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      1 page.title=<uses-sdk>
      2 parent.title=The AndroidManifest.xml File
      3 parent.link=manifest-intro.html
      4 @jd:body
      5 
      6 
      7 <div id="qv-wrapper">
      8 <div id="qv">
      9 
     10 <h2>In this document</h2>
     11 <ol>
     12   <li><a href="#ApiLevels">What is API Level?</a></li>
     13   <li><a href="#uses">Uses of API Level in Android</a></li>
     14   <li><a href="#considerations">Development Considerations</a>
     15     <ol>
     16       <li><a href="#fc">Application forward compatibility</a></li>
     17       <li><a href="#bc">Application backward compatibility</a></li>
     18       <li><a href="#platform">Selecting a platform version and API Level</a></li>
     19       <li><a href="#apilevel">Declaring a minimum API Level</a></li>
     20       <li><a href="#testing">Testing against higher API Levels</a></li>
     21     </ol>
     22   </li>
     23   <li><a href="#provisional">Using a Provisional API Level</a></li>
     24   <li><a href="#filtering">Filtering the Reference Documentation by API Level</a></li>
     25 </ol>
     26 </div>
     27 </div>
     28 
     29 <dl class="xml">
     30 <dt>syntax:</dt>
     31 <dd><pre>
     32 &lt;uses-sdk android:<a href="#min">minSdkVersion</a>="<i>integer</i>" 
     33           android:<a href="#target">targetSdkVersion</a>="<i>integer</i>"
     34           android:<a href="#max">maxSdkVersion</a>="<i>integer</i>" /&gt;</pre></dd>
     35 
     36 <dt>contained in:</dt>
     37 <dd><code><a href="{@docRoot}guide/topics/manifest/manifest-element.html">&lt;manifest&gt;</a></code></dd>
     38 
     39 <dt>description:</dt>
     40 <dd>Lets you express an application's compatibility with one or more versions of the Android platform,
     41 by means of an API Level integer. The API Level expressed by an application will be compared to the
     42 API Level of a given Android system, which may vary among different Android devices.
     43 </p>
     44 
     45 <p>Despite its name, this element is used to specify the API Level, <em>not</em>
     46 the version number of the SDK (software development kit) or Android platform. 
     47 The API Level is always a single integer. You cannot derive the API Level from
     48 its associated Android version number (for example, it is not the same as the
     49 major version or the sum of the major and minor versions).</p>
     50 
     51 <p>Also read the document about
     52 <a href="{@docRoot}tools/publishing/versioning.html">Versioning Your Applications</a>.
     53 </p></dd> 
     54 
     55  <div class="sidebox-wrapper" xstyle="margin-bottom:2em;margin-top:.5em;width:90%;"> 
     56   <img id="rule" src="{@docRoot}assets/images/grad-rule-qv.png"> 
     57   <div id="qv-sub-rule"> 
     58     <img src="{@docRoot}assets/images/icon_play.png" style="float:left;margin:0;padding:0;"> 
     59     <p style="color:#669999;padding-top:1em;">Google Play and &lt;uses-sdk&gt; attributes</p> 
     60     <p style="padding-top:1em;">Google Play filters the applications that are visible to users, so
     61 that users can only see and download applications that are compatible with their
     62 devices. One of the ways it filters applications is by Android
     63 version-compatibility. To do this, Google Play checks the <code>&lt;uses-sdk&gt;</code>
     64 attributes in each application's manifest to establish its version-compatibility
     65 range, then shows or hides the application based on a comparison with the API
     66 Level of the user's Android system version. For more information, see <a
     67 href="{@docRoot}guide/google/play/filters.html">Filters on Google Play</a>.</p>
     68   </div>
     69 </div>
     70 
     71 <dt>attributes:</dt>
     72 
     73 <dd>
     74 <dl class="attr">
     75   <dt><a name="min"></a>{@code android:minSdkVersion}</dt>
     76   <dd>An integer designating the minimum API Level required
     77   for the application to run. The Android system will prevent the user from installing
     78   the application if the system's API Level is lower than the value specified in
     79   this attribute. You should always declare this attribute.
