Android : android RelativeLayout change height programmatically

i try change layout height programmatically.i have to buttons.in one button click i change my layout position and second button click i try to recive save position witch i was first time

     <RelativeLayout
        android:id="@+id/popaplayout"
        android:layout_width="fill_parent"
        android:layout_height="200dp" >

this is a my layout and in first button click i wrote

            RelativeLayout.LayoutParams parms = new RelativeLayout.LayoutParams(
                    RelativeLayout.LayoutParams.FILL_PARENT,
                    RelativeLayout.LayoutParams.FILL_PARENT);
            parms.addRule(RelativeLayout.BELOW, R.id.movies_title_layout);
            scrollpopap.setLayoutParams(parms);

            scrollpopap.setScrollingEnabled(true);

and second click

RelativeLayout.LayoutParams rel_btn = new RelativeLayout.LayoutParams(
                    ViewGroup.LayoutParams.WRAP_CONTENT, 300);
            rel_btn.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
            scrollpopap.setLayoutParams(rel_btn);
            scrollpopap.setScrollingEnabled(false);

in xml file i wrote height 200dp and programmatically 300 and there are different height.how i can wrote save height in programmatically?

if anyone knows solution please help me thanks