ListAdapter which has RecyclerView + DiffUtil.ItemCallback

HeroAdapter.kt

// build.gradle file 
// Recycler View (ConcatAdapter)
implementation 'androidx.recyclerview:recyclerview:1.3.0'

// HeroAdapter class
class HeroAdapter(private val context: Context) :
    ListAdapter<Hero, HeroAdapter.HeroViewHolder>(HeroDiffCallback) {
    private var currentPosition: Int = 0
    
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): HeroViewHolder {
        val view = LayoutInflater.from(context).inflate(R.layout.list_layout_heroes, parent, false)
        return HeroViewHolder(view)
    }

    override fun onBindViewHolder(holder: HeroViewHolder, position: Int) {
        val hero = getItem(position)
        holder.bind(context, hero, currentPosition, position)

        holder.textViewName.setOnClickListener {
            currentPosition = position
            notifyDataSetChanged()
        }
    }

    class HeroViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val textViewName: TextView = itemView.findViewById(R.id.textViewName)
        private val textViewRealName: TextView = itemView.findViewById(R.id.textViewRealName)
        private val textViewTeam: TextView = itemView.findViewById(R.id.textViewTeam)
        private val textViewFirstAppearance: TextView = itemView.findViewById(R.id.textViewFirstAppearance)
        private val textViewCreatedBy: TextView = itemView.findViewById(R.id.textViewCreatedBy)
        private val textViewPublisher: TextView = itemView.findViewById(R.id.textViewPublisher)
        private val textViewBio: TextView = itemView.findViewById(R.id.textViewBio)
        private val imageView: ImageView = itemView.findViewById(R.id.imageView)
        private val linearLayout: LinearLayout = itemView.findViewById(R.id.linearLayout)
        
        fun bind(context: Context, hero: Hero, currentPosition: Int, position: Int) {
            textViewName.text = hero.name
            textViewRealName.text = hero.realname
            textViewTeam.text = hero.team
            textViewFirstAppearance.text = hero.firstappearance
            textViewCreatedBy.text = hero.createdby
            textViewPublisher.text = hero.publisher
            textViewBio.text = hero.bio

            Glide.with(context).load(hero.imageurl).into(imageView)
            linearLayout.visibility = View.GONE

            if (currentPosition == position) {
                val animation = AnimationUtils.loadAnimation(context, R.anim.slide_down)
                linearLayout.visibility = View.VISIBLE
                linearLayout.animation = animation
            }
        }
    }

    object HeroDiffCallback : DiffUtil.ItemCallback<Hero>() {
        override fun areItemsTheSame(oldItem: Hero, newItem: Hero): Boolean {
            return oldItem.name == newItem.name
        }

        override fun areContentsTheSame(oldItem: Hero, newItem: Hero): Boolean {
            return oldItem == newItem
        }
    }
}

// MainActivity class
class MainActivity : AppCompatActivity() {
    private lateinit var heroHeaderAdapter: HeroHeaderAdapter
    private lateinit var heroAdapter: HeroAdapter
    private lateinit var concatAdapter: ConcatAdapter
    private lateinit var recyclerView: RecyclerView
    
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        recyclerView = findViewById(R.id.recyclerViewHeroes)
        recyclerView.setHasFixedSize(true)
        recyclerView.layoutManager = LinearLayoutManager(this)
        
        getHeroes()
    }
    
    private fun getHeroes() {
        val call = RetrofitClient.heroApi.getHeroes()
        
        call.enqueue(object : Callback<List<Hero>> {
            override fun onResponse(call: Call<List<Hero>>, response: Response<List<Hero>>) {
                val heroList = response.body()
                heroList?.let { list ->
                    heroAdapter = HeroAdapter(this@MainActivity)
                    heroHeaderAdapter = HeroHeaderAdapter(listOf(list.size.toString()), this@MainActivity)
                    concatAdapter = ConcatAdapter(heroHeaderAdapter, heroAdapter)
                    recyclerView.adapter = concatAdapter
                    heroAdapter.submitList(list)  // Wired with data
                }
            }

            override fun onFailure(call: Call<List<Hero>>, t: Throwable) {
                Toast.makeText(applicationContext, t.message, Toast.LENGTH_LONG).show()
            }
        })
    }
}