1page.title=Screen Compatibility Mode 2parent.title=Supporting Multiple Screens 3parent.link=screens_support.html 4 5@jd:body 6 7 8<div id="qv-wrapper"> 9<div id="qv"> 10 11<h2>In this document</h2> 12<ol> 13 <li><a href="#Disable">Disabling Screen Compatibility Mode</a></li> 14 <li><a href="#Enable">Enabling Screen Compatibility Mode</a></li> 15</ol> 16<h2>See also</h2> 17<ol> 18 <li><a href="{@docRoot}guide/practices/screens_support.html">Supporting Multiple Screens</a></li> 19 <li><a href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code 20<supports-screens>}</a></li> 21</ol> 22</div> 23</div> 24 25<div class="figure" style="width:500px;"> 26<a href="{@docRoot}images/screens_support/compat-zoom.png"> 27<img src="{@docRoot}images/screens_support/compat-zoom-thumb.png" alt="" /> 28</a> 29<p class="img-caption"><strong>Figure 1.</strong> An application running in compatibility mode 30on an Android 3.2 tablet.</p> 31</div> 32 33<div class="figure" style="width:500px;"> 34<a href="{@docRoot}images/screens_support/compat-stretch.png"> 35<img src="{@docRoot}images/screens_support/compat-stretch-thumb.png" alt="" /> 36</a> 37<p class="img-caption"><strong>Figure 2.</strong> The same application from figure 1, with 38compatibility mode disabled.</p> 39</div> 40 41<p class="caution"><strong>Notice:</strong> If you've developed an application for a version of 42Android lower than Android 3.0, but it does resize properly for larger screens such as tablets, you 43should disable screen compatibility mode in order to maintain the best user experience. To learn how 44to quickly disable the user option, jump to <a href="#Disable">Disabling Screen Compatibility 45Mode</a>.</p> 46 47<p>Screen compatibility mode is an escape hatch for applications that are not properly designed 48to resize for larger screens such as tablets. Since Android 1.6, Android has supported a 49variety of screen sizes and does most of the work to resize application layouts so that they 50properly fit each screen. However, if your application does not successfully follow the guide to 51<a href="{@docRoot}guide/practices/screens_support.html">Supporting Multiple Screens</a>, 52then it might encounter some rendering issues on larger screens. For applications with this 53problem, screen compatibility mode can make the application a little more usable on larger 54screens.</p> 55 56<p>There are two versions of screen compatibility mode with slightly different behaviors:</p> 57<dl> 58 <dt>Version 1 (Android 1.6 - 3.1)</dt> 59 <dd>The system draws the application's UI in a "postage stamp" 60window. That is, the system draws the application's layout the same as it would on a 61normal size handset (emulating a 320dp x 480dp screen), with a black border that fills 62the remaining area of the screen. 63 64<p>This was introduced with Android 1.6 to handle apps that were designed only for the 65original screen size of 320dp x 480dp. Because there are so few active devices remaining that run 66Android 1.5, almost all applications should be developed against Android 1.6 or greater and 67should not have version 1 of screen compatibility mode enabled for larger screens. This version 68is considered obsolete.</p> 69 <p>To disable this version of screen compatibility mode, you simply need to set <a 70href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">{@code 71android:minSdkVersion}</a> or <a 72href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code 73android:targetSdkVersion}</a> to {@code "4"} or higher, or set <a 74href="{@docRoot}guide/topics/manifest/supports-screens-element.html#resizeable">{@code 75android:resizeable}</a> to {@code "true"}.</p> 76 </dd> 77 78 <dt>Version 2 (Android 3.2 and greater)</dt> 79 <dd>The system draws the application's layout the same as 80it would on a normal size handset (approximately emulating a 320dp x 480dp screen), then scales it 81up to fill the screen. This essentially "zooms" in on your layout to make it bigger, 82which will usually cause artifacts such as blurring and pixelation in your UI. 83 <p>This was introduced with Android 3.2 to further 84assist applications on the latest tablet devices when the applications have not yet 85implemented techniques for <a 86href="{@docRoot}guide/practices/screens_support.html">Supporting Multiple 87Screens</a>.