This lesson teaches you to
You should also read
- Notifications API Guide
- Intents and Intent Filters
- Notifications Design Guide
When you need to issue a notification multiple times for the same type of event, you should avoid making a completely new notification. Instead, you should consider updating a previous notification, either by changing some of its values or by adding to it, or both.
The following section describes how to update notifications and also how to remove them.
Modify a Notification
To set up a notification so it can be updated, issue it with a notification ID by
calling NotificationManager.notify(ID, notification)
. To update this notification once you've issued
it, update or create a NotificationCompat.Builder
object,
build a Notification
object from it, and issue the
Notification
with the same ID you used previously.
The following snippet demonstrates a notification that is updated to reflect the number of events that have occurred. It stacks the notification, showing a summary:
mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE); // Sets an ID for the notification, so it can be updated int notifyID = 1; mNotifyBuilder = new NotificationCompat.Builder(this) .setContentTitle("New Message") .setContentText("You've received new messages.") .setSmallIcon(R.drawable.ic_notify_status) numMessages = 0; // Start of a loop that processes data and then notifies the user ... mNotifyBuilder.setContentText(currentText) .setNumber(++numMessages); // Because the ID remains unchanged, the existing notification is // updated. mNotificationManager.notify( notifyID, mNotifyBuilder.build()); ...
Remove Notifications
Notifications remain visible until one of the following happens:
- The user dismisses the notification either individually or by using "Clear All" (if the notification can be cleared).
-
The user touches the notification, and you called
setAutoCancel()
when you created the notification. -
You call
cancel()
for a specific notification ID. This method also deletes ongoing notifications. -
You call
cancelAll()
, which removes all of the notifications you previously issued.