From what I’ve been able to piece together, you have to add the view using LayoutParams.
LinearLayout linearLayout = new LinearLayout(this);
RelativeLayout.LayoutParams relativeParams = new RelativeLayout.LayoutParams(
LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
relativeParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);
parentView.addView(linearLayout, relativeParams);
All credit to sechastain, to relatively position your items programmatically you have to assign ids to them.
TextView tv1 = new TextView(this);
tv1.setId(1);
TextView tv2 = new TextView(this);
tv2.setId(2);
Then addRule(RelativeLayout.RIGHT_OF, tv1.getId());