docs/html/preview/tv/design/patterns.jd

page.title=Patterns for TV
page.tags="design"
@jd:body

<p>As a developer of apps for TV, you should follow certain patterns to enable users to
  quickly understand and operate your app. This section describes recommended design patterns
  for TV apps.</p>

<h2>Navigation, Focus and Selection</h2>

<p>Users typically navigate TV devices using a directional pad (D-Pad). This type of controller
  limits movement to up, down, left, and right. As you design your app for TV, make sure your
  user interface has clear paths for two-axis navigation by aligning objects in lists and
  grids.</p>

<img src="{@docRoot}preview/tv/design/images/focus.png" alt="TV navigation and focus diagram" />

<p>A key aspect of making your application work well with a D-Pad controller is to make sure
  that there is always an object that is obviously in focus. Your app must clearly indicate
  what object is focused, so users can easily see what action they can take. Use scale, shadow
  brightness, opacity, animation or a combination of these attributes to help users see a focused
  object.</p>


<h2>Icons</h2>

<p>Apps on TV devices require some additional icon images for presentation in the system
  user interface, including home screen launcher images (banners) and recommendation icons.
  The visual specifications for these icons are shown below.</p>


<h3>Banners</h3>

<p>App Banners represent your app on the home screen of TV devices and serve and as a way for
  users to launch your app. Here are specific requirements for a banner image:
</p>

<ul>
  <li>Size: 320 x 180 px, xhdpi resource</li>
  <li>Text should be included in the image. If your app is available in more than one
      language, you must provide versions of the banner image for each supported language.</li>
</ul>


<h3>Recommendation Icons</h3>

<p>Recommendation cards include a small icon that is imposed over a colored background.
  An example and specifications for this icon are shown below:</p>

<img src="{@docRoot}preview/tv/design/images/icon.png" alt="Recommendation icon examples" />

<p>Here are the requirements for recommendation icons:</p>

<ul>
  <li>Monocolor: size 16x16dp, white (#fff) icon with transparent background, PNG format</li>
  <li>Graphics should be centered within the icon image</li>
</ul>

<p class="note">
  <strong>Note:</strong> Your app icon image may be desaturated and blended for some card
  displays.
</p>


<h2>Background Images</h2>

<p>Background images are displayed in the background of your app to provide additional visual
  interest, information, or branding. The BrowseFragment and DetailsFragment classes in the Leanback
  support library provide specific support for background images and for updating them as items gain
  and lose focus. Here are the specific requirements for background images:</p>

<ul>
  <li>Full color, 1920 x 1080 pixels</li>
</ul>

<p class="note">
  <strong>Note:</strong> If the image does not meet this requirement, it is scaled to fit.
</p>

<h2>Audio Feedback</h2>

<p>Sounds on Android TV bring a cinematic quality to the interaction experience. You should
  consider adding sounds for user actions or to provide feedback when a user is only partially
  visually engaged with the screen (e.g., because they are distracted or multitasking).
  You should also consider using sounds as alternatives to visual messages, for example to indicate
  that a user has reached the end of a list or is trying to navigate to an undefined location.</p>