Book Image

Creating Dynamic UI with Android Fragments

By : Jim Wilson
Book Image

Creating Dynamic UI with Android Fragments

By: Jim Wilson

Overview of this book

To create a dynamic and multi-pane user interface on Android, you need to encapsulate UI components and activity behaviors into modules that you can swap into and out of your activities. You can create these modules with the fragment class, which behaves somewhat like a nested activity that can define its own layout and manage its own lifecycle. When a fragment specifies its own layout, it can be configured in different combinations with other fragments inside an activity to modify your layout configuration for different screen sizes (a small screen might show one fragment at a time, but a large screen can show two or more). Creating Dynamic UI with Android Fragments shows you how to create modern Android applications that meet the high expectations of today's users. You will learn how to incorporate rich navigation features like swipe-based screen browsing and how to create adaptive UIs that ensure your application looks fantastic whether run on a low cost smartphone or the latest tablet. This book looks at the impact fragments have on Android UI design and their role in both simplifying many common UI challenges and providing new ways to incorporate rich UI behaviors. You will learn how to use fragments to create UIs that automatically adapt to device differences. We look closely at the roll of fragment transactions and how to work with the Android back stack. Leveraging this understanding, we then explore several specialized fragment-related classes like ListFragment and DialogFragment as well as rich navigation features like swipe-based screen browsing.
Table of Contents (13 chapters)

Dynamically managing fragments


The process of dynamically managing fragments commonly involves multiple steps. The steps may be simple like removing one fragment and adding another, or they may be more complex, involving the removal and addition of multiple fragments. In any case, we need to be certain that all dynamic changes to the fragments within an activity that constitute a shift from one application screen to the next occur together as a single unit of work. Android does this by grouping the steps into transactions using the FragmentTransaction class.

Conceptually, the FragmentTransaction class behaves in a manner consistent with other transaction models: start the transaction, identify the desired changes, and commit the transaction once all changes within that unit of work are identified.

When we're ready to make changes, we start a new FragmentTransaction instance by calling the beginTransaction method on the activity's FragmentManager instance, which returns back a reference to...