android ExpandableListView animate drop down and up?

Question

Recently I meet a question is that how to let the ExpandableListView animate drop down and up. I search the result on StackOverflow. There's an answer:Android animate drop down/up view proper But it fit to the ListView. When I use it on ExpandableListView, it doesn't work. I think there must be someone who can solve this similar problem. If you have free time, could you tell me the solution or give tips to the question.