API Level: 10
Android 2.3.3 (GINGERBREAD_MR1
)
is a small feature release that adds several improvements
and APIs to the Android 2.3 platform.
For developers, the Android 2.3.3 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 2.3.3, use the Android SDK Manager to download the platform into your SDK.
API Overview
The sections below provide a technical overview of what's new for developers in 2.3.3, including new features and changes in the framework API since the previous version.
Near Field Communications (NFC)
Android 2.3.3 provides improved and extended support for NFC, to allow applications to interact with more types of tags in new ways.
A new, comprehensive set of APIs give applications read and write access to a wider range of standard tag technologies, including:
- NFC-A (ISO 14443-3A)
- NFC-B (ISO 14443-3B)
- NFC-F (JIS 6319-4)
- NFC-V (ISO 15693)
- ISO-DEP (ISO 14443-4)
- MIFARE Classic
- MIFARE Ultralight
- NFC Forum NDEF tags
The platform also provides a limited peer-to-peer communication protocol and API. Foreground Activities can use the API to register an NDEF message that will get pushed to other NFC devices when they connect.
Advanced tag dispatching now gives applications more control over how and
when they are launched, when an NFC tag is discovered. Previously, the platform
used a single-step intent dispatch to notify interested applications that a tag
was discovered. The platform now uses a four-step process that enables the
foreground application to take control of a tag event before it is passed to any
other applications (android.nfc.NfcAdapter.enableForegroundDispatch()
).
The new dispatch process also lets apps listen for specific tag content and
tag technologies, based on two new intent actions —
android.nfc.action.NDEF_DISCOVERED
and
android.nfc.action.TECH_DISCOVERED
.
The NFC API is available in the android.nfc
and
android.nfc.tech
packages. 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. An NDEF message certain many NDEF records of different types. Applications can receive these messages fromNDEF_DISCOVERED
,TECH_DISCOVERED
, orTAG_DISCOVERED
Intents.NdefRecord
, delivered in anNdefMessage
, which describes the type of data being shared and carries the data itself.Tag
, which represents a tag scanned by the device. Multiple types of tags are supported, based on the underlying tag technology.TagTechnology
, an interface that gives applications access to tag properties and I/O operations based on the technologies present in the tag. For a full list of tag technologies supported in Android 2.3.3, seeandroid.nfc.tech
.
NFC communication relies on wireless technology in the device hardware, and
is not present in all Android devices. Android devices that do not support
NFC will return a null object when
getDefaultAdapter(Context)
is called, and
context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_NFC)
will return false
. 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
declaring <uses-permission
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
<uses-feature android:name="android.hardware.nfc"
android:required="true">
to the application's manifest.
For more information, read the NFC developer guide.
Bluetooth
Android 2.3.3 adds platform and API support for Bluetooth nonsecure socket
connections. This lets applications communicate with simple devices that may not
offer a UI for authentication. See
createInsecureRfcommSocketToServiceRecord(java.util.UUID)
and
listenUsingInsecureRfcommWithServiceRecord(java.lang.String, java.util.UUID)
for more information.
Graphics
- A new
BitmapRegionDecoder
class lets applications decode a rectangle region from an image. The API is particularly useful when an original image is large and and the application only need parts of the image. - A new
inPreferQualityOverSpeed
field inBitmapFactory.Options
allows applications to use a more accurate but slightly slower IDCT method in JPEG decode. This in turn improves the quality of the reconstructed image.
Media framework
- A new
MediaMetadataRetriever
class provides a unified interface for retrieving frame and metadata from an input media file. MediaRecorder.AudioEncoder
andMediaRecorder.OutputFormat
include new fields for specifying AMR Wideband and AAC formats.
Speech recognition
The speech-recognition API includes new constants to let you manage voice
search results in new ways. Although the new constants are not needed for normal
use of speech recognition, you could use them to offer a different view of voice
search results in your application. For information, see RecognizerResultsIntent
.
API Level
The Android 2.3.3 platform delivers an updated version of the framework API. The Android 2.3.3 API is assigned an integer identifier — 10 — 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 2.3.3 in your application,
you need compile the application against the Android library that is provided in
the Android 2.3.3 SDK platform. Depending on your needs, you might
also need to add an android:minSdkVersion="10"
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?