I got a simpler version but only support one viewType at a time

class SimpleViewHolder<T>(view: View) : RecyclerView.ViewHolder(view)

class RxAdapter<T>(
    @LayoutRes private val layoutId: Int,
    private val binding: (View, T) -> Unit
) : ListAdapter<T, SimpleViewHolder<T>>(DiffCallback<T>()) {
    private val signal by lazy { PublishSubject.create<Pair<Int, T>>() }
    val itemClicks by lazy { signal as Observable<Pair<Int, T>> }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SimpleViewHolder<T> =
        SimpleViewHolder(parent.inflate(layoutId, false))

    override fun onBindViewHolder(holder: SimpleViewHolder<T>, position: Int) {
        binding(holder.itemView, getItem(position))
        holder.itemView.setOnClickListener { signal.onNext(holder.adapterPosition to getItem(holder.adapterPosition)) }
    }

    private class DiffCallback<T> : DiffUtil.ItemCallback<T>() {
        override fun areItemsTheSame(oldItem: T, newItem: T): Boolean = oldItem == newItem

        override fun areContentsTheSame(oldItem: T, newItem: T): Boolean = oldItem == newItem
    }
}

Forgive me for combining Rx into it, as it suits my need.

that

DiffCallback

doesn’t handle modifying an item

When using data class, it actually can handle modified items, as the equals in data class is deep equal.

I’m saying your implementation of

DiffCallback

doesn’t handle it, think of what happens if an item changes one field