Android spinner does not have ripple on button itself, just its options

I created a new Spinner in an Activity and as you described, the RippleDrawable is not applied to the Spinner using the v7 compatibility library or on Android 5.0+. This isn't surprising to me; Google often fails to implement its own design.

To have the affect, all I did was create a RippleDrawable in res/values-v21/ and set that to be the background on the Spinner using spinner.setBackgroundResource(R.drawable.spinner_background);. I'm sure you can also set this in your theme.