<uses-feature>

syntax:

<uses-feature android:name="string"
              android:required=["true" | "false"]
              android:glEsVersion="integer" />

contained in:

<manifest>

Android Market and <uses-feature> elements

Android Market filters the applications that are visible to users, so that users can see and download only those applications that are compatible with their devices. One of the ways Market filters applications is by feature compatibility.

To do this, Market checks the <uses-feature> elements in each application's manifest, to establish the app's feature needs. Market then shows or hides the application to each user, based on a comparison with the features available on the user's device.

By specifying the features that your application requires, you enable Android Market to present your application only to users whose devices meet the application's feature requirements, rather than presenting it to all users.

For important information about how Android Market uses features as the basis for filtering, please read Android Market and Feature-Based Filtering, below.

description:

Declares a single hardware or software feature that is used by the application.

The purpose of a <uses-feature> declaration is to inform any external entity of the set of hardware and software features on which your application depends. The element offers a required attribute that lets you specify whether your application requires and cannot function without the declared feature, or whether it prefers to have the feature but can function without it. Because feature support can vary across Android devices, the <uses-feature> element serves an important role in letting an application describe the device-variable features that it uses.

The set of available features that your application declares corresponds to the set of feature constants made available by the Android PackageManager, which are listed for convenience in the Features Reference tables at the bottom of this document.

You must specify each feature in a separate <uses-feature> element, so if your application requires multiple features, it would declare multiple <uses-feature> elements. For example, an application that requires both Bluetooth and camera features in the device would declare these two elements:

<uses-feature android:name="android.hardware.bluetooth" />
<uses-feature android:name="android.hardware.camera" />

In general, you should always make sure to declare <uses-feature> elements for all of the features that your application requires.

Declared <uses-feature> elements are informational only, meaning that the Android system itself does not check for matching feature support on the device before installing an application. However, other services (such as Android Market) or applications may check your application's <uses-feature> declarations as part of handling or interacting with your application. For this reason, it's very important that you declare all of the features (from the list below) that your application uses.

For some features, there may exist a specfic attribute that allows you to define a version of the feature, such as the version of Open GL used (declared with glEsVersion). Other features that either do or do not exist for a device, such as a camera, are declared using the name attribute.

Although the <uses-feature> element is only activated for devices running API Level 4 or higher, it is recommended to include these elements for all applications, even if the minSdkVersion is "3" or lower. Devices running older versions of the platform will simply ignore the element.

Note: When declaring a feature, remember that you must also request permissions as appropriate. For example, you must still request the CAMERA permission before your application can access the camera API. Requesting the permission grants your application access to the appropriate hardware and software, while declaring the features used by your application ensures proper device compatibility.

attributes:

android:name

Specifies a single hardware or software feature used by the application, as a descriptor string. Valid descriptor values are listed in the Hardware features and Software features tables, below.

android:required

Boolean value that indicates whether the application requires the feature specified in android:name.

When you declare "android:required="true" for a feature, you are specifying that the application cannot function, or is not designed to function, when the specified feature is not present on the device.
When you declare "android:required="false" for a feature, it means that the application prefers to use the feature if present on the device, but that it is designed to function without the specified feature, if necessary.

The default value for android:required if not declared is "true".

android:glEsVersion

The OpenGL ES version required by the application. The higher 16 bits represent the major number and the lower 16 bits represent the minor number. For example, to specify OpenGL ES version 2.0, you would set the value as "0x00020000". To specify OpenGL ES 2.1, if/when such a version were made available, you would set the value as "0x00020001".

An application should specify at most one android:glEsVersion attribute in its manifest. If it specifies more than one, the android:glEsVersion with the numerically highest value is used and any other values are ignored.

If an application does not specify an android:glEsVersion attribute, then it is assumed that the application requires only OpenGL ES 1.0, which is supported by all Android-powered devices.

An application can assume that if a platform supports a given OpenGL ES version, it also supports all numerically lower OpenGL ES versions. Therefore, an application that requires both OpenGL ES 1.0 and OpenGL ES 2.0 must specify that it requires OpenGL ES 2.0.

An application that can work with any of several OpenGL ES versions should only specify the numerically lowest version of OpenGL ES that it requires. (It can check at run-time whether a higher level of OpenGL ES is available.)

introduced in:

API Level 4

see also:

Android Market and Feature-Based Filtering

Android Market filters the applications that are visible to users, so that users can see and download only those applications that are compatible with their devices. One of the ways Market filters applications is by feature compatibility.

