How to create custom spinner like border around the spinner with down triangle on the right side?

Question

I want to develop custom spinner like line around spinner with triangle at right bottom corner.
like following image

Answer 1

It's super easy you can just add this to your Adapter -> getDropDownView

getDropDownView:

convertView.setBackground(getContext().getResources().getDrawable(R.drawable.bg_spinner_dropdown));

bg_spinner_dropdown: