docs: Accessibility DevGuide, Jelly Bean edition

          <li><a href="<?cs var:toroot ?>guide/topics/ui/accessibility/apps.html">

              <span class="en">Making Applications Accessible</span>

            </a></li>

          <li><a href="<?cs var:toroot ?>guide/topics/ui/accessibility/checklist.html">

              <span class="en">Accessibility Developer Checklist</span>

            </a></li>

          <li><a href="<?cs var:toroot ?>guide/topics/ui/accessibility/services.html">

              <span class="en">Building Accessibility Services</span>

            </a></li>

page.title=Accessibility Developer Checklist

parent.title=Accessibility

parent.link=index.html

@jd:body

<div id="qv-wrapper">

<div id="qv">

  <h2>In this document</h2>

  <ol>

    <li><a href="#requirements">Accessibility Requirements</a></li>

    <li><a href="#recommendations">Accessibility Recommendations</a></li>

    <li><a href="#special-cases">Special Cases and Considerations</a></li>

  </ol>

  <h2>See also</h2>

  <ol>

    <li><a href="{@docRoot}design/patterns/accessibility.html">Android Design: Accessibility</a></li>

    <li><a href="{@docRoot}tools/testing/testing_accessibility.html">Accessibility Testing Checklist</a></li>

    <li><a href="{@docRoot}training/accessibility/index.html">Training: Implementing Accessibility</a></li>

    <li><a href="{@docRoot}training/design-navigation/index.html">Designing Effective Navigation</a></li>

  </ol>

</div>

</div>

<p>Making an application accessible is about a deep commitment to usability, getting the

details right and delighting your users. This document provides a checklist of accessibility

requirements, recommendations and considerations to help you make sure your application is

accessible. Following this checklist does not guarantee your application is accessible, but it's a

good place to start.</p>

<p>Creating an accessible application is not just the responsibility of developers. Involve your

design and testing folks as well, and make them are aware of the guidelines for these other stages

of development:</p>

<ul>

  <li><a href="{@docRoot}design/patterns/accessibility.html">Android Design: Accessibility</a></li>

  <li><a href="{@docRoot}tools/testing/testing_accessibility.html">Accessibility Testing

    Checklist</a></li>

</ul>

<p>In most cases, creating an accessible Android application does not require extensive code

restructuring. Rather, it means working through the subtle details of how users interact with your

application, so you can provide them with feedback they can sense and understand. This checklist

helps you focus on the key development issues to get the details of accessibility right.</p>

<h2 id="requirements">Accessibility Requirements</h2>

<p>The following steps must be completed in order to ensure a minimum level of application

  accessibility.</p>

<ol>

  <li><strong>Describe user interface controls:</strong> Provide content

    <a href="{@docRoot}guide/topics/ui/accessibility/apps.html#label-ui">descriptions</a> for user

    interface components that do not have visible text, particularly

    {@link android.widget.ImageButton}, {@link android.widget.ImageView}

    and {@link android.widget.CheckBox} components. Use the

    <a href="{@docRoot}reference/android/view/View.html#attr_android:contentDescription">

    {@code android:contentDescription}</a> XML layout attribute or the {@link

    android.view.View#setContentDescription} method to provide this information for accessibility

    services. (Exception: <a href="#decorative">decorative graphics</a>)</li>

  <li><strong>Enable focus-based navigation:</strong> Make sure

    <a href="{@docRoot}guide/topics/ui/accessibility/apps.html#focus-nav">users can navigate</a>

    your screen layouts using hardware-based or software directional controls (D-pads, trackballs,

    keyboards and navigation gestures). In a few cases, you may need to make user interface components

    <a href="{@docRoot}reference/android/view/View.html#attr_android:focusable">focusable</a>

    or change the <a href="{@docRoot}guide/topics/ui/accessibility/apps.html#focus-order">focus

    order</a> to be more logical for user actions.</li>

  <li><strong>Custom view controls:</strong> If you build

    <a href="{@docRoot}guide/topics/ui/custom-components.html">custom interface controls</a> for

    your application, <a href="{@docRoot}guide/topics/ui/accessibility/apps.html#custom-views">

    implement accessibility interfaces</a> for your custom views and provide content descriptions.

    For custom controls that are intended to be compatible with versions of Android back to 1.6,

    use the <a href="{@docRoot}tools/extras/support-library.html">Support Library</a> to implement

    the latest accessibility features.</li>

  <li><strong>No audio-only feedback:</strong> Audio feedback must always have a secondary

    feedback mechanism to support users who are deaf or hard of hearing. For example, a sound alert

    for the arrival of a message must be accompanied by a system

    {@link android.app.Notification}, haptic feedback (if available) or other visual alert.</li>

  <li><strong>Test:</strong> Test accessibility by navigating your application

    using directional controls, and using eyes-free navigation with TalkBack enabled.

