docs/html/guide/topics/resources/index.jd

page.title=Application Resources
@jd:body

<div id="qv-wrapper">
<div id="qv">
  <h2>Topics</h2>
  <ol>
    <li><a href="providing-resources.html">Providing Resources</a></li>
    <li><a href="accessing-resources.html">Accessing Resources</a></li>
    <li><a href="runtime-changes.html">Handling Runtime Changes</a></li>
    <li><a href="localization.html">Localization</a></li>
  </ol>

  <h2>Reference</h2>
  <ol>
    <li><a href="available-resources.html">Resource Types</a></li>
  </ol>
</div>
</div>


<p>You should always externalize resources such as images and strings from your application
code, so that you can maintain them independently. Externalizing your
resources also allows you to provide alternative resources that support specific device
configurations such as different languages or screen sizes, which becomes increasingly
important as more Android-powered devices become available with different configurations. In order
to provide compatibility with different configurations, you must organize resources in your
project's {@code res/} directory, using various sub-directories that group resources by type and
configuration.</p>

<div class="figure" style="width:421px">
<img src="{@docRoot}images/resources/resource_devices_diagram1.png" height="137" alt="" />
<p class="img-caption">
<strong>Figure 1.</strong> Two different devices, both using default
resources.</p>
</div>

<div class="figure" style="width:421px">
<img src="{@docRoot}images/resources/resource_devices_diagram2.png" height="137" alt="" />
<p class="img-caption">
<strong>Figure 2.</strong> Two different devices, one using alternative
resources.</p>
</div>

<p>For any type of resource, you can specify <em>default</em> and multiple
<em>alternative</em> resources for your application:</p>
<ul>
  <li>Default resources are those that should be used regardless of
the device configuration or when there are no alternative resources that match the current
configuration.</li>
  <li>Alternative resources are those that you've designed for use with a specific
configuration. To specify that a group of resources are for a specific configuration,
append an appropriate configuration qualifier to the directory name.</li>
</ul>

<p>For example, while your default UI
layout is saved in the {@code res/layout/} directory, you might specify a different UI layout to
be used when the screen is in landscape orientation, by saving it in the {@code res/layout-land/}
directory. Android automatically applies the appropriate resources by matching the
device's current configuration to your resource directory names.</p>

<p>Figure 1 demonstrates how a collection of default resources from an application are applied
to two different devices when there are no alternative resources available. Figure 2 shows
the same application with a set of alternative resources that qualify for one of the device
configurations, thus, the two devices uses different resources.</p>

<p>The information above is just an introduction to how application resources work on Android.
The following documents provide a complete guide to how you can organize your application resources,
specify alternative resources, access them in your application, and more:</p>

<dl>
  <dt><strong><a href="providing-resources.html">Providing Resources</a></strong></dt>
  <dd>What kinds of resources you can provide in your app, where to save them, and how to create
alternative resources for specific device configurations.</dd>
  <dt><strong><a href="accessing-resources.html">Accessing Resources</a></strong></dt>
  <dd>How to use the resources you've provided, either by referencing them from your application
code or from other XML resources.</dd>
  <dt><strong><a href="runtime-changes.html">Handling Runtime Changes</a></strong></dt>
  <dd>How to manage configuration changes that occur while your Activity is running.</dd>
  <dt><strong><a href="localization.html">Localization</a></strong></dt>
  <dd>A bottom-up guide to localizing your application using alternative resources. While this is
just one specific use of alternative resources, it is very important in order to reach more
users.</dd>
  <dt><strong><a href="available-resources.html">Resource Types</a></strong></dt>
  <dd>A reference of various resource types you can provide, describing their XML elements,
attributes, and syntax. For example, this reference shows you how to create a resource for
application menus, drawables, animations, and more.</dd>
</dl>

<!--
<h2>Raw Assets</h2>

<p>An alternative to saving files in {@code res/} is to save files in the {@code
assets/} directory. This should only be necessary if you need direct access to original files and
directories by name. Files saved in the {@code assets/} directory will not be given a resource
ID, so you can't reference them through the {@code R} class or from XML resources. Instead, you can
query data in the {@code assets/} directory like an ordinary file system, search through the
directory and
read raw data using {@link android.content.res.AssetManager}. For example, this can be more useful
when dealing with textures for a game. However, if you only need to read raw data from a file
(such as a video or audio file), then you should save files into the {@code res/raw/} directory and
then read a stream of bytes using {@link android.content.res.Resources#openRawResource(int)}. This
is uncommon, but if you need direct access to original files in {@code assets/}, refer to the {@link
android.content.res.AssetManager} documentation.</p>
-->