snippet from me trying to get color states working for buttons based off https://gist.github.com/milosmns/6566ca9e3b756d922aa5

button_color.kt

  fun getPressedColorSelector(normalColor: Int, pressedColor: Int, disabledColor: Int): ColorStateList {
        val states =
                arrayOf(intArrayOf(android.R.attr.state_pressed),  // pressed
                        intArrayOf(-android.R.attr.state_enabled), // disabled
                        intArrayOf(android.R.attr.state_focused), //focused
                        intArrayOf() //empty aka normal

                )

        val colors = intArrayOf(
                pressedColor,
                disabledColor,
                pressedColor,
                normalColor
        )

        return ColorStateList(states, colors)
    }

  /**
     * Very similar to [.createContrastStateDrawable] but
     * creates a Ripple drawable available in Lollipop.
     *
     * @param normal Color normal state of the drawable to this color
     * @param clickedBackground Background color of the View that will show when view is clicked
     * @param original This drawable will be contrasted to the `clickedBackground` color on press
     * @return The Ripple drawable that is in contrast with the on-click background color
     */
    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    fun createContrastRippleDrawable(normal: Int, clickedBackground: Int, disabledColor: Int, original: Drawable?): Drawable {
        if (original == null) {
            return createRippleDrawable(normal, clickedBackground, null)
        }

        //return RippleDrawable(ColorStateList.valueOf(clickedBackground), original, ColorDrawable(clickedBackground))
          
        return RippleDrawable(getPressedColorSelector(normal, clickedBackground, disabledColor), original, ColorDrawable(clickedBackground))
        //.........................^
    }

    /**
     * Creates a new `RippleDrawable` used in Lollipop and later.
     *
     * @param normalColor Color for the idle ripple state
     * @param rippleColor Color for the clicked, pressed and focused ripple states
     * @param bounds Clip/mask drawable to these rectangle bounds
     * @return A fully colored RippleDrawable instance
     */
    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    fun createRippleDrawable(normalColor: Int, rippleColor: Int, bounds: Rect?): Drawable {
        var maskDrawable: ColorDrawable? = null
        if (bounds != null) {
            maskDrawable = ColorDrawable(Color.WHITE)
            maskDrawable.bounds = bounds!!
        }

        return if (normalColor == Color.TRANSPARENT) {
            RippleDrawable(ColorStateList.valueOf(rippleColor), null, maskDrawable)
        } else {
            RippleDrawable(ColorStateList.valueOf(rippleColor), ColorDrawable(normalColor), maskDrawable)
        }
    }