To determine an application's feature compatibility with a given user's device, the Android Market service compares:

Features required by the application — an application declares features in <uses-feature> elements in its manifest
with...
Features available on the device, in hardware or software — a device reports the features it supports as read-only system properties.

To ensure an accurate comparison of features, the Android Package Manager provides a shared set of feature constants that both applications and devices use to declare feature requirements and support. The available feature constants are listed in the Features Reference tables at the bottom of this document, and in the class documentation for PackageManager.

When the user launches the Market application, the application queries the Package Manager for the list of features available on the device by calling getSystemAvailableFeatures(). The Market application then passes the features list up to the Android Market service when establishing the session for the user.

Each time you upload an application to the Android Market Publisher Site, Android Market scans the application's manifest file. It looks for <uses-feature> elements and evaluates them in combination with other elements, in some cases, such as <uses-sdk> and <uses-permission> elements. After establishing the application's set of required features, it stores that list internally as metadata associated with the application .apk and the application version.

When a user searches or browses for applications using the Android Market application, the service compares the features needed by each application with the features available on the user's device. If all of an application's required features are present on the device, Android Market allows the user to see the application and potentially download it. If any required feature is not supported by the device, Android Market filters the application so that it is not visible to the user and not available for download.

Because the features you declare in <uses-feature> elements directly affect how Android Market filters your application, it's important to understand how Android Market evaluates the application's manifest and establishes the set of required features. The sections below provide more information.

Filtering based on explicitly declared features

An explicitly declared feature is one that your application declares in a <uses-feature> element. The feature declaration can include an android:required=["true" | "false"] attribute (if you are compiling against API level 5 or higher), which lets you specify whether the application absolutely requires the feature and cannot function properly without it ("true"), or whether the application prefers to use the feature if available, but is designed to run without it ("false").

Android Market handles explictly declared features in this way:

If a feature is explicitly declared as being required, Android Market adds the feature to the list of required features for the application. It then filters the application from users on devices that do not provide that feature. For example:
```
<uses-feature android:name="android.hardware.camera" android:required="true" />
```
If a feature is explicitly declared as not being required, Android Market does not add the feature to the list of required features. For that reason, an explicity declared non-required feature is never considered when filtering the application. Even if the device does not provide the declared feature, Android Market will still consider the application compatible with the device and will show it to the user, unless other filtering rules apply. For example:
```
<uses-feature android:name="android.hardware.camera" android:required="false" />
```
If a feature is explicitly declared, but without an android:required attribute, Android Market assumes that the feature is required and sets up filtering on it.

In general, if your application is designed to run on Android 1.6 and earlier versions, the android:required attribute is not available in the API and Android Market assumes that any and all <uses-feature> declarations are required.

Note: By declaring a feature explicitly and including an android:required="false" attribute, you can effectively disable all filtering on Android Market for the specified feature.

Filtering based on implicit features

An implicit feature is one that an application requires in order to function properly, but which is not declared in a <uses-feature> element in the manifest file. Strictly speaking, every application should always declare all features that it uses or requires, so the absence of a declaration for a feature used by an application should be considered an error. However, as a safeguard for users and developers, Android Market looks for implicit features in each application and sets up filters for those features, just as it would do for an explicitly declared feature.

An application might require a feature but not declare it because:

The application was compiled against an older version of the Android library (Android 1.5 or earlier) and the <uses-feature> element was not available.
The developer incorrectly assumed that the feature would be present on all devices and a declaration was unnecessary.
The developer omitted the feature declaration accidentally.
The developer declared the feature explicitly, but the declaration was not valid. For example, a spelling error in the <uses-feature> element name or an unrecognized string value for the android:name attribute would invalidate the feature declaration.

To account for the cases above, Android Market attempts to discover an application's implied feature requirements by examining other elements declared in the manifest file, specifically, <uses-permission> elements.

If an application requests hardware-related permissions, Android Market assumes that the application uses the underlying hardware features and therefore requires those features, even though there might be no corresponding to <uses-feature> declarations. For such permissions, Android Market adds the underlying hardware features to the metadata that it stores for the application and sets up filters for them.

For example, if an application requests the CAMERA permission but does not declare a <uses-feature> element for android.hardware.camera, Android Market considers that the application requires a camera and should not be shown to users whose devices do not offer a camera.

If you don't want Android Market to filter based on a specific implied feature, you can disable that behavior. To do so, declare the feature explicitly in a <uses-feature> element and include an android:required="false" attribute. For example, to disable filtering derived from the CAMERA permission, you would declare the feature as shown below.

<uses-feature android:name="android.hardware.camera" android:required="false" />

It's important to understand that the permissions that you request in <uses-permission> elements can directly affect how Android Market filters your application. The reference section Permissions that Imply Feature Requirements, below, lists the full set of permissions that imply feature requirements and therefore trigger filtering.

Special handling for Bluetooth feature

Android Market applies slightly different rules than described above, when determining filtering for Bluetooth.

If an application declares a Bluetooth permission in a <uses-permission> element, but does not explicitly declare the Bluetooth feature in a <uses-feature> element, Android Market checks the version(s) of the Android platform on which the application is designed to run, as specified in the <uses-sdk> element.

As shown in the table below, Android Market enables filtering for the Bluetooth feature only if the application declares its lowest or targeted platform as Android 2.0 (API level 5) or higher. However, note that Android market applies the normal rules for filtering when the application explicitly declares the Bluetooth feature in a <uses-feature> element.

Table 1. How Android Market determines the Bluetooth feature requirement for an application that requests a Bluetooth permission but does not declare the Bluetooth feature in a <uses-feature> element.

If `minSdkVersion` is ...	or `targetSdkVersion` is	Result
<=4 (or uses-sdk is not declared)	<=4	Android Market will not filter the application from any devices based on their reported support for the `android.hardware.bluetooth` feature.
<=4	>=5	Android Market filters the application from any devices that do not support the `android.hardware.bluetooth` feature (including older releases).
>=5	>=5

The examples below illustrate the different filtering effects, based on how Android Market handles the Bluetooth feature.

In first example, an application that is designed to run on older API levels declares a Bluetooth permission, but does not declare the Bluetooth feature in a <uses-feature> element.: Result: Android Market does not filter the application from any device.

<manifest ...>
...
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-sdk android:minSdkVersion="3" />
...
</manifest>

In the second example, below, the same application also declares a target API level of "5".: Result: Android Market now assumes that the feature is required and will filter the application from all devices that do not report Bluetooth support, including devices running older versions of the platform.

<manifest ...>
...
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-sdk android:minSdkVersion="3" android:targetSdkVersion="5" />
...
</manifest>

Here the same application now specifically declares the Bluetooth feature.: Result: Identical to the previous example (filtering is applied).

<manifest ...>
...
    <uses-feature android:name="android.hardware.bluetooth" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-sdk android:minSdkVersion="3" android:targetSdkVersion="5" />
...
</manifest>

Finally, in the case below, the same application adds an android:required="false" attribute.: Result: Android Market disables filtering based on Bluetooth feature support, for all devices.

<manifest ...>
...
    <uses-feature android:name="android.hardware.bluetooth" android:required="false" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-sdk android:minSdkVersion="3" android:targetSdkVersion="5" />
...
</manifest>

Testing the features required by your application

You can use the aapt tool, included in the Android SDK, to determine how Android Market will filter your application, based on its declared features and permissions. To do so, run aapt with the dump badging command. This causes aapt to parse your application's manifest and apply the same rules as used by Android Market to determine the features that your application requires.

To use the tool, follow these steps:

First, build and export your application as an unsigned .apk. If you are developing in Eclipse with ADT, right-click the project and select Android Tools > Export Unsigned Application Package. Select a destination filename and path and click OK.
Next, locate the aapt tool, if it is not already in your PATH. If you are using SDK Tools r8 or higher, you can find aapt in the <SDK>/platform-tools/ directory.
Note: You must use the version of aapt that is provided for the latest Platform-Tools component available. If you do not have the latest Platform-Tools component, download it using the Android SDK and AVD Manager.
Run aapt using this syntax:

$ aapt dump badging <path_to_exported_.apk>

Here's an example of the command output for the second Bluetooth example, above:

$ ./aapt dump badging BTExample.apk
package: name='com.example.android.btexample' versionCode='' versionName=''
uses-permission:'android.permission.BLUETOOTH_ADMIN'
uses-feature:'android.hardware.bluetooth'
sdkVersion:'3'
targetSdkVersion:'5'
application: label='BT Example' icon='res/drawable/app_bt_ex.png'
launchable activity name='com.example.android.btexample.MyActivity'label='' icon=''
uses-feature:'android.hardware.touchscreen'
main
supports-screens: 'small' 'normal' 'large'
locales: '--_--'
densities: '160'

Features Reference

The tables below provide reference information about hardware and software features and the permissions that can imply them on Android Market.

Hardware features

The table below describes the hardware feature descriptors supported by the most current platform release. To signal that your application uses or requires a hardware feature, declare each value in a android:name attribute in a separate <uses-feature> element.

