am 92aaf243: am cf077fdd: Merge "docs: Android Design typo and grammar fixes" into ics-mr1

  </div>

</div>

<h2>UI Bars</h2>

<h2>System Bars</h2>

<p>The UI bars are screen areas dedicated to the display of notifications, communication of device

status, and device navigation. Typically the UI bars are displayed concurrently with your app. Apps

that display immersive content, such as movies or images, can temporarily hide the UI bars to allow

the user to enjoy full screen content without distraction.</p>

<p>The system bars are screen areas dedicated to the display of notifications, communication of device

status, and device navigation. Typically the system bars are displayed concurrently with your app.

Apps that display immersive content, such as movies or images, can temporarily hide the system bars

to allow the user to enjoy full screen content without distraction.</p>

<img src="../static/content/ui_overview_system_ui.png">

  Recents, and also displays a menu for apps written for Android 2.3 or earlier.</p>

</li>

<li>

<h4>System Bar</h4>

<p>Combines the status and navigation bars for display on tablet form factors.</p>

<h4>Combined Bar</h4>

<p>On tablet form factors the status and navigation bars are combined into a single bar at the

  bottom of the screen.</p>

</li>

</ol>

    <img src="../static/content/app_structure_market.png">

    <div class="figure-caption">

      Market's start screen primarily allows navigation into the stores for Apps, Music, Books, and

      Games. It is also enriched with tailored recommendations and promotions that surface content

      of interest to the user. Search is readily available from the action bar.

      Market's start screen primarily allows navigation into the stores for Apps, Music, Books,

      Movies and Games. It is also enriched with tailored recommendations and promotions that

      surface content of interest to the user. Search is readily available from the action bar.

    </div>

  </div>

<p>The Back key also supports a few behaviors not directly tied to screen-to-screen navigation:</p>

<ul>

<li>Back dismisses floating windows (dialogs, popups)</li>

<li>Back dismisses contextual action bars, and remove highlight from selected items</li>

<li>Back dismisses contextual action bars, and removes the highlight from the selected items</li>

<li>Back hides the onscreen keyboard (IME)</li>

</ul>

<h2>Navigation Within Your App</h2>

<h4>App-to-app navigation</h4>

<p>When navigating deep into your app's hierarchy directly from another app via an intent, Back will

return to the referring app.</p>

<p>The Up button is handled is follows:

<p>The Up button is handled as follows:

- If the destination screen is typically reached from one particular screen within your app, Up

  should navigate to that screen.

- Otherwise, Up should navigate to the topmost ("Home") screen of your app.</p>

<p>For example, after choosing to share a book being view in Market, the user navigates directly to the

Gmail's compose screen. From there, Up returns to the Inbox (which happens to be both the typical

referrer to compose, as well as the topmost screen of the app), while Back returns to Market.</p>

<p>For example, after choosing to share a book being viewed in Market, the user navigates directly to

Gmail's compose screen. From there, Up returns to the Inbox (which happens to be both the

typical referrer to compose, as well as the topmost screen of the app), while Back returns to

Market.</p>

<img src="../static/content/navigation_from_outside_up.png">

<h4>System-to-app navigation</h4>

<p>If the your app was reached via the system mechanisms of notifications or home screen widgets, Up

<p>If your app was reached via the system mechanisms of notifications or home screen widgets, Up

behaves as described for app-to-app navigation, above.</p>

<p>For the Back key, you should make navigation more predictably by inserting into the task's back

stack the complete upward navigation path to the app's topmost screen. This way, a user who has

the user is taken to a hierarchy level below your app's top-level, insert navigation into your app's

back stack to allow them to navigate to your app's top level using the system back key. For more

information, see the chapter on <em>System-to-app navigation</em> in the

<a href="../patterns/notifications.html">Navigation</a> design pattern.</p>

<a href="../patterns/navigation.html">Navigation</a> design pattern.</p>

<h4>Timestamps for time sensitive events</h4>

<p>By default, standard Android notifications include a timestamp in the upper right corner. Consider

whether the timestamp is valuable in the context of your notification. If the timestamp is not