     80 
     81   <p class="caution"><strong>Caution:</strong> If you do not declare this
     82   attribute, the system assumes a default value of "1", which indicates that your
     83   application is compatible with all versions of Android. If your application is
     84   <em>not</em> compatible with all versions (for instance, it uses APIs introduced
     85   in API Level 3) and you have not declared the proper <code>minSdkVersion</code>,
     86   then when installed on a system with an API Level less than 3, the application
     87   will crash during runtime when attempting to access the unavailable APIs. For
     88   this reason, be certain to declare the appropriate API Level in the
     89   <code>minSdkVersion</code> attribute.</p>
     90   </dd>
     91 
     92   <dt><a name="target"></a>{@code android:targetSdkVersion}</dt>
     93   <dd>An integer designating the API Level that the application targets. If not set, the default
     94 value equals that given to {@code minSdkVersion}.
     95 
     96   <p>This attribute informs the system that you have tested against the target version and the
     97 system should not enable any compatibility behaviors to maintain your app's forward-compatibility
     98 with the target version. The application is still able to run on older versions (down to {@code
     99 minSdkVersion}).</p>
    100 
    101   <p>As Android evolves with each new version, some behaviors and even appearances might change.
    102 However, if the API level of the platform is higher than the version declared by your app's {@code
    103 targetSdkVersion}, the system may enable compatibility behaviors to ensure that your app
    104 continues to work the way you expect. You can disable such compatibility
    105 behaviors by specifying {@code targetSdkVersion} to match the API
    106 level of the platform on which it's running. For example, setting this value to "11" or higher
    107 allows the system to apply a new default theme (Holo) to your app when running on Android 3.0 or
    108 higher and also disables <a href="{@docRoot}guide/practices/screen-compat-mode.html">screen
    109 compatibility mode</a> when running on larger screens (because support for API level 11 implicitly
    110 supports larger screens).</p>
    111 
    112   <p>There are many compatibility behaviors that the system may enable based on the value you set
    113 for this attribute. Several of these behaviors are described by the corresponding platform versions
    114 in the {@link android.os.Build.VERSION_CODES} reference.</p>
    115 
    116   <p>To maintain your application along with each Android release, you should increase
    117 the value of this attribute to match the latest API level, then thoroughly test your application on
    118 the corresponding platform version.</p>
    119 
    120   <p>Introduced in: API Level 4</p>
    121   </dd>
    122 
    123   <dt><a name="max"></a>{@code android:maxSdkVersion}</dt>
    124   <dd>An integer designating the maximum API Level on which the application is 
    125   designed to run. 
    126 
    127   <p>In Android 1.5, 1.6, 2.0, and 2.0.1, the system checks the value of this
    128   attribute when installing an application and when re-validating the application
    129   after a system update. In either case, if the application's
    130   <code>maxSdkVersion</code> attribute is lower than the API Level used by
    131   the system itself, then the system will not allow the application to be
    132   installed. In the case of re-validation after system update, this effectively
    133   removes your application from the device.
    134 
    135   <p>To illustrate how this attribute can affect your application after system
    136   updates, consider the following example: </p>
    137 
    138   <p>An application declaring <code>maxSdkVersion="5"</code> in its
    139   manifest is published on Google Play. A user whose device is running Android
    140   1.6 (API Level 4) downloads and installs the app. After a few weeks, the user
    141   receives an over-the-air system update to Android 2.0 (API Level 5). After the
    142   update is installed, the system checks the application's
    143   <code>maxSdkVersion</code> and successfully re-validates it. The
    144   application functions as normal. However, some time later, the device receives
    145   another system update, this time to Android 2.0.1 (API Level 6). After the
    146   update, the system can no longer re-validate the application because the system's
    147   own API Level (6) is now higher than the maximum supported by the application
    148   (5). The system prevents the application from being visible to the user, in
    149   effect removing it from the device.</p>
    150 
    151   <p class="warning"><strong>Warning:</strong> Declaring this attribute is not
    152   recommended. First, there is no need to set the attribute as means of blocking
    153   deployment of your application onto new versions of the Android platform as they
    154   are released. By design, new versions of the platform are fully
    155   backward-compatible. Your application should work properly on new versions,
    156   provided it uses only standard APIs and follows development best practices.