</p> 88 <p>In general, large screen devices running Android 3.2 or higher allow users to enable 89screen compatibility mode when the application does not <strong>explicitly declare that it supports 90large screens</strong> in the manifest file. When this is the case, an icon (with 91outward-pointing arrows) appears next to the clock in the system bar, which allows the user to 92toggle screen compatibility mode on and off (figure 3). An application can also explicitly 93declare that it <em>does not</em> support large screens such that screen compatibility mode 94is always enabled and the user cannot disable it. (How to declare your application's 95support for large screens is discussed in the following sections.)</p></dd> 96</dl> 97 98<img src="{@docRoot}images/screens_support/compat-toggle.png" alt="" /> 99<p class="img-caption"><strong>Figure 3.</strong> The pop up menu to toggle screen compatibility 100mode (currently disabled, so normal resizing occurs).</p> 101 102<p>As a developer, you have control over when your application uses screen compatibility mode. The 103following sections describe how you can choose to disable or enable screen compatibility mode for 104larger screens when running Android 3.2 or higher.</p> 105 106 107<h2 id="Disable">Disabling Screen Compatibility Mode</h2> 108 109<p>If you've developed your application primarily for versions of Android lower than 3.0, but 110<strong>your application does resize properly</strong> for larger screens such as tablets, 111<strong>you should disable screen compatibility mode</strong> in order to maintain the best user 112experience. Otherwise, users may enable screen compatibility mode and experience your application in 113a less-than-ideal format.</p> 114 115<p>By default, screen compatibility mode for devices running Android 3.2 and higher is offered to 116users as an optional feature when one of the following is true:</p> 117 118<ul> 119 <li>Your application has set both <a 120href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">{@code android:minSdkVersion}</a> 121and <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code 122android:targetSdkVersion}</a> to {@code "10"} or lower and <strong>does not explicitly 123declare support</strong> for large screens using the <a 124href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code 125<supports-screens>}</a> element.</li> 126 127 <li>Your application has set either <a 128href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">{@code android:minSdkVersion}</a> 129or <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code 130android:targetSdkVersion}</a> to {@code "11"} or higher and <strong>explicitly declares that it does 131not support</strong> large screens, using the <a 132href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code 133<supports-screens>}</a> element.</li> 134</ul> 135 136<p>To completely disable the user option for screen compatibility mode and remove the icon in the 137system bar, you can do one of the following:</p> 138 139<ul> 140 <li><strong>Easiest:</strong> 141 <p>In your manifest file, add the <a 142href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code 143<supports-screens>}</a> element and specify the <a 144href="{@docRoot}guide/topics/manifest/supports-screens-element.html#xlarge">{@code 145android:xlargeScreens}</a> attribute to {@code "true"}:</p> 146<pre> 147<supports-screens android:xlargeScreens="true" /> 148</pre> 149 <p>That's it. This declares that your application supports all larger screen sizes, so the 150system will always resize your layout to fit the screen. This works regardless of what values 151you've set in the <a 152href="{@docRoot}guide/topics/manifest/uses-sdk-element.html">{@code <uses-sdk>}</a> 153attributes.</p> 154 </li> 155 156 <li><strong>Easy but has other effects:</strong> 157 <p>In your manifest's <a 158href="{@docRoot}guide/topics/manifest/uses-sdk-element.html">{@code <uses-sdk>}</a> 159element, set <a 160href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code 161android:targetSdkVersion}</a> to {@code "11"} or higher:</p> 162<pre> 163<uses-sdk android:minSdkVersion="4" android:targetSdkVersion="11" /> 164</pre> 165 <p>This declares that your application supports Android 3.0 and, thus, is designed to 166work on larger screens such as tablets.</p> 167 <p class="caution"><strong>Caution:</strong> When running on Android 3.0 and greater, this also 168has the effect of enabling the Holographic theme for you UI, adding the <a 169href="{@docRoot}guide/topics/ui/actionbar.html">Action Bar</a> to your activities, and removing the 170Options Menu button in the system bar.</p> 171 <p>If screen compatibility mode is still enabled after you change this, check your manifest's <a 172href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code 173<supports-screens>}</a> and be sure that there are no attributes set {@code "false"}. The best 174practice is to always explicitly declare your support for different screen sizes using the <a 175href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code 176<supports-screens>}</a> element, so you should use this element anyway.