API Level: 8
Android 2.2 is a minor platform release including user features, developer features, API changes, and bug fixes. For information on developer features and API changes, see the Framework API section.
For developers, the Android 2.2 platform is available as a downloadable component for the Android SDK. The downloadable platform includes an Android library and system image, as well as a set of emulator skins and more. To get started developing or testing against Android 2.2, use the Android SDK Manager to download the platform into your SDK.
For a list of new user features and platform highlights, see the Android 2.2 Platform Highlights document.
The Android 2.2 platform delivers an updated version of the framework API. The Android 2.2 API is assigned an integer identifier — 8 — that is stored in the system itself. This identifier, called the "API Level", allows the system to correctly determine whether an application is compatible with the system, prior to installing the application.
To use APIs introduced in Android 2.2 in your
application, you need to set the proper value, "8", in the
android:minSdkVersion attributes of the
element in your application's manifest.
For more information about how to use API Level, see the API Levels document.
Framework API Changes
The sections below provide information about changes made to the application framework API provided by the Android 2.2 platform.
App installation on external storage media
The Android platform now allows applications to request installation onto the device's external storage media (such as the SD card), as an alternative to installation onto the device's internal memory.
Application developers can express the preferred installation location for
their applications by means of a new attribute of
in the manifest file,
android:installLocation. The attribute supports three values:
"auto". At install time, the system checks the value of
android:installLocation and installs the application
.apk according to the preferred location, if possible. If the
application has requested external installation, the system installs it into a
private, encrypted partition in the external media. Once an application .apk is
installed externally, the system lets the user change the storage location of
the .apk and move it onto the device's internal memory if needed (and vice
versa), through Manage Applications in the user settings.
By default, the system installs all applications onto the device's internal
memory, except for those that explicitly request external installation. This
means that the system will always install legacy applications onto internal
memory, since they do not have access to the
android:installLocation attribute. However, it is possible to
configure and compile a legacy application such that it is installed internally
on older versions of the platform and externally on Android 2.2 and later
platforms, if necessary.
Note that requesting installation onto the device's external media is not suitable for all applications, particularly because the external media may be removable and unmounting/remounting may disrupt the user experience and system settings.
For more information about setting a preferred install location for your application, including a discussion of what types of applications should and should not request external installation, please read the App Install Location document.
The platform now provides a generalized backup service that applications can use to backup and restore user data, to ensure that users can maintain their data when switching devices or reinstalling the application. The Backup Manager handles the work of transporting the application data to and from the backup storage area in the cloud. The Backup Manager can store any type of data, from arbitrary data to files, and manages backup and restore operations in an atomic manner. For more information, see Data Backup.
- New OpenGL ES 2.0 APIs in
ETC1Util.ETC1Textureclasses and utility methods for using ETC1 for texture compression.
YUV image format APIto enable compression from YUV to JPEG and manipulation of YUV data.
- New APIs in
android.media.AudioManagerfor managing audio focus, transport control, transient loss of audio focus, ducking.
- New broadcast intent for routing audio to SCO —
ACTION_SCO_AUDIO_STATE_CHANGEDwith extras indicating new state.
- New APIs in
SoundPoolto detect completion of sound-loading.
- New APIs in
SoundPoolfor auto pause and resume.
- New APIs in
MediaRecorderfor specifying audio settings for number of channels, encoding and sampling rates, sampling rate.
- New APIs for adding files to the media database, so that they are automatically scanned. See
Speech recognition and third-party recognition engines
- The platform provides new speech-recognition APIs that allow applications to have a richer interaction with the available voice recognizer. For example, the APIs are sufficient to integrate voice recognition deeply into an IME.
- The platform also provides a
RecognitionServicebase class that lets third-party developers create plug-in recognition engines.
RecognitionListenerinterface to receive callbacks.
RecognizerIntentextras that let a requester app specify details as preferred language, minimum length in milliseconds, and so on.
Camera and camcorder
- Changes to camera preview API to improve efficieny of preview pipeline.
- New display orientation for camera (it can now work in portrait orientation).
- New APIs in
android.hardware.Camerafor managing zoom level.
- New APIs
android.hardware.Camera.Parametersfor querying and setting device camera settings such as focal length, exposure, zoom level, view angle, and others.
thumbnailutility for video and image thumbnails.
CamcorderProfileclasses enable apps to determine device hardware camera capabilities.
- New support in
android.media.ExifInterfacefor retrieving GPS and focal length.
Device policy manager
New device policy management APIs allow developers to write "device
administrator" applications that can control security features of the device,
such as the minimum password strength, data wipe, and so on. Users can select
the administrators that are enabled on their devices. For more information, see
android.app.admin classees or the example
application code in DeviceAdminSample.java.
- New UI modes "car mode" and "night mode" and
UiModeManagerlet applications adjust their application UI for specific user modes.
ScaleGestureDetectorthat lets Views detect and handle transformation gestures that involve more than one pointer (multitouch) using the supplied MotionEvents.
- Improvements in the way that multitouch events are reported in
- The layout attribute
fill_parentis renamed to
match_parent. This affects both XML and Java code (see
ViewGroup.LayoutParams). Note that the platform will continue to honor uses of
fill_parentin legacy applications.
- New layout attributes
tabStripLeftlet developers customize the bottom strip of TabWidgets.
- Better support for managed dialogs in Activity.
Accounts and sync
- New method
AddPeriodicSync()lets you schedule a periodic sync with a specific account, authority, and extras at the given frequency.
New manifest elements and attributes
- For specifying the application's preferred install location (see App Installation on External Storage Media, above):
android:installLocationattribute of the
<manifest>element. Specifies the default install location defined by an application.
- For managing user data backup (see Backup manager, above, for more information):
android:backupAgentattribute of the
<application>element. Specifies the component name of the BackupAgent subclass provided by the application to handle backup/restore operations, if any.
android:restoreAnyVersionattribute of the
<application>element. Boolean value that indicates whether the application is prepared to attempt a restore of any backed-up dataset, even if the backup is apparently from a newer version of the application than is currently installed on the device.
- For managing the platform's JIT compiler:
android:vmSafeModeattribute of the
<application>element. Boolean value that specifies whether to disable JIT compiler optimizations when running the application.
android.permission.BIND_DEVICE_ADMIN— Any device administration broadcast receiver must require this permission, to ensure that only the system can interact with it.
android.permission.KILL_BACKGROUND_PROCESSES— Allows an application to call
WallpaperServicemust require this permission, to ensure that only the system can interact with it.
android.permission.SET_TIME— Allows an application to set the system time.
API differences report
For a detailed view of all API changes in Android 2.2 (API Level 8), see the API Differences Report.