This component gives you ability to show your view above or below any other view located on the screen. It`s not blocking background like standart android dialog, everything located on the screen is focusable and clickable, even when pop up is opened. To close pop up just click on any object on the screen or call dismiss() method.
As an example find Quick Action Menu UI Design Pattern: http://www.androiduipatterns.com/p/android-ui-pattern-collection.html