you have to set the weight onto the children that are supposed to scale.
1 means 100% scaling by default, if you want 3 textvies to spread evenly set 0.33 as weight for each.
TableRow.layoutParams trlp = new LayoutParams(0, LayoutParams.MATCH_PARENT, 0.33f);
tv0.setLayoutParams(trlp);
...
tr.add(tv0);
...