You can basically use RelativeLayout or LinearLayout it will still work,but the answer of your question is in FrameLayout‘s documentation :
FrameLayout is designed to block out an area on the screen to display
a single item. Generally, FrameLayout should be used to hold a single
child view, because it can be difficult to organize child views in a
way that’s scalable to different screen sizes without the children
overlapping each other. You can, however, add multiple children to a
FrameLayout and control their position within the FrameLayout by
assigning gravity to each child, using the android:layout_gravity
attribute.
You can read more about FrameLayout here : FrameLayout/Android Developers