    157   Second, note that in some cases, declaring the attribute can <strong>result in
    158   your application being removed from users' devices after a system
    159   update</strong> to a higher API Level. Most devices on which your application
    160   is likely to be installed will receive periodic system updates over the air, so
    161   you should consider their effect on your application before setting this
    162   attribute.</p>
    163 
    164   <p style="margin-bottom:1em;">Introduced in: API Level 4</p>
    165 
    166   <div class="special">Future versions of Android (beyond Android 2.0.1) will no
    167 longer check or enforce the <code>maxSdkVersion</code> attribute during
    168 installation or re-validation. Google Play will continue to use the attribute
    169 as a filter, however, when presenting users with applications available for
    170 download. </div>
    171   </dd>
    172   
    173 
    174 </dl></dd>
    175 
    176 <!-- ##api level indication## -->
    177 <dt>introduced in:</dt>
    178 <dd>API Level 1</dd>
    179 
    180 </dl>
    181 
    182 
    183 
    184 
    185 
    186 <!--- CONTENT FROM OLD API LEVEL DOC ---->
    187 
    188 
    189 
    190 
    191 <h2 id="ApiLevels">What is API Level?</h2>
    192 
    193 <p>API Level is an integer value that uniquely identifies the framework API
    194 revision offered by a version of the Android platform.</p>
    195 
    196 <p>The Android platform provides a framework API that applications can use to
    197 interact with the underlying Android system. The framework API consists of:</p>
    198 
    199 <ul>
    200 <li>A core set of packages and classes</li>
    201 <li>A set of XML elements and attributes for declaring a manifest file</li>
    202 <li>A set of XML elements and attributes for declaring and accessing resources</li>
    203 <li>A set of Intents</li>
    204 <li>A set of permissions that applications can request, as well as permission
    205 enforcements included in the system</li>
    206 </ul>
    207 
    208 <p>Each successive version of the Android platform can include updates to the
    209 Android application framework API that it delivers. </p>
    210 
    211 <p>Updates to the framework API are designed so that the new API remains
    212 compatible with earlier versions of the API. That is, most changes in the API
    213 are additive and introduce new or replacement functionality. As parts of the API
    214 are upgraded, the older replaced parts are deprecated but are not removed, so
    215 that existing applications can still use them. In a very small number of cases,
    216 parts of the API may be modified or removed, although typically such changes are
    217 only needed to ensure API robustness and application or system security. All
    218 other API parts from earlier revisions are carried forward without
    219 modification.</p>
    220 
    221 <p>The framework API that an Android platform delivers is specified using an
    222 integer identifier called "API Level". Each Android platform version supports
    223 exactly one API Level, although support is implicit for all earlier API Levels
    224 (down to API Level 1). The initial release of the Android platform provided 
    225 API Level 1 and subsequent releases have incremented the API Level.</p>
    226 
    227 <p>The following table specifies the API Level supported by each version of the
    228 Android platform.</p>
    229 
    230 <table>
    231   <tr><th>Platform Version</th><th>API Level</th><th>VERSION_CODE</th><th>Notes</th></tr>
    232  
    233     <tr><td><a href="{@docRoot}about/versions/android-4.1.html">Android 4.1, 4.1.1</a></td>
    234     <td><a href="{@docRoot}sdk/api_diff/16/changes.html" title="Diff Report">16</a></td>
    235     <td>{@link android.os.Build.VERSION_CODES#JELLY_BEAN}</td>
    236     <td><a href="{@docRoot}about/versions/jelly-bean.html">Platform
    237 Highlights</a></td></tr>
    238 
    239     <tr><td><a href="{@docRoot}about/versions/android-4.0.3.html">Android 4.0.3, 4.0.4</a></td>