    For more accessibility testing information, see the

    <a href="{@docRoot}tools/testing/testing_accessibility.html">Accessibility Testing

    Checklist</a>.</li>

</ol>

<h2 id="recommendations">Accessibility Recommendations</h2>

<p>The following steps are recommended for ensuring the accessibility of your application. If you

  do not take these actions, it may impact the overall accessibility and quality of your

  application.</p>

<ol>

  <li><strong>Android Design Accessibility Guidelines:</strong> Before building your layouts,

    review and follow the accessibility guidelines provided in the

    <a href="{@docRoot}design/patterns/accessibility.html">Design guidelines</a>.</li>

  <li><strong>Framework-provided controls:</strong> Use Android's built-in user interface

    controls whenever possible, as these components provide accessibility support by default.</li>

  <li><strong>Temporary or self-hiding controls and notifications:</strong> Avoid having user

    interface controls that fade out or disappear after a certain amount of time. If this behavior

    is important to your application, provide an alternative interface for these functions.</li>

</ol>

<h2 id="special-cases">Special Cases and Considerations</h2>

<p>The following list describes specific situations where action should be taken to ensure an

  accessible app. Review this list to see if any of these special cases and considerations apply to

  your application, and take the appropriate action.</p>

<ol>

  <li><strong>Text field hints:</strong> For {@link android.widget.EditText} fields, provide an

    <a href="{@docRoot}reference/android/widget/TextView.html#attr_android:hint">android:hint</a>

    attribute <em>instead</em> of a content description, to help users understand what content is

    expected when the text field is empty and allow the contents of the field to be spoken when

    it is filled.</li>

  <li><strong>Custom controls with high visual context:</strong> If your application contains a

    <a href="{@docRoot}guide/topics/ui/custom-components.html">custom control</a> with a high degree

    of visual context (such as a calendar control), default accessibility services processing may

    not provide adequate descriptions for users, and you should consider providing a

    <a href="{@docRoot}guide/topics/ui/accessibility/apps.html#virtual-hierarchy">virtual

    view hierarchy</a> for your control using

    {@link android.view.accessibility.AccessibilityNodeProvider}.</li>

  <li><strong>Custom controls and click handling:</strong> If a custom control in your

    application performs specific handling of user touch interaction, such as listening with

    {@link android.view.View#onTouchEvent} for {@link android.view.MotionEvent#ACTION_DOWN

    MotionEvent.ACTION_DOWN} and {@link android.view.MotionEvent#ACTION_UP MotionEvent.ACTION_UP}

    and treating it as a click event, you must trigger an {@link

    android.view.accessibility.AccessibilityEvent} equivalent to a click and provide a way for

    accessibility services to perform this action for users. For more information, see

    <a href="{@docRoot}guide/topics/ui/accessibility/apps.html#custom-touch-events">Handling custom

    touch events</a>.</li>

  <li><strong>Controls that change function:</strong> If you have buttons or other controls

    that change function during the normal activity of a user in your application (for example, a

    button that changes from <strong>Play</strong> to <strong>Pause</strong>), make sure you also

    change the <a href="{@docRoot}reference/android/view/View.html#attr_android:contentDescription">

    {@code android:contentDescription}</a> of the button appropriately.</li>

  <li><strong>Prompts for related controls:</strong> Make sure sets of controls which provide a

    single function, such as the {@link android.widget.DatePicker}, provide useful audio feedback

    when an user interacts with the individual controls.</li>

  <li><strong>Video playback and captioning:</strong> If your application provides video

    playback, it must support captioning and subtitles to assist users who are deaf or hard of

    hearing. Your video playback controls must also clearly indicate if captioning is available for

    a video and provide a clear way of enabling captions.</li>

  <li><strong>Supplemental accessibility audio feedback:</strong> Use only the Android accessibility

    framework to provide accessibility audio feedback for your app. Accessibility services such as

    <a href="https://play.google.com/store/apps/details?id=com.google.android.marvin.talkback"

    >TalkBack</a> should be the only way your application provides accessibility audio prompts to

    users. Provide the prompting information with a

    <a href="{@docRoot}reference/android/view/View.html#attr_android:contentDescription">{@code

    android:contentDescription}</a> XML layout attribute or dynamically add it using accessibility

    framework APIs. For example, if your application takes action that you want to announce to a

    user, such as automatically turning the page of a book, use the {@link

    android.view.View#announceForAccessibility} method to have accessibility services speak this

    information to the user.</li>

  <li><strong>Custom controls with complex visual interactions:</strong> For custom controls that

    provide complex or non-standard visual interactions, provide a

    <a href="{@docRoot}guide/topics/ui/accessibility/apps.html#virtual-hierarchy">virtual view

    hierarchy</a> for your control using {@link android.view.accessibility.AccessibilityNodeProvider}

    that allows accessibility services to provide a simplified interaction model for the user. If

    this approach is not feasible, consider providing an alternate view that is accessible.</li>

