android:layout_alignParentRight等对应的方法为addRule(int)
比如：
RelativeLayout.LayoutParams p=new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT,RelativeLayout.LayoutParams.WRAP_CONTENT);
p.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
p.addRule(RelativeLayout.CENTER_VERTICAL);
p.rightMargin=10;

设置Margin可以采用上面简洁的方式，或者下面这样：
MarginLayoutParams margins= new MarginLayoutParams(20,20);//item的宽高
margins.setMargins(10, 0,10 , 0);
LayoutParams lp = new LayoutParams(margins);