RelativeLayout.LayoutParams rp = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
rp.addRule(RelativeLayout.CENTER_IN_PARENT);
记录一下
Android 动态设置 layout_centerInParent
原文：http://www.cnblogs.com/IWings/p/6097134.html