As others suggested, layout_margin# is the space between the parent's # edge and your view.
- # replaces "Left", "Right", "Top" or "Bottom"
Getting/setting margins worked for me with:
ViewGroup.MarginLayoutParams params = (ViewGroup.MarginLayoutParams) mView.getLayoutParams();
params.topMargin += 20;
mView.requestLayout(); // important
Of course, my View was indeed a ViewGroup and the parent was a ViewGroup as well. In most cases, you should cast your layout params to the parent's View class LayoutParams (in this case it's ViewGroup and RelativeLayout)