API Level: 9
For developers, the Android 2.3
GINGERBREAD)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 2.3,
use the Android SDK Manager to download the platform into your SDK.
The sections below provide a technical overview of what's new for developers in 2.3, including new features and changes in the framework API since the previous version.
The platform now includes a SIP protocol stack and framework API that lets developers build internet telephony applications. Using the API, applications can offer voice calling features without having to manage sessions, transport-level communication, or audio — these are handled transparently by the platform's SIP API and services.
The SIP API is available in the
package. The key class is
SipManager, which applications
use to set up and manage SIP profiles, then initiate audio calls and receive
audio calls. Once an audio call is established, applications can mute calls,
turn on speaker mode, send DTMF tones, and more. Applications can also use the
SipManager to create generic SIP connections.
The platform’s underlying SIP stack and services are available on devices at
the discretion of the manufacturer and associated carrier. For this reason,
applications should use the
isApiSupported() method to check whether SIP support is available, before
exposing calling functionality to users.
To use the SIP API, applications must request permission from the user by
android:name="android.permission.USE_SIP"> in their manifest files.
Additionally, developers can request filtering on Google Play, such that
their applications are not discoverable to users whose devices do not include
the platform’s SIP stack and services. To request filtering, add
android:name="android.software.sip.voip"> to the application manifest.
For more information, read the SIP developer guide.
Near Field Communications (NFC)
Android 2.3 includes an NFC stack and framework API that lets developers read NDEF tags that are discovered as a user touches an NFC-enabled device to tag elements embedded in stickers, smart posters, and even other devices.
The platform provides the underlying NFC services that work with the device hardware to discover tags when they come into range. On discovering a tag, the platform notifies applications by broadcasting an Intent, appending the tag's NDEF messages to the Intent as extras. Applications can create Intent filters to recognize and handle targeted tags and messages. For example, after receiving a tag by Intent, applications extract the NDEF messages, store them, alert the user, or handle them in other ways.
The NFC API is available in the
android.nfc package. The key classes are:
NfcAdapter, which represents the NFC hardware on the device.
NdefMessage, which represents an NDEF data message, the standard format in which "records" carrying data are transmitted between devices and tags. Applications can receive these messages from
NdefRecord, delivered in an
NdefMessage, which describes the type of data being shared and carries the data itself.
NFC communication relies on wireless technology in the device hardware, so
support for the platform's NFC features on specific devices is determined by
their manufacturers. To determine the NFC support on the current device,
applications can call
NfcAdapter. The NFC API is always present,
however, regardless of underlying hardware support.
To use the NFC API, applications must request permission from the user by
android:name="android.permission.NFC"> in their manifest files.
Additionally, developers can request filtering on Google Play, such that
their applications are not discoverable to users whose devices do not support
NFC. To request filtering, add
android:required="true"> to the application's manifest.
To look at a sample application that uses the NFC API, see NFCDemo.
Gyroscope and other sensors
Android 2.3 adds platform and API support for several new sensor reading types — gyroscope, rotation vector, linear acceleration, gravity, and barometer. Developers can use the new sensor readings to create applications that respond quickly and smoothly to precise changes in device position and motion. The Sensor API reports gyroscope and other sensor changes to interested applications, whether they are running on the application framework or in native code.
Note that the specific set of hardware sensors available on any given device varies at the discretion of the device manufacturer.
Developers can request filtering on Google Play, such that their
applications are not discoverable to users whose devices do not offer a
gyroscope sensor. To do so, add
android:required="true"> to the application manifest.
For API details, see
Multiple cameras support
Applications can now make use of any cameras that are available on a device,
for either photo or video capture. The
applications query for the number of cameras available and the unique
characteristics of each.
Camera.CameraInfoclass stores a camera's positional characteristics (orientation, front-facing or back-facing).
getCameraInfo()methods in the
Cameraclass let applications query for the cameras available and open the camera that they need.
get()method lets applications retrieve a
CamcorderProfilefor a specific camera.
getJpegEncodingQualityParameter()lets applications obtain the still-image capture quality level for a specific camera.
To look at sample code for accessing a front-facing camera, see CameraPreview.java in the ApiDemos sample application.
The Camera API also adds:
- New parameters for cameras, including focus distance, focus mode, and
preview fps maximum/minimum. New
getSupportedPreviewFpsRange()for getting camera parameters, as well as
setPreviewFpsRange()for setting preview framerate.
Mixable audio effects
The platform's media framework adds support for new per-track or global audio effects, including bass boost, headphone virtualization, equalization, and reverb.
android.media.audiofxpackage provides the API to access audio effects.
AudioEffectis the base class for controlling audio effects provided by the Android audio framework.
- New audio session ID that lets an application associate a set of audio
effects with an instance of
AudioTrackclass constructor that lets you create an
AudioTrackwith a specific session ID. New
setAuxEffectSendLevel()methods and supporting types.
To look at sample code for audio effects, see AudioFxDemo.java in the ApiDemos sample application.
The media framework also adds:
- New support for altitude tag in EXIF metadata for JPEG files. New method
getAltitude()method to retrieve the value of the EXIF altitude tag.
setOrientationHint()method lets an application tell
MediaRecorderof the orientation during video capture.
The platform includes a new
DownloadManager system service
that handles long-running HTTP downloads. Applications can request that a URI be
downloaded to a particular destination file. The
will conduct the download in the background, taking care of HTTP interactions
and retrying downloads after failures or across connectivity changes and system
- Applications can obtain an instance of the
DownloadManagerclass by calling
DOWNLOAD_SERVICE. Applications that request downloads through this API should register a broadcast receiver for
ACTION_NOTIFICATION_CLICKED, to appropriately handle when the user clicks on a running download in a notification or from the Downloads UI.
DownloadManager.Requestclass lets an application provide all the information necessary to request a new download, such as request URI and download destination. A request URI is the only required parameter. Note that the default download destination is a shared volume where the system can delete your file if it needs to reclaim space for system use. For persistent storage of a download, specify a download destination on external storage (see
DownloadManager.Queryclass provides methods that let an application query for and filter active downloads.
To help developers monitor and improve the performance of their applications,
the platform offers a new system facility called
When implemented in an application, StrictMode catches and notifies the
developer of accidental disk or network activity that could degrade application
performance, such as activity taking place on the application's main thread
(where UI operations are received and animations are also taking place).
Developers can evaluate the network and disk usages issues raised in StrictMode
and correct them if needed, keeping the main thread more responsive and
preventing ANR dialogs from being shown to users.
StrictModeis the core class and is the main integration point with the system and VM. The class provides convenience methods for managing the thread and VM policies that apply to the instance.
StrictMode.VmPolicyhold the policies that you define and apply to thread and VM instances.
For more information about how to use StrictMode to optimize your
application, see the class documentation and sample code at
- Support for overscroll
- New support for overscroll in Views and Widgets. In Views, applications can enable/disable overscroll for a given view, set the overscoll mode, control the overscroll distance, and handle the results of overscrolling.
- In Widgets, applications can control overscroll characteristics such as
animation, springback, and overscroll distance. For more information, see
ViewConfigurationalso provides methods
<ListView>elements, for controlling overscroll behavior.
- Support for touch filtering
- New support for touch filtering, which lets an application improve the security of Views that provide access to sensitive functionality. For example, touch filtering is appropriate to ensure the security of user actions such as granting a permission request, making a purchase, or clicking on an advertisement. For details, see the View class documentation.
filterTouchesWhenObscuredattribute for view elements, which declares whether to filter touches when the view's window is obscured by another visible window. When set to
"true", the view will not receive touches whenever a toast, dialog or other window appears above the view's window. Refer to View security documentation for details.
To look at sample code for touch filtering, see SecureView.java in the ApiDemos sample application.
- Improved event management
- New base class for input events,
InputEvent. The class provides methods that let applications determine the meaning of the event, such as by querying for the InputDevice from which the event orginated. The
MotionEventare subclasses of
- New base class for input devices,
InputDevice. The class stores information about the capabilities of a particular input device and provides methods that let applications determine how to interpret events from an input device.
