FrameLayout
The simplest layout container is the FrameLayout. This container does not arrange
child views at all. It simply presents each view, one on top of the other. The order of
the views is based on their declaration in the XML file: Views declared later in the
file are drawn on top. Use this layout whenever you want to create overlapping views.
FrameLayout is especially useful when creating customized tappable elements.
You can use the FrameLayout to pair a button with an ImageView, setting the button
background to be transparent. This gives you more control over the padding and
scaling of button images than just setting a background does.