Bind your Android data-binding ObservableList to a RecyclerView

RecyclerViewAdapterOnListChangedCallback.kt

import android.databinding.ObservableList
import android.support.v7.widget.RecyclerView

/**
 * Links an [ObservableList] to a [RecyclerView], so that whenever the list is changed, the view is
 * updated.
 */
class RecyclerViewAdapterOnListChangedCallback<T>(
        private val adapter: RecyclerView.Adapter<*>
) : ObservableList.OnListChangedCallback<ObservableList<T>>() {
    override fun onChanged(sender: ObservableList<T>) {
        adapter.notifyDataSetChanged()
    }

    override fun onItemRangeRemoved(sender: ObservableList<T>, positionStart: Int, itemCount: Int) {
        adapter.notifyItemRangeRemoved(positionStart, itemCount)
    }

    override fun onItemRangeMoved(sender: ObservableList<T>, fromPosition: Int, toPosition: Int, itemCount: Int) {
        repeat(itemCount) { i ->
            adapter.notifyItemMoved(fromPosition + i, toPosition + i)
        }
    }

    override fun onItemRangeInserted(sender: ObservableList<T>, positionStart: Int, itemCount: Int) {
        adapter.notifyItemRangeInserted(positionStart, itemCount)
    }

    override fun onItemRangeChanged(sender: ObservableList<T>, positionStart: Int, itemCount: Int) {
        adapter.notifyItemRangeChanged(positionStart, itemCount)
    }
}

/** Convenience function to link an [ObservableList] and a [RecyclerView.Adapter]. */
fun <T> ObservableList<T>.subscribeRecycler(adapter: RecyclerView.Adapter<*>) {
    addOnListChangedCallback(RecyclerViewAdapterOnListChangedCallback(adapter))
}