Merge "docs: Updates to L Preview Highlights." into klp-modular-dev

      <li><a href="#ART">New Android Runtime (ART)</a></li>

      <li><a href="#BehaviorNotifications">If your app implements notifications...</a></li>

      <li><a href="#BehaviorMediaControl">If your app uses RemoteControlClient...</a></li>

      <li><a href="#BehaviorFullscreen">If your app uses fullScreenIntent...</a></li>

      <li><a href="#BehaviorGetRecentTasks">If your app uses ActivityManager.getRecentTasks()...</a></li>

    </ol>

  </li>

  <li><a href="#Power">Power Efficiency</a>

    <ol>

      <li><a href="#JobScheduler">Scheduling Jobs</a></li>

      <li><a href="#PowerMeasurementTools">Developer tools and APIs for power measurement</a>

      <li><a href="#PowerMeasurementTools">Developer tools for power measurement</a>

    </ol>

  </li>

  <li><a href="#Enterprise">Enterprise</a>

    <ol>

      <li><a href="#ManagedProvisioning">Managed provisioning</a></li>

      <li><a href="#LockToAppMode">Lock-to-App mode</a></li>

    </ol>

  </li>

  <li><a href="#Printing">Printing Framework</a>

</div>

</div>

<p>The L Developer Preview gives you an advance look at the upcoming release for

the Android platform,

which offers new features for users and app developers. This document provides

an introduction to the most notable APIs.</p>

<p>The L Developer Preview gives you an advance look at the upcoming release

for the Android platform, which offers new features for users and app

developers. This document provides an introduction to the most notable APIs.</p>

<p>The L Developer Preview is intended for <strong>developer early adopters</strong> and

<strong>testers</strong>. If you are interested in influencing the direction of the

Android framework, <a href="{@docRoot}preview/setup-sdk.html">give the L

Developer Preview a try</a> and send us your feedback!</p>

<p>The L Developer Preview is intended for <strong>developer early

adopters</strong> and <strong>testers</strong>. If you are interested in

influencing the direction of the Android framework,

<a href="{@docRoot}preview/setup-sdk.html">give the L Developer Preview a

try</a> and send us your feedback!</p>

<p class="caution"><strong>Caution:</strong> Do not not publish apps

that use the L Developer Preview to the Google Play store.</p>

<h3 id="ART">New Android Runtime (ART)</h3>

<p>The 4.4 release introduced a new, experimental Android runtime, ART. Under

4.4, ART was optional, and the default runtime remained Dalvik. With the L Developer Preview, ART is

now the default runtime.</p>

4.4, ART was optional, and the default runtime remained Dalvik. With the L

Developer Preview, ART is now the default runtime.</p>

<p>For an overview of ART's new features, see

<a href="https://source.android.com/devices/tech/dalvik/art.html">Introducing

backgrounds to match the new material design widgets. Make sure that all your

notifications look right with the new color scheme:</p>

<div class="figure" style="width:220px">

  <img src="images/hun-example.png"

    srcset="images/hun-example@2x.png 2x"

    alt="" width="220" height="372" id="figure1" />

  <p class="img-caption">

    <strong>Figure 1.</strong> Fullscreen activity showing a heads-up notification

  </p>

</div>

<ul>

  <li>Update or remove assets that involve color.</li>

<p>If you are currently adding sounds and vibrations to your notifications by

using the {@link android.media.Ringtone}, {@link android.media.MediaPlayer},

or {@link android.os.Vibrator} classes, remove this code so that

the system can present notifications correctly in <a href="#DoNotDisturb">Do Not Disturb</a> mode.

Instead, use the {@link android.app.Notification.Builder} methods instead to add

sounds and vibration.</p>

the system can present notifications correctly in <a href="#DoNotDisturb">Do Not Disturb</a> mode. Instead, use the {@link android.app.Notification.Builder} methods instead to add sounds and vibration.</p>

<p>Notifications now appear in a small floating window

(also called a <em>heads-up notification</em>) when the device is active

(that is, the device is unlocked and its screen is on). These notifications

appear similar to the compact form of your notification, except that the

heads-up notification also shows action buttons. Users can act on, or dismiss,

a heads-up notification without leaving the current app.</p>

<p>Examples of conditions that may trigger heads-up notifications include:</p>

<ul>

  <li>The user's activity is in fullscreen mode (the app uses

{@link android.app.Notification#fullScreenIntent}), or</li>

  <li>The notification has high priority and uses ringtones or

    vibrations</li>

</ul>

<p>If your app implements notifications under those scenarios, make sure that

heads-up notifications are presented correctly.</p>

<h3 id="BehaviorMediaControl">If your app uses RemoteControlClient...</h3>

<p>Lockscreens in the L Developer Preview do not show transport controls for your

{@link android.media.RemoteControlClient}. Instead, your app can provide

media playback control from the lockscreen through a media notification. This

<p>Lockscreens in the L Developer Preview do not show transport controls for

your {@link android.media.RemoteControlClient}. Instead, your app can provide

media playback control from the lockscreen through a notification. This

gives your app more control over the presentation of media buttons, while

providing a consistent experience for users across the lockscreen and

unlocked device.</p>

<p>The L Developer Preview introduces a new {@code android.app.Notification.MediaStyle} template which is recommended for this purpose. {@code MediaStyle} converts notification actions that you added with {@link android.app.Notification.Builder#addAction(int, java.lang.CharSequence, android.app.PendingIntent) Notification.Builder.addAction()} into compact buttons embedded in your app's media playback notifications.</p>

<p>If you are using the new

{@code android.media.session.MediaSession} class (see <a href="#MediaPlaybackControl">Media Playback Control</a> below), attach your session

token with {@code Notification.MediaStyle.setMediaToken()} to inform the

system that this notification controls an ongoing media session.</p>

<p>Call {@code

Notification.Builder.setVisibility(Notification.VISIBILITY_PUBLIC)} to mark a

notification as safe to display on the lockscreen (even when the lockscreen is

secured with a PIN, pattern, or password). For more information, see

notification as safe to show atop any lockscreen (secure or otherwise). For more information, see

<a href="#LockscreenNotifications">Lockscreen Notifications</a>.</p>

<h3 id="BehaviorFullscreen">If your app uses fullScreenIntent...</h3>

<p>Notifications now appear in a small floating window if all these conditions

are met:</p>

<ul>

  <li>The user’s activity is in fullscreen mode,</li>

  <li>The screen is on, and</li>

  <li>The device is unlocked</li>

</ul>

<p>If your app implements fullscreen activities, make sure that

these heads-up notifications are presented correctly.</p>

<h3 id="BehaviorGetRecentTasks">If your app uses ActivityManager.getRecentTasks()...</h3>

<p>With the introduction of the new <em>concurrent documents and activities tasks</em> feature in the upcoming

<h3 id="MaterialDesign">Material design support</h3>

<p>The upcoming release adds support for Android's new <em>material</em> design

style. You can create

apps with material design that are visually dynamic and have UI element transitions

<ul>

<li>{@code VISIBILITY_PRIVATE}. Shows basic information, such as the

notification’s icon, but hides the notification’s full content. If you want to

provide a redacted public version of your notification for the system to display

on a secure lockscreen, create a public notification object and put a reference

to it in the private notification's {@code publicVersion} field.</li>

<li>{@code VISIBILITY_PUBLIC}. Shows the notification’s full content. This is

  the system default if visibility is left unspecified.</li>

<li>{@code VISIBILITY_SECRET}. Shows only the most minimal information,

excluding even the notification’s icon.</li>

notification’s icon, but hides the notification’s full content.</li>

<li>{@code VISIBILITY_PUBLIC}. Shows the notification’s full content.</li>

<li>{@code VISIBILITY_SECRET}. Shows nothing, excluding even the

notification’s icon.</li>

</ul>

<p>When {@code VISIBILITY_PRIVATE} is set, you can also provide a redacted

version of the notification content that hides personal details. For example,

an SMS app might display a notification that shows "You have 3 new text messages." but hides the message content and senders. To provide this alternative notification, first create the replacement notification using {@link android.app.Notification.Builder}. When you create the private notification object, attach

the replacement notification to it through the {@code Notification.Builder.setPublicVersion()} method.</p>

<h3 id="DoNotDisturb">Do Not Disturb mode</h3>

<p>The L Developer Preview introduces a new <em>Do Not Disturb</em> mode. When

your app is an alarm clock,

you can tag the notification as an alarm so it will wake the user up even if the

device is in <em>Do Not Disturb</em> mode. For more information, see <a

href="NotificationsMetadata">Notifications metadata</a>.</p>

href="#NotificationsMetadata">Notifications metadata</a>.</p>

<h3 id="NotificationsMetadata">Notifications metadata</h3>

<p>The L Developer Preview uses metadata associated with your app notifications

<h3 id="DirectorySelection">Directory selection</h3>

<p>The L Developer Preview extends the <a href="{@docRoot}guide/topics/providers/document-provider.html">Storage Access Framework</a> to let users

select an entire directory, rather than individual files, to give your app

read/write access to media files. When a directory is selected, your app also

has access to all its child directories and content.</p>

<p>The L Developer Preview extends the <a href="{@docRoot}guide/topics/providers/document-provider.html">Storage Access Framework</a> to let users select an entire directory, rather than individual files, to

give your app read/write access to media files. When a directory is selected,

your app also has access to all its child directories and content.</p>

<p>To get the absolute paths to directories on external storage devices where

applications can store media files, call the new

permanent part of the device, and includes emulated external storage and

physical media slots such as SD cards in battery compartments.</p>

<p>You can bring up a system UI to allow the user to pick a directory subtree.

To do so, send  {@code android.intent.action.OPEN_DOCUMENT_TREE} in an

{@link android.content.Intent}. If the call is successful, the system displays

the {@link android.provider.DocumentsProvider} instances installed on the

device for the user to select. When the user selects a directory from this UI,

the system returns a URI representing the selected directory tree.</p>

<p>If you want to access a document in an existing directory, call the

{@code android.provider.DocumentsContract.buildDocumentViaUri()} method.

