Android Glossary
The following terms are used in these documents.
- .apk extension
- The extension for an Android package file, which typically contains all of the files
related to a single Android application. The file itself is a compressed collection
of an AndroidManifest.xml file, application code (.dex files), resource
files, and other files. A project is compiled into a single .apk file.
- .dex extension
- Android programs are compiled into .dex (Dalvik Executable) files, which
are in turn zipped into a single .apk file on the device. .dex files can
be created by automatically translating compiled applications written in
the Java programming language.
- Action
- A description of something that an Intent sender wants done. An action is
a string value assigned to an Intent. Action strings can be defined by Android
or by a third-party developer. For example, android.intent.action.VIEW
for a Web URL, or com.example.rumbler.SHAKE_PHONE for a custom application
to vibrate the phone.
- Activity
- A single screen in an application, with supporting Java code, derived from
the Activity class.
- adb
- Android Debug Bridge, a command-line debugging application shipped with the
SDK. It provides tools to browse the device, copy tools on the device, and
forward ports for debugging. See Listening
for and broadcasting global messages.
- Layout resource
- An XML file that describes the layout of an Activity screen.
- Manifest
- An XML file associated with each Application that describes the various activies,
intent filters, services, and other items that it exposes. See Nine-Patch Stretchable
Image for more information.
- Query String
- A type of URI. See the URI entry.
- Resource
- A user-supplied XML, bitmap, or other file, entered into an application build
process, which can later be loaded from code. Android can accept resources
of many types; see Resources for a full description.
Application-defined resources should be stored in the
res/ subfolders.
- Service
- A class that runs in the background to perform various persistent actions,
such as playing music or monitoring network activity.
- Theme
- A set of properties (text size, background color, and so on) bundled together
to define various default display settings. Android provides a few standard
themes, listed in R.style (starting with "Theme_").
- URIs
- Android uses URI strings both for requesting data (e.g., a list of contacts)
and for requesting actions (e.g., opening a Web page in a browser). Both
are valid URI strings, but have different values. All requests for data must
start with the string "content://". Action strings are valid URIs
that can be handled appropriately by applications on the device; for example,
a URI starting with "http://" will be handled by the browser.