  <li><strong>Sets of small controls:</strong> If you have controls that are smaller than

    the minimum recommended touch size in your application screens, consider grouping these controls

    together using a {@link android.view.ViewGroup} and providing a

    <a href="{@docRoot}reference/android/view/View.html#attr_android:contentDescription">{@code

    android:contentDescription}</a> for the group.</li>

  <li id="decorative"><strong>Decorative images and graphics:</strong> Elements in application

    screens that are purely decorative and do not provide any content or enable a user action should

    not have accessibility content descriptions.</li>

</ol>

  <h2>Topics</h2>

  <ol>

  <li><a href="{@docRoot}guide/topics/ui/accessibility/apps.html">Making Applications Accessible</a>

    </li>

  <li><a href="{@docRoot}guide/topics/ui/accessibility/services.html">Building Accessibility

    Services</a></li>

  <li><a href="apps.html">

    Making Applications Accessible</a></li>

  <li><a href="checklist.html">

    Accessibility Developer Checklist</a></li>

  <li><a href="services.html">

    Building Accessibility Services</a></li>

  </ol>

  <h2>Key classes</h2>

  <h2>See also</h2>

  <ol>

    <li>{@link android.view.accessibility.AccessibilityEvent}</li>

    <li>{@link android.accessibilityservice.AccessibilityService}</li>

    <li><a href="{@docRoot}design/patterns/accessibility.html">Android Design: Accessibility</a></li>

    <li><a href="{@docRoot}training/accessibility/index.html">Training: Implementing Accessibility</a></li>

    <li><a href="{@docRoot}tools/testing/testing_accessibility.html">Accessibility Testing Checklist</a></li>

  </ol>

  <h2>See also</h2>

  <h2>Related Videos</h2>

  <ol>

    <li><a href="{@docRoot}training/accessibility/index.html">Implementing Accessibility</a></li>

    <li>

      <iframe title="Google I/O 2012 - Making Android Apps Accessible"

          width="210" height="160"

          src="http://www.youtube.com/embed/q3HliaMjL38?rel=0&hd=1"

          frameborder="0" allowfullscreen>

      </iframe>

    <li>

  </ol>

</div>

</div>

<p>Many Android users have disabilities that require them to interact with their Android devices in

different ways. These include users who have visual, physical or age-related disabilities that

prevent them from fully seeing or using a touchscreen.</p>

<p>Many Android users have different abilities that require them to interact with their Android

devices in different ways. These include users who have visual, physical or age-related limitations

that prevent them from fully seeing or using a touchscreen, and users with hearing loss who may not

be able to perceive audible information and alerts.</p>

<p>Android provides accessibility features and services for helping these users navigate their

devices more easily, including text-to-speech, haptic feedback, trackball and D-pad navigation that

augment their experience. Android application developers can take advantage of these services to

make their applications more accessible and also build their own accessibility services.</p>

devices more easily, including text-to-speech, haptic feedback, gesture navigation, trackball and

directional-pad navigation. Android application developers can take advantage of these services to

make their applications more accessible.</p>

<p>Android developers can also build their own accessibility services, which can provide

enhanced usability features such as audio prompting, physical feedback, and alternative navigation

modes. Accessibility services can provide these enhancements for all applications, a set of

applications or just a single app.</p>

<p>The following topics show you how to use the Android framework to make applications more

accessible.</p>

<dl>

  <dt><strong><a href="{@docRoot}guide/topics/ui/accessibility/apps.html">Making Applications

Accessible</a></strong>

  <dt><strong><a href="{@docRoot}guide/topics/ui/accessibility/apps.html">

  Making Applications Accessible</a></strong>

  </dt>

  <dd>Development practices and API features to ensure your application is accessible to users with

disabilities.</dd>

  <dt><strong><a href="{@docRoot}guide/topics/ui/accessibility/services.html">Building Accessibility

Services</a></strong>

  <dt><strong><a href="{@docRoot}guide/topics/ui/accessibility/checklist.html">

  Accessibility Developer Checklist</a></strong>

  </dt>

  <dd>A checklist to help developers ensure that their applications are accessible.</dd>

  <dt><strong><a href="{@docRoot}guide/topics/ui/accessibility/services.html">

  Building Accessibility Services</a></strong>

  </dt>

  <dd>How to use API features to build services that make other applications more accessible for

users.</dd>