I have a listview with custom listadapter, which populates the listview with a checkbox and some textviews. When the user selects a checkbox, I need a button bar to slide in
You want to use Animation xml resources.
Here is an example of an Animation xml that will 'slide' the object up from the bottom of the screen to where ever its place is within your layout:
You will put that in your res/anim folder then use this java code to animate your view:
slideUpIn = AnimationUtils.loadAnimation(this, R.anim.slide_up_in);
yourButtonBarView.startAnimation(slideUpIn);
You'll want to put the startAnimation call inside where you get the callback that your CheckBox has been checked.