1page.title=Stacking Notifications
2page.tags=notifications
3helpoutsWidget=true
4
5@jd:body
6
7<div id="tb-wrapper">
8<div id="tb">
9
10<h2>This lesson teaches you to</h2>
11<ol>
12  <li><a href="#AddGroup">Add Each Notification to a Group</a></li>
13  <li><a href="#AddSummary">Add a Summary Notification</a></li>
14</ol>
15
16</div>
17</div>
18<img src="/wear/images/11_bundles_B.png" height="200" width="169"
19    style="margin:0 0 20px 20px; clear:both; float:right" alt="">
20<img src="/wear/images/11_bundles_A.png" height="200" width="169"
21    style="margin:0 20px 20px 20px; float:right" alt="">
22<p>When creating notifications for a handheld device, you should always aggregate similar
23notifications into a single summary notification. For example, if your app creates notifications
24for received messages, you should not show more than one notification
25on a handheld device&mdash;when more than one is message is received, use a single notification
26to provide a summary such as "2 new messages."</p>
27
28<p>However, a summary notification is less useful on an Android wearable because users
29are not able to read details from each message on the wearable (they must open your app on the
30handheld to view more information). So for the wearable device, you should
31group all the notifications together in a stack. The stack of notifications appears as a single
32card, which users can expand to view the details from each notification separately. The new
33{@link android.support.v4.app.NotificationCompat.Builder#setGroup setGroup()} method makes this
34possible while allowing you to still provide only one summary notification on the handheld device.</p>
35
36<h2 id="AddGroup" style="clear:right">Add Each Notification to a Group</h2>
37
38<p>To create a stack, call {@link android.support.v4.app.NotificationCompat.Builder#setGroup setGroup()}
39for each notification you want in the stack and specify a
40group key. Then call {@link android.support.v4.app.NotificationManagerCompat#notify notify()}
41to send it to the wearable.</p>
42
43<pre style="clear:right">
44final static String GROUP_KEY_EMAILS = "group_key_emails";
45
46// Build the notification, setting the group appropriately
47Notification notif = new NotificationCompat.Builder(mContext)
48         .setContentTitle("New mail from " + sender1)
49         .setContentText(subject1)
50         .setSmallIcon(R.drawable.new_mail)
51         .setGroup(GROUP_KEY_EMAILS)
52         .build();
53
54// Issue the notification
55NotificationManagerCompat notificationManager =
56        NotificationManagerCompat.from(this);
57notificationManager.notify(notificationId1, notif);
58</pre>
59
60<p>Later on, when you create another notification, specify
61the same group key. When you call
62{@link android.support.v4.app.NotificationManagerCompat#notify notify()},
63this notification appears in the same stack as the previous notification,
64instead of as a new card:</p>
65
66<pre style="clear:right">
67Notification notif2 = new NotificationCompat.Builder(mContext)
68         .setContentTitle("New mail from " + sender2)
69         .setContentText(subject2)
70         .setSmallIcon(R.drawable.new_mail)
71         .setGroup(GROUP_KEY_EMAILS)
72         .build();
73
74notificationManager.notify(notificationId2, notif2);
75</pre>
76
77<p>By default, notifications appear in the order in which you added them, with the most recent
78  notification visible at the top.  You can order notifications in another fashion by calling
79  {@link android.support.v4.app.NotificationCompat.Builder#setSortKey setSortKey()}.</p>
80
81
82<h2 id="AddSummary">Add a Summary Notification</h2>
83
84<img src="{@docRoot}wear/images/notif_summary_framed.png" height="242" width="330" style="float:right;margin:0 0 20px 40px" alt="" />
85
86<p>It's important that you still provide a summary notification that appears on handheld devices.
87So in addition to adding each unique notification to the same stack group, also add a summary
88notification and call {@link android.support.v4.app.NotificationCompat.Builder#setGroupSummary setGroupSummary()}
89on the summary notification.</p>
90
91<p>This notification does not appear in your stack of notifications on the wearable, but
92it appears as the only notification on the handheld device.</p>
93
94<pre style="clear:right">
95Bitmap largeIcon = BitmapFactory.decodeResource(getResources(),
96        R.drawable.ic_large_icon);
97
98// Create an InboxStyle notification
99Notification summaryNotification = new NotificationCompat.Builder(mContext)
100        .setContentTitle("2 new messages")
101        .setSmallIcon(R.drawable.ic_small_icon)
102        .setLargeIcon(largeIcon)
103        .setStyle(new NotificationCompat.InboxStyle()
104                .addLine("Alex Faaborg   Check this out")
105                .addLine("Jeff Chang   Launch Party")
106                .setBigContentTitle("2 new messages")
107                .setSummaryText("johndoe@gmail.com"))
108        .setGroup(GROUP_KEY_EMAILS)
109        .setGroupSummary(true)
110        .build();
111
112notificationManager.notify(notificationId3, summaryNotification);
113</pre>
114
115<p>
116This notification uses {@link android.support.v4.app.NotificationCompat.InboxStyle},
117which gives you an easy way to create notifications for email or messaging apps.
118You can use this style, another one defined in {@link android.support.v4.app.NotificationCompat},
119or no style for the summary notification.
120</p>
121
122<p class="note"><b>Tip:</b>
123To style the text like in the example screenshot, see
124<a href="{@docRoot}guide/topics/resources/string-resource.html#StylingWithHTML">Styling
125with HTML markup</a> and
126<a href="{@docRoot}guide/topics/resources/string-resource.html#StylingWithSpannables">Styling
127with Spannables</a>.
128</p>
129
130<p>Summary notifications can also affect notifications on wearables without being displayed on them.
131When creating a summary notification, you can use the
132{@link android.support.v4.app.NotificationCompat.WearableExtender} class and call
133{@link android.support.v4.app.NotificationCompat.WearableExtender#setBackground setBackground()} or
134{@link android.support.v4.app.NotificationCompat.WearableExtender#addAction addAction()} to set
135a background image or an action that applies to the entire stack on the wearable. For instance,
136to set the background for an entire stack of notifications:
137</p>
138
139<pre>
140Bitmap background = BitmapFactory.decodeResource(getResources(),
141        R.drawable.ic_background);
142
143NotificationCompat.WearableExtender wearableExtender =
144        new NotificationCompat.WearableExtender()
145        .setBackground(background);
146
147// Create an InboxStyle notification
148Notification summaryNotificationWithBackground =
149        new NotificationCompat.Builder(mContext)
150        .setContentTitle("2 new messages")
151        ...
152        .extend(wearableExtender)
153        .setGroup(GROUP_KEY_EMAILS)
154        .setGroupSummary(true)
155        .build();
156</pre>