- New base class for input events,
- Improved motion events
MotionEventAPI is extended to include "pointer ID" information, which lets applications to keep track of individual fingers as they move up and down. The class adds a variety of methods that let an application work efficiently with motion events.
- The input system now has logic to generate motion events with the new pointer ID information, synthesizing identifiers as new pointers are down. The system tracks multiple pointer IDs separately during a motion event, and ensures proper continuity of pointers by evaluating at the distance between the last and next set of pointers.
- Text selection controls
- A new
setComposingRegionmethod lets an application mark a region of text as composing text, maintaining the current styling. A
getSelectedTextmethod returns the selected text to the application. The methods are available in
<TextView>, for referencing drawables that will be used to display text-selection anchors and the style for the containing window.
- A new
- Activity controls
ActivityInfoadds new constants for managing Activity orientation:
- New constant
ActivityManager.RunningAppProcessInfo. The value indicates that a specific process is running something that is considered to be actively perceptible to the user. An example would be an application performing background music playback.
- The Activity.setPersistent(boolean) method to mark an Activity as persistent is now deprecated and the implementation is a no-op.
- Notification text and icon styles
- Adds remaining OpenGL ES 2.0 methods
- Adds support for
YV12pixel format, a planar 4:2:0 YCrCb format.
AlarmClockprovider class for setting an alarm or handling an alarm. The provider contains a
ACTION_SET_ALARMIntent action and extras that can be used to start an Activity to set a new alarm in an alarm clock application. Applications that wish to receive the
SET_ALARMIntent should create an activity that requires the the SET_ALARM permission. Applications that wish to create a new alarm should use
Context.startActivity(), so that the user has the option of choosing which alarm clock application to use.
MediaStoresupports a new Intent action,
PLAY_FROM_SEARCH, that lets an application search for music media and automatically play content from the result when possible. For example, an application could fire this Intent as the result of a voice recognition command to listen to music.
MediaStorealso adds a new
MEDIA_IGNORE_FILENAMEflag that tells the media scanner to ignore media in the containing directory and its subdirectories. Developers can use this to avoid having graphics appear in the Gallery and likewise prevent application sounds and music from showing up in the Music app.
Settingsprovider adds the new Activity actions
MANAGE_ALL_APPLICATIONS_SETTINGS, which let an application show the details screen for a specific application or show the Manage Applications screen.
ContactsContractprovider adds the
ContactsContract.CommonDataKinds.SipAddressdata kind, for storing a contact's SIP (Internet telephony) address.
LocationManagernow tracks application requests that result in wake locks or wifi locks according to
WorkSource, a system-managed class that identifies the application.
LocationManagerkeeps track of all clients requesting periodic updates, and tells its providers about them as a
WorkSourceparameter, when setting their minimum update times. The network location provider uses
WorkSourceto track the wake and wifi locks initiated by an application and adds it to the application's battery usage reported in Manage Applications.
LocationManageradds several new methods that let an Activity register to receive periodic or one-time location updates based on specified criteria (see below).
- A new
Criteriaclass lets an application specify a set of criteria for selecting a location provider. For example, providers may be ordered according to accuracy, power usage, ability to report altitude, speed, and bearing, and monetary cost.
- Android 2.3 adds a new
StorageManagerthat supports OBB (Opaque Binary Blob) files. Although platform support for OBB is available in Android 2.3, development tools for creating and managing OBB files will not be availble until early 2011.
- The Android 2.3 platform adds official support for devices that do not
include SD cards (although it provides virtual SD Card partition, when no
physical SD card is available). A convenience method,
isExternalStorageRemovable(), lets applications determine whether a physical SD card is present.
- New constants for declaring hardware and software features. See the list in the New Feature Constants section, below.
lastUpdateTimefields that store the time of the package installation and last update.
getProviderInfo()method for retrieving all of the information known about a particular content provider class.
