android: how do I add padding to a LinearLayout inside a FrameLayout -

i have framelayout many children. 1 of children linearlayout. want width of linearlayout match_parent 90% so; means want add sort of paddingleft/right or margingleft/right. when add padding or margin, not applied in graphical layout. how do correctly?

<framelayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:background="@color/blue" >      <linearlayout         android:layout_width="match_parent"         android:layout_height="match_parent"         android:layout_gravity="center_horizontal"         android:background="@color/red"         android:marginleft="20dp"         android:marginright="20dp"         android:orientation="vertical" > .... 

you have

android:marginleft="20dp" android:marginright="20dp" 

instead change to:

android:layout_marginleft="20dp" android:layout_marginright="20dp" 

if still doesnot work, put layout inside layout , set margins other layout.