Feature Type	Feature Descriptor	Description	Comments
Audio	`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.
Bluetooth	`android.hardware.bluetooth`	The application uses Bluetooth radio features in the device.
Camera	`android.hardware.camera`	The application uses the device's camera. If the device supports multiple cameras, the application uses the camera that facing away from the screen.
	`android.hardware.camera.autofocus`	Subfeature. The application uses the device camera's autofocus capability.	If declared with the `"android:required="true"` attribute, these subfeatures implicitly declare the `android.hardware.camera` parent feature.
	`android.hardware.camera.flash`	Subfeature. The application uses the device camera's flash.
	`android.hardware.camera.front`	Subfeature. The application uses a front-facing camera on the device.
Location	`android.hardware.location`	The application uses one or more features on the device for determining location, such as GPS location, network location, or cell location.
	`android.hardware.location.network`	Subfeature. The application uses coarse location coordinates obtained from a network-based geolocation system supported on the device.	If declared with the `"android:required="true"` attribute, these subfeatures implicitly declare the `android.hardware.location` parent feature.
	`android.hardware.location.gps`	Subfeature. The application uses precise location coordinates obtained from a Global Positioning System receiver on the device.
Microphone	`android.hardware.microphone`	The application uses a microphone on the device.
Near Field Communications	`android.hardware.nfc`	The application uses NFC radio features in the device.
Sensors	`android.hardware.sensor.accelerometer`	The application uses motion readings from an accelerometer on the device.
	`android.hardware.sensor.barometer`	The application uses the device's barometer.
	`android.hardware.sensor.compass`	The application uses directional readings from a magnetometer (compass) on the device.
	`android.hardware.sensor.gyroscope`	The application uses the device's gyroscope sensor.
	`android.hardware.sensor.light`	The application uses the device's light sensor.
	`android.hardware.sensor.proximity`	The application uses the device's proximity sensor.
Telephony	`android.hardware.telephony`	The application uses telephony features on the device, such as telephony radio with data communication services.
	`android.hardware.telephony.cdma`	Subfeature. The application uses CDMA telephony radio features on the device.	If declared with the `"android:required="true"` attribute, these subfeatures implicitly declare the `android.hardware.telephony` parent feature.
	`android.hardware.telephony.gsm`	Subfeature. The application uses GSM telephony radio features on the device.
Touchscreen	`android.hardware.touchscreen`	The application uses touchscreen capabilities on the device.
	`android.hardware.touchscreen.multitouch`	Subfeature. The application uses basic two-point multitouch capabilities on the device screen.	If declared with the `"android:required="true"` attribute, this subfeature implicitly declares the `android.hardware.touchscreen` parent feature.
	`android.hardware.touchscreen.multitouch.distinct`	Subfeature. The application uses advanced multipoint multitouch capabilities on the device screen, such as for tracking two or more points fully independently.	If declared with the `"android:required="true"` attribute, this subfeature implicitly declares the `android.hardware.touchscreen.multitouch` parent feature.
	`android.hardware.touchscreen.multitouch.jazzhand`	Subfeature. The application uses advanced multipoint multitouch capabilities on the device screen, for tracking up to five points fully independently.
Wifi	`android.hardware.wifi`	The application uses 802.11 networking (wifi) features on the device.

Software features

The table below describes the software feature descriptors supported by the most current platform release. To signal that your application uses or requires a software feature, declare each value in a android:name attribute in a separate <uses-feature> element.

Feature	Attribute Value	Description	Comments
Live Wallpaper	`android.software.live_wallpaper`	The application uses or provides Live Wallpapers.
SIP/VOIP	`android.software.sip`	The application uses SIP service on the device.
SIP/VOIP	`android.software.sip.voip`	Subfeature. The application uses SIP-based VOIP service on the device.	If declared with the `"android:required="true"` attribute, this subfeature implicitly declares the `android.software.sip` parent feature.

Permissions that Imply Feature Requirements

Some feature constants listed in the tables above were made available to applications after the corresponding API; for example, the android.hardware.bluetooth feature was added in Android 2.2 (API level 8), but the bluetooth API that it refers to was added in Android 2.0 (API level 5). Because of this, some apps were able to use the API before they had the ability to declare that they require the API via the <uses-feature> system.

To prevent those apps from being made available unintentionally, Android Market assumes that certain hardware-related permissions indicate that the underlying hardware features are required by default. For instance, applications that use Bluetooth must request the BLUETOOTH permission in a <uses-permission> element — for legacy apps, Android Market assumes that the permission declaration means that the underlying android.hardware.bluetooth feature is required by the application and sets up filtering based on that feature.

