I add here to do that?

Answer 1

The best way to do this is via a click listener which will allow you to set up a communication between your RecyclerView items and the widgets or views outside of the recycler View.

To set up a listener you can use this example as a guide:

interface OnItemsClickListener{
     void onItemClick(ScanCodeCardModel scanCodeCardModels);
}

then create a listener variable inside your adapter class:

private OnItemsClickListener listener  = null;

and aa public method that will handle the or do the listening between your activity or fragment and the RecycerView Adapter like this

void setOnItemClickListener(OnItemsClickListener listener){
     this.listener = listener;
}

now go back into your onBindViewHolder inside the onClick() override method

 @Override
public void onBindViewHolder(@NonNull final viewHolder holder, final int position) {
   
    ScanCodeCardModels item =  scanCodeCardModels[position]

    holder.scanCodeSingleItemCardView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
           // Toast.makeText(context, ""+position, Toast.LENGTH_SHORT).show();
           if(listener != null){
               listener.onItemClick(item)
           }
        }
    });
}

that's all you need to do inside your Adapter class. Then proceed to your Fragment or Activity class, and connect to the listener

adapter.setOnItemClickListener(new AdapterName.OnItemClickListener(){
      @Override
      public void onItemClick(ScanCodeCardModel scanCodeCardModels){
           //Set your TextView here when card is Clicked on
           textView.setText(scanCodeModels.name)
      }
})

And that's all.