Create recyclerview margin, end, middle, start margin of item

RecyclerMargin.kt

import android.graphics.Rect
import androidx.recyclerview.widget.RecyclerView
import android.view.View

/**
 * this widget add margin to start
 * @param outReact.left to change margin start
 *
 * */
class RecyclerMargin(
    private val start   : Int = 0,
    private val middle: Int = 16,
    private val end: Int = 0
): RecyclerView.ItemDecoration() {
    override fun getItemOffsets(
        outRect: Rect,
        view: View,
        parent: RecyclerView,
        state: RecyclerView.State
    ) {
        when {
            parent.getChildAdapterPosition(view) == 0 -> {
                outRect.left    = start
                outRect.right = middle
            }
            parent.getChildAdapterPosition(view) == parent.adapter?.itemCount?.minus(1) -> {
                outRect.left  = middle
                outRect.right = end
            }
            else -> {
                outRect.left  = middle
                outRect.right = middle
            }
        }
    }
}