    240     <td><a href="{@docRoot}sdk/api_diff/15/changes.html" title="Diff Report">15</a></td>
    241     <td>{@link android.os.Build.VERSION_CODES#ICE_CREAM_SANDWICH_MR1}</td>
    242     <td rowspan="2"><a href="{@docRoot}about/versions/android-4.0-highlights.html">Platform
    243 Highlights</a></td></tr>
    244 
    245     <tr><td><a href="{@docRoot}about/versions/android-4.0.html">Android 4.0, 4.0.1, 4.0.2</a></td>
    246     <td><a href="{@docRoot}sdk/api_diff/14/changes.html" title="Diff Report">14</a></td>
    247     <td>{@link android.os.Build.VERSION_CODES#ICE_CREAM_SANDWICH}</td>
    248     </tr>
    249   
    250     <tr><td><a href="{@docRoot}about/versions/android-3.2.html">Android 3.2</a></td>
    251     <td><a href="{@docRoot}sdk/api_diff/13/changes.html" title="Diff Report">13</a></td>
    252     <td>{@link android.os.Build.VERSION_CODES#HONEYCOMB_MR2}</td>
    253     <td><!-- <a href="{@docRoot}about/versions/android-3.2-highlights.html">Platform
    254 Highlights</a>--></td></tr>
    255   
    256   <tr><td><a href="{@docRoot}about/versions/android-3.1.html">Android 3.1.x</a></td>
    257     <td><a href="{@docRoot}sdk/api_diff/12/changes.html" title="Diff Report">12</a></td>
    258     <td>{@link android.os.Build.VERSION_CODES#HONEYCOMB_MR1}</td>
    259     <td><a href="{@docRoot}about/versions/android-3.1-highlights.html">Platform Highlights</a></td></tr>
    260     
    261   <tr><td><a href="{@docRoot}about/versions/android-3.0.html">Android 3.0.x</td>
    262     <td><a href="{@docRoot}sdk/api_diff/11/changes.html" title="Diff Report">11</a></td>
    263     <td>{@link android.os.Build.VERSION_CODES#HONEYCOMB}</td>
    264     <td><a href="{@docRoot}about/versions/android-3.0-highlights.html">Platform Highlights</a></td></tr>
    265     
    266   <tr><td><a href="{@docRoot}about/versions/android-2.3.3.html">Android 2.3.4<br>Android 2.3.3</td>
    267     <td><a href="{@docRoot}sdk/api_diff/10/changes.html" title="Diff Report">10</a></td>
    268     <td>{@link android.os.Build.VERSION_CODES#GINGERBREAD_MR1}</td>
    269     <td rowspan="2"><a href="{@docRoot}about/versions/android-2.3-highlights.html">Platform
    270 Highlights</a></td></tr>
    271   
    272   <tr><td><a href="{@docRoot}about/versions/android-2.3.html">Android 2.3.2<br>Android 2.3.1<br>Android
    273 2.3</td>
    274     <td><a href="{@docRoot}sdk/api_diff/9/changes.html" title="Diff Report">9</a></td>
    275     <td>{@link android.os.Build.VERSION_CODES#GINGERBREAD}</td>
    276     </tr>
    277   
    278   <tr><td><a href="{@docRoot}about/versions/android-2.2.html">Android 2.2.x</td>
    279     <td ><a href="{@docRoot}sdk/api_diff/8/changes.html" title="Diff Report">8</a></td>
    280     <td>{@link android.os.Build.VERSION_CODES#FROYO}</td>
    281     <td><a href="{@docRoot}about/versions/android-2.2-highlights.html">Platform Highlights</a></td></tr>
    282   
    283   <tr><td><a href="{@docRoot}about/versions/android-2.1.html">Android 2.1.x</td>
    284     <td><a href="{@docRoot}sdk/api_diff/7/changes.html" title="Diff Report">7</a></td>
    285     <td>{@link android.os.Build.VERSION_CODES#ECLAIR_MR1}</td>
    286     <td rowspan="3" ><a href="{@docRoot}about/versions/android-2.0-highlights.html">Platform
    287 Highlights</a></td></tr>
    288     
    289   <tr><td><a href="{@docRoot}about/versions/android-2.0.1.html">Android 2.0.1</td>
    290     <td><a href="{@docRoot}sdk/api_diff/6/changes.html" title="Diff Report">6</a></td>
    291     <td>{@link android.os.Build.VERSION_CODES#ECLAIR_0_1}</td>
    292     </tr>
    293     
    294   <tr><td><a href="{@docRoot}about/versions/android-2.0.html">Android 2.0</td>
    295     <td><a href="{@docRoot}sdk/api_diff/5/changes.html" title="Diff Report">5</a></td>
    296     <td>{@link android.os.Build.VERSION_CODES#ECLAIR}</td>
    297     </tr>
    298     
    299   <tr><td><a href="{@docRoot}about/versions/android-1.6.html">Android 1.6</td>
    300     <td><a href="{@docRoot}sdk/api_diff/4/changes.html" title="Diff Report">4</a></td>
    301     <td>{@link android.os.Build.VERSION_CODES#DONUT}</td>
    302     <td><a href="{@docRoot}about/versions/android-1.6-highlights.html">Platform Highlights</a></td></tr>
    303     
    304   <tr><td><a href="{@docRoot}about/versions/android-1.5.html">Android 1.5</td>
    305     <td><a href="{@docRoot}sdk/api_diff/3/changes.html" title="Diff Report">3</a></td>
    306     <td>{@link android.os.Build.VERSION_CODES#CUPCAKE}</td>
    307     <td><a href="{@docRoot}about/versions/android-1.5-highlights.html">Platform Highlights</a></td></tr>
    308     
    309   <tr><td><a href="{@docRoot}about/versions/android-1.1.html">Android 1.1</td>
    310     <td>2</td>
    311     <td>{@link android.os.Build.VERSION_CODES#BASE_1_1}</td><td></td></tr>
    312     
    313   <tr><td>Android 1.0</td>
    314     <td>1</td>
    315     <td>{@link android.os.Build.VERSION_CODES#BASE}</td>
    316     <td></td></tr>
    317 </table>
    318 
    319 
    320 <h2 id="uses">Uses of API Level in Android</h2>
    321 
    322 <p>The API Level identifier serves a key role in ensuring the best possible
    323 experience for users and application developers: 
    324 
    325 <ul>
    326 <li>It lets the Android platform describe the maximum framework API revision 
    327 that it supports</li>
    328 <li>It lets applications describe the framework API revision that they
    329 require</li>
    330 <li>It lets the system negotiate the installation of applications on the user's
    331 device, such that version-incompatible applications are not installed.</li>
    332 </ul>
    333 
    334 <p>Each Android platform version stores its API Level identifier internally, in
    335 the Android system itself. </p>
    336 
    337 <p>Applications can use a manifest element provided by the framework API &mdash;
    338 <code>&lt;uses-sdk&gt;</code> &mdash; to describe the minimum and maximum API
    339 Levels under which they are able to run, as well as the preferred API Level that
    340 they are designed to support. The element offers three key attributes:</p>
    341 
    342 <ul>
    343 <li><code>android:minSdkVersion</code> &mdash; Specifies the minimum API Level
    344 on which the application is able to run. The default value is "1".</li>
    345 <li><code>android:targetSdkVersion</code> &mdash; Specifies the API Level
    346 on which the application is designed to run. In some cases, this allows the
    347 application to use manifest elements or behaviors defined in the target
    348 API Level, rather than being restricted to using only those defined 
    349 for the minimum API Level.</li>
    350 <li><code>android:maxSdkVersion</code> &mdash; Specifies the maximum API Level
    351 on which the application is able to run. <strong>Important:</strong> Please read the <a
    352 href="{@docRoot}guide/topics/manifest/uses-sdk-element.html"><code>&lt;uses-sdk&gt;</code></a>
    353 documentation before using this attribute.  </li>
    354 </ul>
    355 
    356 <p>For example, to specify the minimum system API Level that an application
    357 requires in order to run, the application would include in its manifest a
    358 <code>&lt;uses-sdk&gt;</code> element with a <code>android:minSdkVersion</code>
    359 attribute. The value of <code>android:minSdkVersion</code> would be the integer
    360 corresponding to the API Level of the earliest version of the Android platform
    361 under which the application can run. </p>
    362 
    363 <p>When the user attempts to install an application, or when revalidating an
    364 appplication after a system update, the Android system first checks the
    365 <code>&lt;uses-sdk&gt;</code> attributes in the application's manifest and
    366 compares the values against its own internal API Level. The system allows the
    367 installation to begin only if these conditions are met:</p>
    368 
    369 <ul>
    370 <li>If a <code>android:minSdkVersion</code> attribute is declared, its value
    371 must be less than or equal to the system's API Level integer. If not declared,
    372 the system assumes that the application requires API Level 1. </li>
