AnimalAdapter.kt

class AnimalAdapter(private val context: Context) :
    RecyclerView.Adapter<BaseViewHolder<*>>() {

    private var animalList = mutableListOf<Animal>()

    companion object {
        const val ITEMS_PER_PAGE = 4
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BaseViewHolder<*> {
                val itemWidth: Int = parent.width / ITEMS_PER_PAGE
                val view = LayoutInflater.from(context).inflate(R.layout.animals_row, parent, false)
                val layoutParams: ViewGroup.LayoutParams = view.layoutParams
                layoutParams.width = itemWidth
                view.layoutParams = layoutParams
                return AnimalViewHolder(view)
        }

    override fun getItemCount(): Int {
        return if (animalList.size > 0) animalList.size else 0
    }

    fun setAnimals(animalList:MutableList<Animal>){
        this.animalList = animalList
        notifyDataSetChanged()
    }

    fun getItem(position: Int): Animal {
        return animalList[position]
    }

    override fun onBindViewHolder(holder: BaseViewHolder<*>, position: Int) {
        val animalObj = animalList[position]
        when (holder) {
            is AnimalViewHolder -> holder.bind(animalObj,position)
            else -> throw IllegalArgumentException("No viewholder to show this data, did you forgot to add it to the onBindViewHolder?")
        }
    }

    inner class AnimalViewHolder(itemView: View) : BaseViewHolder<Animal>(itemView){
        override fun bind(item: Animal,position:Int) {
            Glide.with(context).load(item.image).centerCrop().placeholder(GlideProgress.setupCircularProgress(context)).into(itemView.animal_image)
            itemView.animal_name.text = item.name
        }
    }
}