Kotlin version of https://gist.github.com/JakeWharton/5423616

BindableAdapter.kt

// Apache 2.0 licensed.
// Based on Jake Wharton's 'BindableAdapter.java' - https://gist.github.com/JakeWharton/5423616

import android.widget.BaseAdapter
import android.content.Context
import android.view.LayoutInflater
import kotlin.properties.Delegates
import android.view.View
import android.view.ViewGroup

/**
 * A base adapter that implements the new/bind view pattern.
 */
abstract class BindableAdapter<T>(private val context: Context) : BaseAdapter() {
  private val inflater: LayoutInflater by Delegates.lazy { LayoutInflater.from(context) }

  override abstract fun getItem(position: Int): T

  override fun getView(position: Int, view: View?, container: ViewGroup): View? {
    val viewToBind = view ?: newView(inflater, position, container)
    bindView(getItem(position), position, viewToBind)
    return viewToBind
  }

  override fun getDropDownView(position: Int, view: View?, container: ViewGroup?): View? {
    val viewToBind = view ?: newDropDownView(inflater, position, container)
    bindDropDownView(getItem(position), position, viewToBind)
    return viewToBind
  }

  abstract fun newView(inflater: LayoutInflater, position: Int, container: ViewGroup?): View

  abstract fun bindView(item: T, position: Int, view: View)

  open fun newDropDownView(inflater: LayoutInflater, position: Int, container: ViewGroup?): View =
    newView(inflater, position, container)

  open fun bindDropDownView(item: T, position: Int, view: View) =
    bindView(item, position, view)
}