docs/html/guide/topics/manifest/uses-feature-element.jd

page.title=<uses-feature>
@jd:body

<dl class="xml">

<dt>syntax:</dt>
<dd>
<pre class="stx">
&lt;uses-feature android:<a href="#glEsVersion">glEsVersion</a>="<em>integer</em>"
              android:<a href="#name">name</a>="<em>string</em>"
              android:<a href="#required">required</a>=["true" | "false"] /&gt;
</pre>
</dd>

<dt>contained in:</dt>
<dd><code><a
href="{@docRoot}guide/topics/manifest/manifest-element.html">&lt;manifest&gt;</a></code></dd>

<dt>description:</dt>
<dd>This element declares a specific feature used by the application.
Android provides some features that may not be equally supported by all
Android devices. In a manner similar to the <code><a
href="uses-sdk-element.html">&lt;uses-sdk></a></code>
element, this element allows an application to specify which device-variable
features it uses. In this way, the application
will not be installed on devices that do not offer the feature.</p>

<p>For example, an application might specify that it requires a camera with auto-focus capabilities.
If a device does not provide a camera with auto-focus, then it will not allow
installation of the application.</p>

<p>In order to maintain strict device compatibility, it's very important that you use
this element to declare all applicable features (listed below) that your application uses. Failure
to declare a feature may result in your application being installed on a device
that does not support the feature and your application failing.</p>

<p>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
<a href="#glEsVersion">{@code glEsVersion}</a>). Other features that either do or do not
exist for a device, such as a camera, are declared using the
<a href="#name">{@code name}</a> attribute.</p>

<p>Any software or hardware features that may vary among Android-powered
devices will be listed on this page among the attributes below. If you see any features
here that you use in your application, you should include a {@code
&lt;uses-feature>} element for each one. For example, if your application uses the device
camera, then you should include the following in your {@code AndroidManifest.xml}:</p>

<pre>
&lt;uses-feature android:name="android.hardware.camera" />
</pre>

<p>If you declare {@code android.hardware.camera}, then your application is considered
compatible with all devices that include a camera. If your application also uses auto-focus
features, then you also need to include a
{@code &lt;uses-feature>} element that declares the {@code android.hardware.camera.autofocus}
feature. Also note that you must still request the {@link android.Manifest.permission#CAMERA
CAMERA} permission. Requesting permission grants your application access to the
appropriate hardware and software, while declaring the features used by
your application ensures proper device compatibility.</p>

<p>Although the {@code &lt;uses-feature>} element is only activated for devices running 
API Level 4 or higher, it is safe to include this for applications that declare 
a <a href="uses-sdk-element.html#min">{@code minSdkVersion}</a> 
of "3" or lower. Devices running older versions of the platform 
will simply ignore this element, but newer devices will recognize it and enforce 
installation restrictions based on whether the device supports the feature.</p>

<p class="note"><strong>Note:</strong>
For each feature required by your application, you must include a new {@code
&lt;uses-feature>} element. Multiple features cannot be declared in one 
instance of this element.</p>

</dd> 


<dt>attributes:</dt>

<dd>
<dl class="attr">
  <dt><a name="glEsVersion"></a>{@code android:glEsVersion}</dt>
  <dd>The GLES version needed by the application.
     The higher 16 bits represent the major number and the lower 16 bits
     represent the minor number. For example, for GL 1.2 referring to
     0x00000102, the actual value should be set as 0x00010002.
  </dd>

  <dt><a name="name"></a>{@code android:name}</dt>
  <dd>The name of a feature required by the application. 
  The value must be one of the following accepted strings:

  <table>
    <tr> 
       <th>Feature</th>
       <th>Value</th> 
       <th>Description</th> 
    </tr><tr>
       <td rowspan="2">Camera</td>
       <td>"{@code android.hardware.camera}"</td> 
       <td>The application requires a camera.</td> 
    </tr><tr>
       <td colspan="2">
         <strong>Note:</strong> Any application that requests the 
         {@link android.Manifest.permission#CAMERA} permission but does <em>not</em>
         declare any camera features with the {@code &lt;uses-feature>} element will be assumed
         to use all camera features (auto-focus and flash). Thus, the application will not
         be compatible with devices that do not support all camera features. Please use
         {@code &lt;uses-feature>} to declare only the camera features that your
         application does need. For instance, if you requests the
         {@link android.Manifest.permission#CAMERA} permission, but does not need auto-focus or
          flash, then declare only the {@code android.hardware.camera} feature&mdash;the camera
          features that you do not request will no longer be assumed as required.
       </td>
    </tr><tr>
      <td>Camera auto-focus</td>
      <td>"{@code android.hardware.camera.autofocus}"</td>
      <td>The application requires a camera with auto-focus capability.
       As a prerequisite, "{@code android.hardware.camera}" must also be declared
       with a separate {@code &lt;uses-feature>} element.
      </td>
    </tr>
  </table>
  </dd>

  <dt><a name="required"></a>{@code android:required}</dt>  <!-- added in api level 5 -->
  <dd>Indicates whether the feature is required by the application. This is
    "true" by default. <strong>You should not use this attribute for most cases.</strong>
    </p>

    <p>The only situation in which you should set this attribute "false" is when your application
    requests the {@link android.Manifest.permission#CAMERA} permission, but will degrade gracefully
    and perform without failure if the device does not have a camera. In this situation, you must
    declare the "{@code android.hardware.camera}" feature and set the {@code required} attribute
    "false". This is necessary because the {@link android.Manifest.permission#CAMERA} permission
    will automatically turn on the requirement for all camera features. So if your application uses
    this permission but is still compatible with devices without a camera, then you must set this
    attribute "false" for "{@code android.hardware.camera}" or else it will not install on devices
    without a camera. Note that, while the permission will enable the requirement for <em>all</em>
    camera features, you only need to off the requirement for the basic camera feature.</p>

  </dd>

</dl>
</dd>

<!-- ##api level indication## -->
<dt>introduced in:</dt>
<dd>API Level 4</dd>

<dt>see also:</dt>
<dd>
  <ul>
    <li>{@link android.content.pm.ConfigurationInfo}</li>
  </ul>
</dd>

</dl>