MultiTypeAdapter.kt

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val list = findViewById<RecyclerView>(R.id.list)
        val adapter = MultiTypeAdapter()

        list.layoutManager = LinearLayoutManager(this)
        list.adapter = adapter

        adapter.registerType(
            String::class,
            TypeHolder(
                viewCreator = {
                    TextView(this).apply {
                        layoutParams = ViewGroup.LayoutParams(
                            ViewGroup.LayoutParams.MATCH_PARENT,
                            ViewGroup.LayoutParams.WRAP_CONTENT
                        )
                    }
                },
                viewBinder = { view, item ->
                    view.text = item
                },
                onClickListener = { view, item ->
                    Toast.makeText(this, item, Toast.LENGTH_SHORT).show()
                }
            )
        )

        adapter.registerType(
            Int::class,
            TypeHolder(
                viewCreator = {
                    EditText(this).apply {
                        layoutParams = ViewGroup.LayoutParams(
                            ViewGroup.LayoutParams.MATCH_PARENT,
                            ViewGroup.LayoutParams.WRAP_CONTENT
                        )
                    }
                },
                viewBinder = { view, item ->
                    view.setText(item.toString())
                },
                onClickListener = { view, item ->
                    Toast.makeText(this, item.toString(), Toast.LENGTH_SHORT).show()
                }
            )
        )

        adapter.addItems(listOf("A", "B", 1, "C", "D", 2, "E", "F", 3, "G"))
    }

}

class MultiTypeAdapter : RecyclerView.Adapter<ViewHolder>() {

    private val viewCreators = mutableMapOf<Int, TypeHolder<Any, View>>()
    private val types = mutableMapOf<KClass<*>, Int>()

    private val items = mutableListOf<Any>()

    fun addItems(items: List<Any>) {
        this.items.addAll(items)
        notifyDataSetChanged()
    }

    fun <T: Any, V : View> registerType(kClass: KClass<T>, typeHolder: TypeHolder<T, V>) {
        val type = kClass.hashCode()
        types[kClass] = type
        viewCreators[type] = typeHolder as TypeHolder<Any, View>
    }

    override fun onCreateViewHolder(parent: ViewGroup, type: Int): ViewHolder {
        val viewCreator = viewCreators[type]?.viewCreator ?: throw IllegalStateException("type not registered")
        return ViewHolder(viewCreator)
    }

    override fun getItemCount(): Int = items.size

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val type = getItemViewType(position)
        val typeHolder = viewCreators[type] ?: throw IllegalStateException("type not registered")
        val binder = typeHolder.viewBinder
        val item = items[position]

        binder(holder.itemView, item)
        holder.itemView.setOnClickListener { typeHolder.onClickListener(it, item) }
    }

    override fun getItemViewType(position: Int): Int {
        val item = items[position]
        return types[item::class] ?: throw IllegalStateException()
    }

}

class ViewHolder(viewCreator: () -> View) : RecyclerView.ViewHolder(viewCreator())

class TypeHolder<T, V : View>(
    val viewCreator: () -> V,
    val viewBinder: (V, T) -> Unit,
    val onClickListener: (V, T) -> Unit
)