docs/html/wear/notifications/stacks.jd

page.title=Stacking Notifications

@jd:body

<img src="{@docRoot}wear/images/11_bundles_B.png" height="200" width="169" style="float:right;margin:0 0 20px 40px" />
<img src="{@docRoot}wear/images/11_bundles_A.png" height="200" width="169" style="float:right;margin:0 0 20px 40px" />

<p>When creating notifications for a handheld device, you should always aggregate similar
notifications into a single summary notification. For example, if your app creates notifications
for received messages, you should not show more than one notification
on a handheld device&mdash;when more than one is message is received, use a single notification
to provide a summary such as "2 new messages."</p>

<p>However, a summary notification is less useful on an Android wearable because users
are not able to read details from each message on the wearable (they must open your app on the
handheld to view more information). So for the wearable device, you should
group all the notifications together in a stack. The stack of notifications appears as a single
card, which users can expand to view the details from each notification separately. The new
<a href="{@docRoot}reference/android/preview/support/wearable/notifications/WearableNotifications.Builder.html#setGroup(java.lang.String, int)">
<code>setGroup()</code></a> method makes this possible while allowing you to still provide
only one summary notification on the handheld device.</p>

<p>For details about designing notification stacks, see the
<a href="{@docRoot}wear/design/index.html#NotificationStacks">Design Principles of Android
Wear</a>.</p>


<h2 id="AddGroup">Add Each Notification to a Group</h2>

<p>To create a stack, call <a
href="{@docRoot}reference/android/preview/support/wearable/notifications/WearableNotifications.Builder.html#setGroup(java.lang.String, int)">
<code>setGroup()</code></a> for each notification you want in the stack, passing the same
group key. For example:</p>

<pre style="clear:right">
final static String GROUP_KEY_EMAILS = "group_key_emails";

NotificationCompat.Builder builder = new NotificationCompat.Builder(mContext)
         .setContentTitle("New mail from " + sender)
         .setContentText(subject)
         .setSmallIcon(R.drawable.new_mail);

Notification notif = new WearableNotifications.Builder(builder)
         .setGroup(GROUP_KEY_EMAILS)
         .build();
</pre>

<p>By default, notifications appear in the order in which you added them, with the most recent
  notification visible at the top.  You can define a specific position in the group
  by passing an order position as the second parameter for <a
href="{@docRoot}reference/android/preview/support/wearable/notifications/WearableNotifications.Builder.html#setGroup(java.lang.String, int)">
<code>setGroup()</code></a>.</p>


<h2 id="AddSummary">Add a Summary Notification</h2>

<p>It's important that you still provide a summary notification that appears on handheld devices.
So in addition to adding each unique notification to the same stack group, also add a summary
notification, but set its order position to be <a
href="{@docRoot}reference/android/preview/support/wearable/notifications/WearableNotifications.html#GROUP_ORDER_SUMMARY"><code>GROUP_ORDER_SUMMARY</code></a>.</p>

<pre>
Notification summaryNotification = new WearableNotifications.Builder(builder)
         .setGroup(GROUP_KEY_EMAILS, WearableNotifications.GROUP_ORDER_SUMMARY)
         .build();
</pre>

<p>This notification will not appear in your stack of notifications on the wearable, but
appears as the only notification on the handheld device.

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