手风琴表格单元格——如何动态扩展/收缩uitableviewcell?

I am trying create an accordion type of uitableviewcell that, when the user selects the cell, it expands to display a detailed info view inline similar to how the digg app works. I initially tried replacing the current tablecell with a customcell in cellForRowAtIndex however the animation looks a bit choppy as you can see the cell being replaced and overall the effect doesnt work to well.I am trying create an accordion type of uitable