    373 <li>If a <code>android:maxSdkVersion</code> attribute is declared, its value
    374 must be equal to or greater than the system's API Level integer. 
    375 If not declared, the system assumes that the application
    376 has no maximum API Level. Please read the <a
    377 href="{@docRoot}guide/topics/manifest/uses-sdk-element.html"><code>&lt;uses-sdk&gt;</code></a>
    378 documentation for more information about how the system handles this attribute.</li>
    379 </ul>
    380 
    381 <p>When declared in an application's manifest, a <code>&lt;uses-sdk&gt;</code>
    382 element might look like this: </p>
    383 
    384 <pre>&lt;manifest&gt;
    385   &lt;uses-sdk android:minSdkVersion="5" /&gt;
    386   ...
    387 &lt;/manifest&gt;</pre>
    388 
    389 <p>The principal reason that an application would declare an API Level in
    390 <code>android:minSdkVersion</code> is to tell the Android system that it is
    391 using APIs that were <em>introduced</em> in the API Level specified. If the
    392 application were to be somehow installed on a platform with a lower API Level,
    393 then it would crash at run-time when it tried to access APIs that don't exist.
    394 The system prevents such an outcome by not allowing the application to be
    395 installed if the lowest API Level it requires is higher than that of the
    396 platform version on the target device.</p>
    397 
    398 <p>For example, the {@link android.appwidget} package was introduced with API
    399 Level 3. If an application uses that API, it must declare a
    400 <code>android:minSdkVersion</code> attribute with a value of "3". The
    401 application will then be installable on platforms such as Android 1.5 (API Level
    402 3) and Android 1.6 (API Level 4), but not on the Android 1.1 (API Level 2) and
    403 Android 1.0 platforms (API Level 1).</p>
    404 
    405 <p>For more information about how to specify an application's API Level
    406 requirements, see the <a
    407 href="{@docRoot}guide/topics/manifest/uses-sdk-element.html"><code>&lt;uses-sdk&gt;</code></a>
    408  section of the manifest file documentation.</p>
    409 
    410 
    411 <h2 id="considerations">Development Considerations</h2>
    412 
    413 <p>The sections below provide information related to API level that you should
    414 consider when developing your application.</p>
    415 
    416 <h3 id="fc">Application forward compatibility</h3>
    417 
    418 <p>Android applications are generally forward-compatible with new versions of
    419 the Android platform.</p>
    420 
    421 <p>Because almost all changes to the framework API are additive, an Android
    422 application developed using any given version of the API (as specified by its
    423 API Level) is forward-compatible with later versions of the Android platform and
    424 higher API levels. The application should be able to run on all later versions
    425 of the Android platform, except in isolated cases where the application uses a
    426 part of the API that is later removed for some reason. </p>
    427 
    428 <p>Forward compatibility is important because many Android-powered devices
    429 receive over-the-air (OTA) system updates. The user may install your
    430 application and use it successfully, then later receive an OTA update to a new
    431 version of the Android platform. Once the update is installed, your application
    432 will run in a new run-time version of the environment, but one that has the API
    433 and system capabilities that your application depends on. </p>
    434 
    435 <p>In some cases, changes <em>below</em> the API, such those in the underlying
    436 system itself, may affect your application when it is run in the new
    437 environment. For that reason it's important for you, as the application
    438 developer, to understand how the application will look and behave in each system
    439 environment. To help you test your application on various versions of the Android
    440 platform, the Android SDK includes multiple platforms that you can download.
