ItemDecoration for setting space around the RecyclerView items in Kotlin

PaddingItemDecoration.kt

import android.graphics.Rect
import android.support.v7.widget.RecyclerView
import android.view.View

class PaddingItemDecoration(val paddingTop: Int = 0,
                            val paddingRight: Int = 0,
                            val paddingBottom: Int = 0,
                            val paddingLeft: Int = 0,
                            val affectFirst: Boolean = true,
                            val affectEveryoneElse: Boolean = false,
                            val affectLast: Boolean = false,
                            val paddingTopByHeight: Boolean = true,
                            val paddingBottomByHeight: Boolean = true) : RecyclerView.ItemDecoration() {

    override fun getItemOffsets(outRect: Rect?, view: View?, parent: RecyclerView?, state: RecyclerView.State?) {
        if(view == null || parent == null)
            return

        val itemPosition = parent.getChildAdapterPosition(view)
        if(itemPosition == RecyclerView.NO_POSITION)
            return

        if((affectFirst && itemPosition == 0)
                || (affectLast && itemPosition == parent.adapter.itemCount - 1)
                || (affectEveryoneElse && itemPosition != 0 && itemPosition != parent.adapter.itemCount - 1))
            setOffset(outRect, view)
    }

    internal fun setOffset(rect: Rect?, view: View?) {
        val top = if(paddingTopByHeight) {
            view?.height?: paddingTop
        } else paddingTop

        val bottom = if(paddingBottomByHeight) {
            view?.height?: paddingBottom
        } else paddingBottom

        rect?.run {
            this.top = top
            this.bottom = bottom
            this.right = paddingRight
            this.left = paddingLeft
        }
    }
}