One way to think of a fragment is as a sub-activity. And in fact, the semantics of a fragment are a lot like an activity. A fragment can have a view hierarchy associated with it, and it has a life cycle much like an activity’s life cycle.
Android 6 – Menus and Action Bar
Working with Menu and Action Bar
Android 6 – Layout Managers
Android offers a collection of view classes that act as containers for views. These container classes are called layouts (or layout managers), and each implements a specific strategy to manage the size and position of its children.
Android 6 – Styles and Themes
Styles inline, create theme example code
Android 6 – List Controls
List Controls with Adapter code examples