Pass the method a URI representing the path to the parent directory, and the

asynchronously at a later time or under specified conditions (such as when the

device is charging). This is useful in such situations as:</p>

<ul>

  <li>The app has non-user-facing work that you want to defer until the unit is

    plugged in.</li>

  <li>The app has a task that requires network access (or requires a wifi

  <li>The app has non-user-facing work that you can defer.</li>

  <li>The app has work you'd prefer to do when the unit is plugged in.</li>

  <li>The app has a task that requires network access (or requires a Wi-Fi

    connection).</li>

  <li>The app has a number of tasks that you want to run as a batch on a regular

   schedule.</li>

  <li>The device is charging</li>

  <li>The device is connected to an unmetered network</li>

  <li>The system deems the device to be idle</li>

  <li>Completion with a minimum delay or within a specific deadline.</li>

</ul>

<p>For example, you can add code like this to run your task on an

jobScheduler.schedule(uploadTask);

</pre>

<h3 id="PowerMeasurementTools">Developer tools and APIs for power measurement</h3>

<h3 id="PowerMeasurementTools">Developer tools for power measurement</h3>

<p>The L Developer Preview provides several new developer tools and APIs to help

you better measure and understand your app's power usage.</p>

<img src="images/battery_historian.png"

     srcset="images/battery_historian@2x.png 2x"

    alt="" width="440" height="240"

    id="figure1" />

    id="figure2" />

<p class="img-caption">

  <strong>Figure 1.</strong>HTML visualization generated by the Battery

  <strong>Figure 2.</strong>HTML visualization generated by the Battery

      Historian tool.

</p>

<div class="figure" style="width:360px">

  <img src="images/managed_apps_launcher.png"

    srcset="images/managed_apps_launcher@2x.png 2x"

    alt="" width="360" height="572" id="figure2" />

    alt="" width="360" height="572" id="figure3" />

  <p class="img-caption">

    <strong>Figure 2.</strong> Launcher screen showing managed apps (marked with

    <strong>Figure 3.</strong> Launcher screen showing managed apps (marked with

    a lock badge)

  </p>

</div>

the managed apps visually prominent by appending a “work” badge to the icon

drawable with {@code android.os.UserManager.getBadgeDrawableForUser()}.</p>

<h3 id="LockToAppMode">Lock-to-App mode</h3>

<p>The L Developer Preview introduces a new <em>Lock-to-App</em> mode that

lets you temporarily restrict users from leaving your app or being interrupted

by notifications. Once your app activates this mode, users will not be able to

see notifications, access other apps, or return to the Home screen, until your

app exits the mode.</p>

<p>To prevent unauthorized usage, the device on which you want to activate

this mode must have managed profiles or must be fully controlled by a device administrator (see <a href="#ManagedProvisioning">Managed Provisioning</a> for more information). Furthermore, the device or managed profile owner must

authorize apps to use this mode by calling {@code android.app.admin.DevicePolicyManager.setLockTaskComponents()}.</p>

<p>Before activating this mode in your app, verify that your activity is authorized by calling {@code DevicePolicyManager.isLockTaskPermitted()}.</p>

<p>To activate <em>Lock-to-App</em> mode, call

{@code android.app.Activity.startLockTask()} from your authorized activity.</p>

<p>When <em>Lock-to-App</em> mode is active, the following behavior takes

effect:</p>

<ul>

<li>The status bar is blank, and user notifications and status information is hidden.</li>

<li>The Home and Recent Apps button is hidden.</li>

<li>Other apps may not launch new activities.</li>

<li>The current app may start new activities, as long as doing so does not

create new tasks.</li>

</ul>

<p>The device will remain in this mode until an authorized activity calls

{@code Activity.stopLockTask()}.

<h2 id="Printing">Printing Framework</h2>

<h3 id="PDFRender">Render PDF as bitmap</h3>

obtain a page for rendering with {@code openPage()}, then call {@code render()}

to turn the opened {@code PdfRenderer.Page} into a bitmap. You can also set

additional parameters if you only want to convert a portion of the document into

a bitmap image (for example, to implement <a href="http://en.wikipedia.org/wiki/Tiled_rendering">tile rendering</a> in order to zoom in on the document).</p>

a bitmap image (for example, to implement <a href="http://en.wikipedia.org/wiki/Tiled_rendering">tiled rendering</a> in order to zoom in on the document).</p>

<h2 id="TestingA11y">Testing &amp; Accessibility </h2>

<ul>

<li>{@code FEATURE_LEANBACK}. Declares that your app must be installed only on

devices that support the <a href="{@docRoot}training/tv}">Android TV</a> user

interface. Example:

devices that support the <a href="{@docRoot}training/tv/index.html}">Android TV</a>user interface. Example:

<pre>

<uses-feature android:name="android.software.leanback"

              android:required="true" />