</p> 177 <p>For more information about updating your application to target Android 3.0 devices, read <a 178href="{@docRoot}guide/practices/optimizing-for-3.0.html">Optimizing Apps for Android 1793.0</a>.</p> 180 </li> 181<!-- 182 <li><strong>Most control</strong> (but you must compile against Android 3.2 or higher): 183 <p>In your manifest file, add the <a 184href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code 185<supports-screens>}</a> element and specify the {@code android:compatibleWidthLimitDp} 186attribute to any value <em>higher than</em> {@code "320"}:</p> 187<pre> 188<supports-screens android:compatibleWidthLimitDp="720" /> 189</pre> 190 <p>Using this technique allows you to specify exactly what your application's limit is for 191layout resizing. Normally, only applications that are already built against Android 3.2 (or 192higher) use this attribute, because the primary intention is to specify at what size should screen 193compatibility mode actually be offered to users.</p> 194 <p class="note"><strong>Note:</strong> Currently, screen compatibility mode only emulates 195handset screens with a 320dp width, so screen compatibility mode is not applied to any device if 196your value for {@code android:compatibleWidthLimitDp} is larger than 320.</p> 197 </li> 198 --> 199</ul> 200 201 202 203<h2 id="Enable">Enabling Screen Compatibility Mode</h2> 204 205<p>When your application is targeting Android 3.2 (API level 13) or higher, you can affect 206whether compatibility mode is enabled for certain screens by using the <a 207href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code 208<supports-screens>}</a> element.</p> 209 210<p class="note"><strong>Note:</strong> Screen compatibility mode is <strong>not</strong> a mode in 211which you should want your application to run—it causes pixelation and blurring in your UI, 212due to zooming. The proper way to make your application work well on large screens is to follow the 213guide to <a 214href="{@docRoot}guide/practices/screens_support.html">Supporting Multiple Screens</a> and 215provide alternative layouts for different screen sizes.</p> 216 217<p>By default, when you've set either <a 218href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">{@code 219android:minSdkVersion}</a> or <a 220href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code 221android:targetSdkVersion}</a> to {@code "11"} or higher, screen compatibility mode is 222<strong>not</strong> available to users. If either of these are true and your application does not 223resize properly for larger screens, you can choose to enable screen compatibility mode in one 224of the following ways:</p> 225 226<ul> 227 <li>In your manifest file, add the <a 228href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code 229<supports-screens>}</a> element and specify the <a 230href="{@docRoot}guide/topics/manifest/supports-screens-element.html#compatibleWidth">{@code 231android:compatibleWidthLimitDp}</a> attribute to {@code "320"}:</p> 232<pre> 233<supports-screens android:compatibleWidthLimitDp="320" /> 234</pre> 235 <p>This indicates that the maximum "smallest screen width" for which your application is designed 236is 320dp. This way, any devices with their smallest side being larger than this value will offer 237screen compatibility mode as a user-optional feature.</p> 238 <p class="note"><strong>Note:</strong> Currently, screen compatibility mode only emulates 239handset screens with a 320dp width, so screen compatibility mode is not applied to any device if 240your value for <a 241href="{@docRoot}guide/topics/manifest/supports-screens-element.html#compatibleWidth">{@code 242android:compatibleWidthLimitDp}</a> is larger than 320.</p> 243 </li> 244 245 <li>If your application is functionally broken when resized for large screens and you want to 246force users into screen compatibility mode (rather than simply providing the option), you can use 247the <a href="{@docRoot}guide/topics/manifest/supports-screens-element.html#largestWidth">{@code 248android:largestWidthLimitDp}</a> attribute: 249<pre> 250<supports-screens android:largestWidthLimitDp="320" /> 251</pre> 252 <p>This works the same as <a 253href="{@docRoot}guide/topics/manifest/supports-screens-element.html#compatibleWidth">{@code 254android:compatibleWidthLimitDp}</a> except it force-enables 255screen compatibility mode and does not allow users to disable it.</p> 256 </li> 257</ul>
