Merge "docs: Adding docs for N preview Picture-in-picture" into mnc-mr-docs

page.title=Picture-in-picture

page.keywords=preview,sdk,PIP,Picture-in-picture

page.tags=androidn

@jd:body

<div id="tb-wrapper">

<div id="tb">

  <h2>In this document</h2>

  <ol>

    <li><a href="#declaring">Declaring Your Activity Supports

    Picture-in-picture</a></li>

    <li><a href="#pip_button">Switching Your Activity to Picture-in-picture</a>

    </li>

    <li><a href="#handling_ui">Handling UI During Picture-in-picture</a>

    </li>

    <li><a href="#continuing_playback">Continuing Video Playback While in

Picture-in-picture</a></li>

    <li><a href="#best">Best Practices</a></li>

  </ol>

</div>

</div>

<p>In the Android N Developer Preview, Android TV users can now watch a video

in a pinned window in a corner of the screen when navigating within

applications. This new Picture-in-picture (PIP) mode lets apps run a video

activity in the pinned window while another activity continues in the

background. The PIP window lets users multi-task while using your app, making

browsing and exploring your app easier and more engaging.</p>

<p>Your app can decide when to trigger PIP mode. Here are some examples on

when to enter PIP mode:</p>

<ul>

<li>When the user is navigating back from a video, the video activity can be

placed in PIP mode instead of being closed.</li>

<li>When the user is watching the end of an episode of content, the video can

be placed in PIP mode while the main screen displays promotional or summary

information about the next episode in the series.</li>

<li>When the user wants to queue up additional content to watch while watching

the currently playing content, the video can be placed in PIP mode and a

content selection activity can be shown in the main screen.</li>

</ul>

<p>The PIP window is 240 x 135 dp and is shown at the top-most layer in one of

the four corners of the screen, chosen by the system. The user can bring up a

PIP menu that lets them toggle the PIP window to full screen, or close the PIP

window, by holding down the <b>Home</b> button on the remote. If another

video starts playing on the main screen, or the user leaves the app, the PIP

window is automatically closed.</p>

<p>PIP leverages the multi-window APIs available in the N Developer Preview to

provide the pinned video overlay window. To add PIP to your app, you need to

register your activities that support PIP, switch your activity to PIP mode as

needed, and make sure UI elements are hidden and video playback continues when

the activity is in PIP mode.</p>

<h2 id="declaring">Declaring Your Activity Supports Picture-in-picture</h2>

<p>By default, the system will not automatically support PIP for applications.

If you want support PIP in your application, you need to register your video

activity in your manifest by setting

<code>android:supportsPictureInPicture</code> and

<code>android:resizeableActivity</code> to <code>true</code>. Also, specify

that your activity handles layout configuration changes so that your activity

won't relaunch when layout changes occur during PIP mode transitions.</p>

<pre>

<activity android:name="VideoActivity"

    android:resizeableActivity="true"

    android:supportsPictureInPicture="true"

    android:configChanges=

        "screenSize|smallestScreenSize|screenLayout|orientation"

    ...

</pre>

<p>When registering your activity, keep in mind that in PIP mode, your

activity is shown in a small overlay window on a TV screen. Video playback

activities with minimal UI provide the best user experience. Non-video

activities with detailed UI may not provide a good user experience in PIP

mode.</p>

<h2 id="pip_button">Switching Your Activity to Picture-in-picture</h2>

When you need to switch your activity into PIP mode, call

<code>Activity.enterPictureInPicture()</code>. The following example switches

to PIP mode when the user selects a dedicated PIP button on a media control

bar:</p>

<pre>

@Override

public void onActionClicked(Action action) {

    if (action.getId() == R.id.lb_control_picture_in_picture) {

        getActivity().enterPictureInPicture();

        return;

    }

    ...

</pre>

<p>Adding a PIP button to your media control bar lets your user easily switch

to PIP mode while controlling video playback.</p>

<img src="{@docRoot}preview/images/pip-button.png" />

<p class="img-caption"><strong>Figure 1.</strong> A Picture-in-picture

button on a media control bar.</p>

<p>A new <code>PlaybackControlsRow.PictureInPictureAction</code> class is

provided to use the PIP icon and handle control bar PIP actions.</p>

<h2 id="handling_ui">Handling UI During Picture-in-picture</h2>

<p>When your activity enters PIP mode, your activity should only show video

playback. You should remove UI elements before your activity enters PIP,

and restore these elements when your activity becomes full-screen again.

Override <code>Activity.onPictureInPictureChanged()</code> or

<code>Fragment.onPictureInPictureChanged()</code> and enable or

disable your UI elements as needed, for example:</p>

<pre>

@Override

public void onPictureInPictureChanged(boolean inPictureInPicture) {

    if (inPictureInPicture) {

        // Hide the controls in picture-in-picture mode.

        ...

    } else {

        // Restore the playback UI based on the playback status.

        ...

    }

}

</pre>

<h2 id="continuing_playback">Continuing Video Playback While in

Picture-in-picture</h2>

<p>When your activity switches to PIP, the system considers the activity in a

paused state, and calls your activity's <code>onPause()</code> method. Video

playback should not be paused and should continue playing if the activity is

paused due to PIP mode. Check for PIP in your activity's

<code>onPause()</code> method and handle playback appropriately, for

example:</p>

<pre>

@Override

public void onPause() {

    // If called due to PIP, do not pause playback

    if (inPictureInPicture()) {

        // Continue playback

        ...

    }

    // If paused but not in PIP, pause playback if necessary

    ...

}

</pre>

<p>When your activity switches out of PIP mode back to full screen mode, the

system resumes your activity and calls your <code>onResume()</code> method.</p>

<h2 id="best">Best Practices</h2>

<p>PIP is intended for activities that play full-screen video. When switching

your activity into PIP mode, avoid showing anything except video content.

Track when your activity enters PIP mode and hide UI elements, as described

in <a href="#handling_ui">Handling UI During Picture-in-picture Mode</a>.</p>

<p>Since the PIP window is shown as a floating window in the corner of the

screen, you should avoid showing critical information in the main screen

in any area that can be obscured by the PIP window.</p>

<p>When an activity is in PIP mode, by default it doesn't get input focus. To

receive input events while in PIP mode, use

<code>MediaSession.setMediaButtonReceiver()</code>.</p>

<p>For more information on multi-window APIs, see

<a href="{@docRoot}preview/features/multi-window.html">Android N 

Developer Preview Multi-Window Support</a>.</p>