The table below lists permissions that imply feature requirements equivalent to those declared in <uses-feature> elements. Note that <uses-feature> declarations, including any declared android:required attribute, always take precedence over features implied by the permissions below.

For any of the permissions below, you can disable filtering based on the implied feature by explicitly declaring the implied feature explicitly, in a <uses-feature> element, with an android:required="false" attribute. For example, to disable any filtering based on the CAMERA permission, you would add this <uses-feature> declaration to the manifest file:

<uses-feature android:name="android.hardware.camera" android:required="false" />

Category	This Permission...	Implies This Feature Requirement
Bluetooth	`BLUETOOTH`	`android.hardware.bluetooth` (See Special handling for Bluetooth feature for details.)
Bluetooth	`BLUETOOTH_ADMIN`	`android.hardware.bluetooth`
Camera	`CAMERA`	`android.hardware.camera` and `android.hardware.camera.autofocus`
Location	`ACCESS_MOCK_LOCATION`	`android.hardware.location`
	`ACCESS_LOCATION_EXTRA_COMMANDS`	`android.hardware.location`
	`INSTALL_LOCATION_PROVIDER`	`android.hardware.location`
	`ACCESS_COARSE_LOCATION`	`android.hardware.location.network` and `android.hardware.location`
	`ACCESS_FINE_LOCATION`	`android.hardware.location.gps` and `android.hardware.location`
Microphone	`RECORD_AUDIO`	`android.hardware.microphone`
Telephony	`CALL_PHONE`	`android.hardware.telephony`
	`CALL_PRIVILEGED`	`android.hardware.telephony`
	`MODIFY_PHONE_STATE`	`android.hardware.telephony`
	`PROCESS_OUTGOING_CALLS`	`android.hardware.telephony`
	`READ_SMS`	`android.hardware.telephony`
	`RECEIVE_SMS`	`android.hardware.telephony`
	`RECEIVE_MMS`	`android.hardware.telephony`
	`RECEIVE_WAP_PUSH`	`android.hardware.telephony`
	`SEND_SMS`	`android.hardware.telephony`
	`WRITE_APN_SETTINGS`	`android.hardware.telephony`
	`WRITE_SMS`	`android.hardware.telephony`
Wifi	`ACCESS_WIFI_STATE`	`android.hardware.wifi`
	`CHANGE_WIFI_STATE`	`android.hardware.wifi`
	`CHANGE_WIFI_MULTICAST_STATE`	`android.hardware.wifi`

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Best Practices Bewährte Verfahren Prácticas recomendadas Meilleures pratiques Best practice ベストプラクティス最佳实践最佳實務

Web Applications

Appendix Anhang Apéndice Annexes Appendice 付録附录附錄

<uses-feature>

Android Market and Feature-Based Filtering

Filtering based on explicitly declared features

Filtering based on implicit features

Special handling for Bluetooth feature

Testing the features required by your application

Features Reference

Hardware features

Software features

Permissions that Imply Feature Requirements

Android Basics Einführung in Android Información básica sobre Android Présentation d'Android Nozioni di base su Android Android の基本 Android 基础知识 Android 簡介

Framework Topics Framework-Themen Temas sobre el framework Thèmes relatifs au framework Argomenti relativi al framework フレームワーク トピック 框架主题 架構主題

Developing Entwicklung Desarrollo Développement Sviluppo 開発 开发 開發

Publishing Veröffentlichung Publicación Publication Pubblicazione 公開 发布 發佈

Best Practices Bewährte Verfahren Prácticas recomendadas Meilleures pratiques Best practice ベスト プラクティス 最佳实践 最佳實務

Web Applications

Appendix Anhang Apéndice Annexes Appendice 付録 附录 附錄

<uses-feature>

Android Market and Feature-Based Filtering

Filtering based on explicitly declared features

Filtering based on implicit features

Special handling for Bluetooth feature

Testing the features required by your application

Features Reference

Hardware features

Software features

Permissions that Imply Feature Requirements

Framework Topics Framework-Themen Temas sobre el framework Thèmes relatifs au framework Argomenti relativi al framework フレームワークトピック框架主题架構主題

Developing Entwicklung Desarrollo Développement Sviluppo 開発开发開發

Publishing Veröffentlichung Publicación Publication Pubblicazione 公開发布發佈

Best Practices Bewährte Verfahren Prácticas recomendadas Meilleures pratiques Best practice ベストプラクティス最佳实践最佳實務

Appendix Anhang Apéndice Annexes Appendice 付録附录附錄