A RecyclerView Adapter for general purpose simple lists. It supports all common features including itemViewType.

RecyclerGeneralTypeAdapter

package com.ishaquehassan.recyclerviewgeneraladapter

import android.support.v7.widget.RecyclerView
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup

class RecyclerGeneralTypeAdapter<T>(val data:ArrayList<T>, private val layoutFiles:Map<Int,Int>, val onGetViewType:(Int, T)->Int, val onBindItem:(itemData:T, viewHolder:RecyclerGeneralTypeAdapter<T>.RecyclerGeneralViewHolder)->Unit) : RecyclerView.Adapter<RecyclerGeneralTypeAdapter<T>.RecyclerGeneralViewHolder>(){

    constructor(data:ArrayList<T>,layoutFile: Int,onBindItem:(T,RecyclerGeneralTypeAdapter<T>.RecyclerGeneralViewHolder)->Unit):this(data, mapOf(-10 to layoutFile),{_,_->-10},onBindItem)

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
        RecyclerGeneralViewHolder(
            LayoutInflater.from(parent.context).inflate(
                layoutFiles[viewType]!!,
                parent,
                false
            )
        )
    override fun getItemCount(): Int = data.size
    override fun onBindViewHolder(holder: RecyclerGeneralViewHolder, position: Int) = holder.onBindItem(data[position])
    override fun getItemViewType(position: Int): Int = onGetViewType(position,data[position])
    inner class RecyclerGeneralViewHolder(v:View) : RecyclerView.ViewHolder(v){
        fun onBindItem(item:T){
            onBindItem(item,this)
        }
    }

}

//Usage
data class ItemModel(val title:String)

//Simple Usage without ViewType
yourRecyclerViewInstance.adapter = RecyclerGeneralTypeAdapter(
    arrayListOf(ItemModel("Item 1"),ItemModel("Item 2")),
    R.layout.your_item_layout
){ itemData,viewHolder ->
    val itemView = viewHolder.itemView
    val position = viewHolder.adapterPosition
    itemView.findViewById<TextView>(R.id.item_title_tv).text = itemData.title
}

//Adavanced Usage with ViewType
yourRecyclerViewInstance.adapter = RecyclerGeneralTypeAdapter(
    arrayListOf(ItemModel("Item 1"),ItemModel("Item 2")),
    mapOf(
        // Key = ViewTypw , Value = Layout Resource File
        1 to R.layout.your_item_layout_1,
        2 to R.layout.your_item_layout_2
    ),{position,itemData ->
        
        //ViewType Decision on basis of item data
        if(itemData.title == "Item 1"){1}
        
        //ViewType Decision on basis of item position
        else if(position == 1){2}
        
        //Default ViewType should be returned too
        else {1}
    }
){ itemData,viewHolder ->
    val itemView = viewHolder.itemView
    val position = viewHolder.adapterPosition
    itemView.findViewById<TextView>(R.id.item_title_tv).text = itemData.title
}

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