sample_of_StyledRecyclerView.kt

constructor(...) : super(...) {
    val a = context.theme.obtainStyledAttributes(
        attrs,
        R.styleable.StyledRecyclerView, 0, 0)
    decorateView(a, getOrientation(attrs))
    a.recycle()
}

private fun decorateView(
    typedArray: TypedArray,
    orientation: Int
) {
    // Divider and the mode
    if (typedArray.hasValue(R.styleable.StyledRecyclerView_rvDividerDrawable)) {
        val dividerDrawable = typedArray.getDrawable(R.styleable.StyledRecyclerView_rvDividerDrawable)
        val dividerMode = typedArray.getInt(R.styleable.StyledRecyclerView_rvDividerMode, DividerMode.SHOW_DIVIDER_NONE)

        val decoration = DrawableDividerDecoration(
            dividerDrawable = dividerDrawable,
            dividerMode = dividerMode)
        addItemDecoration(decoration)
    }

    // Preview list item
    if (isInEditMode) {
        layoutManager = LinearLayoutManager(context, orientation, false)
    }
}