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

    class ItemViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
        ImageView iv_product;
        TextView tv_description;
        Button btn_detail;

        public ItemViewHolder(View itemView){
            super(itemView);
            iv_product = itemView.findViewById( R.id.product_iv );
            tv_description = itemView.findViewById( R.id.description );
            btn_detail = itemView.findViewById( R.id.detail_btn );
            btn_detail.setOnClickListener( this );

        }

        // Button Function
        @Override
        public void onClick(View v){
            if (v == btn_detail){
                Intent i = new Intent( ctx, DetailActivity.class );
                i.putExtra( "image", image_list.get( getAdapterPosition() ) );
                i.putExtra( "text", description_list.get( getAdapterPosition() ) );
                ctx.startActivity( i );
            }
        }