    441 Each platform includes a compatible system image that you can run in an AVD, to
    442 test your application. </p>
    443 
    444 <h3 id="bc">Application backward compatibility</h3>
    445 
    446 <p>Android applications are not necessarily backward compatible with versions of
    447 the Android platform older than the version against which they were compiled.
    448 </p>
    449 
    450 <p>Each new version of the Android platform can include new framework APIs, such
    451 as those that give applications access to new platform capabilities or replace
    452 existing API parts. The new APIs are accessible to applications when running on
    453 the new platform and, as mentioned above, also when running on later versions of
    454 the platform, as specified by API Level. Conversely, because earlier versions of
    455 the platform do not include the new APIs, applications that use the new APIs are
    456 unable to run on those platforms.</p>
    457 
    458 <p>Although it's unlikely that an Android-powered device would be downgraded to
    459 a previous version of the platform, it's important to realize that there are
    460 likely to be many devices in the field that run earlier versions of the
    461 platform. Even among devices that receive OTA updates, some might lag and
    462 might not receive an update for a significant amount of time. </p>
    463 
    464 <h3 id="platform">Selecting a platform version and API Level</h3>
    465 
    466 <p>When you are developing your application, you will need to choose
    467 the platform version against which you will compile the application. In
    468 general, you should compile your application against the lowest possible
    469 version of the platform that your application can support. 
    470 
    471 <p>You can determine the lowest possible platform version by compiling the
    472 application against successively lower build targets. After you determine the
    473 lowest version, you should create an AVD using the corresponding platform
    474 version (and API Level) and fully test your application. Make sure to declare a
    475 <code>android:minSdkVersion</code> attribute in the application's manifest and
    476 set its value to the API Level of the platform version. </p>
    477 
    478 <h3 id="apilevel">Declaring a minimum API Level</h3>
    479 
    480 <p>If you build an application that uses APIs or system features introduced in
    481 the latest platform version, you should set the
    482 <code>android:minSdkVersion</code> attribute to the API Level of the latest
    483 platform version. This ensures that users will only be able to install your
    484 application if their devices are running a compatible version of the Android
    485 platform. In turn, this ensures that your application can function properly on
    486 their devices. </p>
    487 
    488 <p>If your application uses APIs introduced in the latest platform version but
    489 does <em>not</em> declare a <code>android:minSdkVersion</code> attribute, then
    490 it will run properly on devices running the latest version of the platform, but
    491 <em>not</em> on devices running earlier versions of the platform. In the latter
    492 case, the application will crash at runtime when it tries to use APIs that don't
    493 exist on the earlier versions.</p>
    494 
    495 <h3 id="testing">Testing against higher API Levels</h3>
    496 
    497 <p>After compiling your application, you should make sure to test it on the
    498 platform specified in the application's <code>android:minSdkVersion</code>
    499 attribute. To do so, create an AVD that uses the platform version required by
    500 your application. Additionally, to ensure forward-compatibility, you should run
    501 and test the application on all platforms that use a higher API Level than that
    502 used by your application. </p>
    503 
    504 <p>The Android SDK includes multiple platform versions that you can use,
    505 including the latest version, and provides an updater tool that you can use to
    506 download other platform versions as necessary. </p>
    507 
    508 <p>To access the updater, use the <code>android</code> command-line tool,
    509 located in the &lt;sdk&gt;/tools directory. You can launch the SDK updater by
    510 executing <code>android sdk</code>. You can
    511 also simply double-click the android.bat (Windows) or android (OS X/Linux) file.
