Author: Richard Lander -- firstname.lastname@example.org
License: Apache 2
This sample app demonstrates how to use ViewPager and ActionBar together. ViewPager provides a "swiping view" and ActionBar provides the tabs.
These two classes provide a very nice user experience together, but do not provide an intuitive approach to integration. This sample demonstrates how.
There are two primary integration challenges:
ActionBar and Viewpager come in different versions of the Android SDK and require special handling to work together.
Typically, ActionBar 'owns' its tab content. When used with ViewPager, ActionBar must give up content ownership to ViewPager, and just coordinate swipes with (essentially) fake tab transitions.
According to the docs, ActionBar first appeared in API level 11 and ViewPager in Support Library v4. The split between mainline and support libraries ends up being quite important. ActionBar works with Android.App.Fragment and related classes whereas Viewpager works with Android.Support.V4.App.Fragment. The trick is to change your Activity to derive from FragmentActivity, which satisfies both the regular and 'Support' API worlds.
The sample provides "shape" classes that satisfy the API requirements of ViewPager, and then uses lambdas to provide the required implementation. This approach ends up being quite nice, since the implementation can be written inline within the Activity without hiding it within separate classes. That's not a requirement, however.