Notifications. Alexander Nelson September 26, University of Arkansas - Department of Computer Science and Computer Engineering

Transcription

1 Notifications Alexander Nelson September 26, 2017 University of Arkansas - Department of Computer Science and Computer Engineering

2 Reminders

3 Projects Project 2 is out! Due Friday October 6th Final Project Report 2 due Friday Create a (temporary) App Name Make your title be AppName: Longer Description of Application

4 Notifications

5 Notifications A notification is a message which is displayed to the user outside of the normal User Interface These slides are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

6 Notifications When a notification is issued, it appears in the notification area To see details, a user may open the notification drawer Both the notification area and drawer are system controlled, and the user may view them at any time

7 Notification Design Notifications have their own design style guide: material.io/guidelines/patterns/notifications.html This guide has a lot of really good information from a UI design perspective that can be consulted

8 Creating a Notification UI information and actions are determined in a NotifiactionCompat.Builder object Created using the Builder.build() function, which returns a Notification object with the specifications Issued using the NotificationManager.notify() method

9 Required Contents A notification must contain the following: setsmallicon() sets the small icon setcontenttitle() Title for the notification setcontenttext() sets the detail text setchannelid() set a channel (for API 26 and above)

10 Optional Notification Contents Action Allow directly placing the user in the Activity that the notification addresses Defined by a PendingIntent that starts an Activity If not the home screen, create an artificial back stack Click Behavior Associate a PendingIntent with a click/swipe behavior Set click behavior with setcontentintent() Set swipe or delete notification with setdeleteintent()

11 Notification priority setpriority() Takes one of 5 priority constants PRIORITY MIN (-2) PRIORITY MAX 2 Default is 0 Deprecated in API 26 (Oreo) in favor of channels

12 Optional Notification Contents Sounds setsound() Color setcolorized() - should only be used for high priority ongoing tasks setfullscreenintent() Can be used to directly launch app. Very disruptive if not needed setlights() Used to manipulate LED on device More on reference page for NotificationCompat.Builder

13 Build Simple Notification Create explicit intent for the activity ResultActivity.class.setChannelId() for API 26 and later

14 Build Simple Notification Create artificial back stack navigating to the correct activity.setcontentintent() chooses the click action

15 Build Simple Notification Get instance of the Notification Manager.build() builds the notification from the Builder object NotificationManager instance s.notify() method shows the notification

16 Expanded Layouts You may want to use larger notifications for specific purposes The following table describes a few: Style BigPictureStyle BigTextStyle DecoratedCustomViewStyle InboxStyle Description Notifications that include a large image attachment Notifications that include a lot of text Custom views that are decorated by the system Nnotifications that include a list of (up to 5) strings More at android/support/v4/app/notificationcompat.style.html

17 Updating a Notification Often better to update an existing notification rather than issue a new one To update, issue notifications using the same notification ID If a notification exists with that ID, the notification is updated

18 Updating a Notification Android limits the rate at which notifications may be updated Posting updates too frequently can result in dropped notifications setonlyalertonce() Allow providing sound/vibrate/ticker for notifications on just the original notification, not updates

19 Updating a Notification

20 Removing a Notification Notifications remain visible until: User dismisses the notification (individually or clear all) User clicks notification, and setautocancel() is specified for notification cancel() is called for the notification ID cancelall() is called, removing all notifications issued by the application settimeoutafter() System cancels notification after a duration elapses

21 Preserving Navigation When an activity is started from a notification, you should consider the user s expected experience e.g. If you start a second layer activity, pressing back should return to the main application activity Two general situations: Regular Activity, Special Activity

22 Regular Activity If starting activity that is part of App s normal workflow: set PendingIntent() to start fresh task provide PendingIntent() with back stack reproducing the normal back behavior

23 Setting up Regular Activity PendingIntent To provoide a PendingIntent that starts a direct Activity: 1. Define Activity hierarchy in manifest 2. Create back stack based on the Intent that starts the Activity

24 Defining Hierarchy For Android and lower: Specify parent by adding a <meta-data> Parameters are: android:name= android.support.parent ACTIVITY android:value=.mainactivity For Android 4.1 and later: Add android:parentactivityname tag

25 Create back stack To create the back stack for the activity Create the Intent to start the Activity Create a stack builder object Add back stack to stack builder by calling addparentstack() Add the Intent that starts the Activity with addnextintent() Add any arguments to the Intent objects with.editintentat() Get a PendingIntent for the backstack by calling getpendingintent()

26 Example Create Back Stack

27 Special Activity For an Activity that only occurs through a notification, it doesn t make sense to return to the application In this case, pressing back should return to the Home screen

28 Set up Special Activity PendingIntent Special Activity doesn t need a back stack No need to define its parent in the manifest Instead, get PendingIntent by calling getactivity()

29 Special Activity Manifest Special parameters: android:launchmode= singletask android:taskaffinity= android:excludefromrecents= true These three make sure that the activity is launched and not the default, and that it wont show up in the recent applications so user can t navigate back to the special activity

30 Build and Issue Notification To build the notification: 1. Create an Intent to start the Activity 2. Set the Activity to start in a new, empty task, by calling setflags() with: FLAG ACTIVITY NEW TASK FLAG ACTIVITY CLEAR TASK 3. Set any other options 4. Create PendingIntent by calling getactivity()

31 Example Special Activity

32 Example Special Activity

33 New Notification Options

34 Reply to a Notification API level 24 (Nougat) and higher Users can respond directly to notifications inside the dialog using inline actions

35 Add Inline Reply Action To enable this behavior: 1. Create instance of RemoteInput.Builder 2. Attach RemoteInput object to an action with addremoteinput() 3. Apply the action to a notification and issue the notification

36 Retrieve user input from Inline Reply If user chooses reply action, you get the reply by: 1. getresultsfromintent(intent) Returns a Bundle that contains the text response 2. Query the bundle using the result key 3. Build and issue another notification to show that reply action succeeded

37 Bundling Notifications Also API 24 (Nougat), notifications may be bundled to represent a queue of notifications Use Bulder.setGroup() to bundle similar notifications

38 Bundling Notifications These notification groups provide a parent notification, which may be expanded to show child notifications These child notifications may in turn be expanded to show its entire content If the same app sends four or more notification with no group, Android will automatically bundle them

39 When to Bundle Bundle notifications if the following are true: Child notifications are complete notifications Can be displayed without need of group summary There is a benefit to surfacing the child notification, e.g. They are actionable, and actions are specific to a child There is more information to the child that may need to be read

40 Badges In supported launchers running on devices of Android 8.0 (API 26: Oreo), apps may: Display notification badges on app icons Long-press on app icon to glance at notifications associated with a badge Our phones do not support Android 8.0. You may use an emulator to test this behavior

41 Notification Channels Starting with Android 8.0, notification channels allow creation of user-customizable channel for each type of notification Allows user specification of channels to determine how a notification is shown