    512 In ADT, you can also access the updater by selecting 
    513 <strong>Window</strong>&nbsp;>&nbsp;<strong>Android SDK
    514 Manager</strong>.</p>
    515 
    516 <p>To run your application against different platform versions in the emulator,
    517 create an AVD for each platform version that you want to test. For more
    518 information about AVDs, see <a
    519 href="{@docRoot}tools/devices/index.html">Creating and Managing Virtual Devices</a>. If
    520 you are using a physical device for testing, ensure that you know the API Level
    521 of the Android platform it runs. See the table at the top of this document for
    522 a list of platform versions and their API Levels. </p>
    523 
    524 <h2 id="provisional">Using a Provisional API Level</h2>
    525 
    526 <p>In some cases, an "Early Look" Android SDK platform may be available. To let
    527 you begin developing on the platform although the APIs may not be final, the
    528 platform's API Level integer will not be specified. You must instead use the
    529 platform's <em>provisional API Level</em> in your application manifest, in order
    530 to build applications against the platform. A provisional API Level is not an
    531 integer, but a string matching the codename of the unreleased platform version.
    532 The provisional API Level will be specified in the release notes for the Early
    533 Look SDK release notes and is case-sensitive.</p>
    534 
    535 <p>The use of a provisional API Level is designed to protect developers and
    536 device users from inadvertently publishing or installing applications based on
    537 the Early Look framework API, which may not run properly on actual devices
    538 running the final system image.</p>
    539 
    540 <p>The provisional API Level will only be valid while using the Early Look SDK
    541 and can only be used to run applications in the emulator. An application using
    542 the provisional API Level can never be installed on an Android device. At the
    543 final release of the platform, you must replace any instances of the provisional
    544 API Level in your application manifest with the final platform's actual API
    545 Level integer.</p>
    546 
    547 
    548 <h2 id="filtering">Filtering the Reference Documentation by API Level</h2>
    549 
    550 <p>Reference documentation pages on the Android Developers site offer a "Filter
    551 by API Level" control in the top-right area of each page. You can use the 
    552 control to show documentation only for parts of the API that are actually 
    553 accessible to your application, based on the API Level that it specifies in 
    554 the <code>android:minSdkVersion</code> attribute of its manifest file. </p>
    555 
    556 <p>To use filtering, select the checkbox to enable filtering, just below the
    557 page search box. Then set the "Filter by API Level" control to the same API
    558 Level as specified by your application. Notice that APIs introduced in a later
    559 API Level are then grayed out and their content is masked, since they would not
    560 be accessible to your application. </p>
    561 
    562 <p>Filtering by API Level in the documentation does not provide a view
    563 of what is new or introduced in each API Level &mdash; it simply provides a way
    564 to view the entire API associated with a given API Level, while excluding API
    565 elements introduced in later API Levels.</p>
    566 
    567 <p>If you decide that you don't want to filter the API documentation, just
    568 disable the feature using the checkbox. By default, API Level filtering is
    569 disabled, so that you can view the full framework API, regardless of API Level.
    570 </p>
    571 
    572 <p>Also note that the reference documentation for individual API elements
    573 specifies the API Level at which each element was introduced. The API Level 
    574 for packages and classes is specified as "Since &lt;api level&gt;" at the 
    575 top-right corner of the content area on each documentation page. The API Level 
    576 for class members is specified in their detailed description headers, 
    577 at the right margin. </p>
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