Android, set LayoutParams programmatically

////- get LayoutParams and set Layout.
Button btn = new Button(this);

LayoutParams params = (LayoutParams)ib.getLayoutParams();

params.gravity = Gravity.CENTER_VERTICAL;




////- make LayoutParams and set Layout.

 LayoutParams lp = new LayoutParams(

                LayoutParams.MATCH_PARENT,

                LayoutParams.MATCH_PARENT);

image.setLayoutParams(lp);