A simple RecyclerView subclass that supports providing an empty view which is displayed when the adapter has no data and hidden otherwise

BaseRecyclerView.kt

import android.content.Context
import android.support.v7.widget.RecyclerView
import android.util.AttributeSet
import android.view.View

/**
 * Created by zuhaib.ahmad on 2/22/2018.
 *
 * Simple RecyclerView subclass that supports providing an empty view (which
 * is displayed when the adapter has no data and hidden otherwise).
 */
class BaseRecyclerView : RecyclerView {

    var emptyView: View? = null

    private val dataObserver = object : RecyclerView.AdapterDataObserver() {
        override fun onChanged() {
            super.onChanged()
            updateEmptyView()
        }
    }

    constructor(c: Context) : super(c)

    constructor(c: Context, attrs: AttributeSet) : super(c, attrs)

    constructor(c: Context, attrs: AttributeSet, defStyle: Int) : super(c, attrs, defStyle)

    override fun setAdapter(adapter: RecyclerView.Adapter<*>?) {
        getAdapter()?.unregisterAdapterDataObserver(dataObserver)
        adapter?.registerAdapterDataObserver(dataObserver)
        super.setAdapter(adapter)
        updateEmptyView()
    }

    private fun updateEmptyView() {
        val showEmptyView = adapter.itemCount == 0
        emptyView?.visibility = if (showEmptyView) View.VISIBLE else View.GONE
        visibility = if (showEmptyView) View.GONE else View.VISIBLE
    }
}