Java Reference
In-Depth Information
Figure 12-1.
Android's layered architecture consists of several major parts.
Users care about apps, and Android ships with a variety of useful core apps, which
includeBrowser,Contacts,andPhone.AllappsarewritteninJava.Appsformthetop
layer of Android's architecture.
Directlybeneaththeapplayeristhe
application framework
,asetofhigh-levelbuild-
ing blocks for creating apps. The application framework is preinstalled on Android
devices and consists of the following components:
•
Activity Manager
:Thiscomponentprovidesanapp's
lifecycle
andmaintains a
sharedactivitystackfornavigatingwithinandamongapps.(Idiscussbothcon-
cepts later in this chapter when I present activities.)
•
Content Providers
:Thesecomponentsencapsulatedata(e.g.,theBrowserapp's
bookmarks) that can be shared among apps.