TelephonyManageradds the constant
NETWORK_TYPE_EVDO_Bfor specifying the CDMA EVDO Rev B network type.
getPsc()method returns the primary scrambling code of the serving cell on a UMTS network.
NativeActivityis a new type of Activity class, whose lifecycle callbacks are implemented directly in native code. A
NativeActivityand its underlying native code run in the system just as do other Activities — specifically they run in the Android application's system process and execute on the application's main UI thread, and they receive the same lifecycle callbacks as do other Activities.
InputQueueclass and callback interface lets native code manage event queueing.
SurfaceHolder.Callback2interface lets native code manage a
Windowlet native code manage events and surfaces.
dalvik.systemremoves several classes that were previously deprecated.
- Dalvik core libraries:
- New collections:
copyOfRange(), and others.
- More complete network APIs:
Fileread and write controls
- New collections:
<supports-screens>element, to indicate whether the application supports extra large screen form-factors. For details, see Supporting Multiple Screens.
- New values for
"reverseLandscape"— The Activity would like to have the screen in landscape orientation, turned in the opposite direction from normal landscape.
"reversePortrait"— The Activity would like to have the screen in portrait orientation, turned in the opposite direction from normal portrait.
"sensorLandscape"— The Activity would like to have the screen in landscape orientation, but can use the sensor to change which direction the screen is facing.
"sensorPortrait"— The Activity would like to have the screen in portrait orientation, but can use the sensor to change which direction the screen is facing.
"fullSensor"— Orientation is determined by a physical orientation sensor: the display will rotate based on how the user moves the device. This allows any of the 4 possible rotations, regardless of what the device will normally do (for example some devices won't normally use 180 degree rotation).
com.android.permission.SET_ALARM— Allows an application to broadcast an Intent to set an alarm for the user. An Activity that handles the
SET_ALARMIntent action should require this permission.
android.permission.USE_SIP— Allows an application to use the
SIP APIto make or receive internet calls.
android.permission.NFC— Allows an application to use the
NFC APIto read NFC tags.
android.hardware.audio.low_latency— The application uses a low-latency audio pipeline on the device and is sensitive to delays or lag in sound input or output.
android.hardware.camera.front— The application uses a front-facing camera on the device.
android.hardware.nfc— The application uses NFC radio features in the device.
android.hardware.sensor.barometer— The application uses the device's barometer.
android.hardware.sensor.gyroscope— The application uses the device's gyroscope sensor.
android.software.sip— The application uses the SIP API on the device.
android.software.sip.voip— The application uses a SIP-based VoIP service on the device.
android.hardware.touchscreen.multitouch.jazzhand— The application uses advanced multipoint multitouch capabilities on the device screen, for tracking five or more points fully independently.
Extra Large Screens
The platform now supports extra large screen sizes, such as those that might
be found on tablet devices. Developers can indicate that their applications are
designed to support extra large screen sizes by adding a
screens ... android:xlargeScreens="true"> element to their manifest
files. Applications can use a new resource qualifier,
tag resources that are specific to extra large screens. For
details on how to support extra large and other screen sizes, see Supporting Multiple
Native access to Activity lifecycle, windows
Android 2.3 exposes a broad set of APIs to applications that use native code. Framework classes of interest to such applications include:
For full information on working with native code or to download the NDK, see the Android NDK page.
New manifest elements and attributes
New Feature Constants
The platform adds several new hardware features that developers can declare in their application manifests as being required by their applications. This lets developers control how their application is filtered, when published on Google Play.
For full information about how to declare features and use them for
filtering, see the documentation for
API differences report
For a detailed view of all API changes in Android 2.3 (API Level 9), see the API Differences Report.
The Android 2.3 platform delivers an updated version of the framework API. The Android 2.3 API is assigned an integer identifier — 9 — 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 2.3 in your application,
you need compile the application against the Android library that is provided in
the Android 2.3 SDK platform. Depending on your needs, you might
also need to add an
attribute to the
<uses-sdk> element in the application's
manifest. If your application is designed to run only on Android 2.3 and higher,
declaring the attribute prevents the application from being installed on earlier
versions of the platform.
For more information, read What is API Level?