1. 1. Notification channel groups

• Notification channels let us bundle together notification channels
• Beneficial where we find ourselves using the same notification channels in several places in our app.
• Example use case:
• our app supports both a personal account and a business account
• both account types have identical notification channels;
• A personal user account including 2 notification channels:
• Notifications of new comments on your posts.
• Notifications recommending posts by your contacts.
• A business user account including 2 notification channels:
• Notifications of new comments on your posts.
• Notifications recommending posts by your contacts.
• In the above use case it makes sense to use notification channel groups
• To create a notification channel group:

```java
// The id of the group.
String group = "my_group_01";

// The user-visible name of the group.
CharSequence name = getString(R.string.group_name);

NotificationManager mNotificationManager =
(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

mNotificationManager.createNotificationChannelGroup(new NotificationChannelGroup(group, name));
```

• Once you've created a new group you can call `setGroup()` to associate a new channel with the group.
• You can only modify the association between notification channel and group before you submit the channel to the notification manager.

• To create a batch of notification groups by using the `createNotificationChannelGroups()` method, we can pass in a List of NotificationChannelGroup instances for the groups we wish to create:

```java
NotificationManager notificationManager =
(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

List<NotificationChannelGroup> notificationChannelGroups = new ArrayList();
notificationChannelGroups.add(new NotificationChannelGroup("group_one", "Group One"));
notificationChannelGroups.add(new NotificationChannelGroup("group_two", "Group Two"));
notificationChannelGroups.add(new NotificationChannelGroup("group_three", "Group Three"));

notificationManager.createNotificationChannelGroup(notificationChannelGroups);
```