1. Session III – Lifecycle and More
Daryl Rudolph

2. Agenda
Application
Lifecycle
Live
Tiles, Background
Process and
Lock Screen
Implementing the
Search Contract

3. Application Lifecycle
Show the flow
Feel Connected and
Alive

4. Memory Management
User selects app for foreground
System manages app lifetime
User launches many apps
User manages app lifetime

5. App process lifetime

6. Application States
Running
SuspendedNot Running
Resuming
Activated Suspending

7. Process lifetime walkthrough

8. When do apps get terminated
• System needs more memory
• User switch occurs
• System shutdown
• Apps crash
Apps do not get notified when
they are getting terminated

9. Process state transitions
5seconds
not
User
Launche
s App
Splash
screen

10. Suspend under the hood
• Suspended apps are not scheduled by the NT Kernel
• No CPU, Disk or Network consumed
• All threads are suspended
• Apps remain in memory
• Kernel ensures apps are not suspended in critical
sections that could cause system wide deadlocks
• Apps instantly resumed from suspend when brought to
foreground

11. Interacting with your users

12. App Activation Through Contracts
• Apps are activated through contracts
• Launch, search, ShareTarget, etc.
• Apps need to initialize contract specific actions
• Context is provided
Running App
launch
shareTarget
activated
kind
search

13. App crash? Start over
• Apps that are stuck are no fun
• Your app can be terminated abruptly in any of these
cases
• Too long to load
• Too long to suspend
• Stopped handling input messages (Blocking I/O on UI thread)
• Task manager
• Bring the user back home, and ignore saved user
session state
• previousExecutionState is provided in activation event
args

14. Best practices for saving and restoring state
Scenario You should….
User is using your
App
• Save user data incrementally
App switched away
from (Suspending)
• Save where the user is – what
screen they are on, for example
Not running App
launched by user
(Activated)
• Bring the user back and restore
their session as if they never left
Suspended App
launched by user
(Resuming)
• Do nothing

15. Demo
Suspend Demo

16. Search Contract
Finding your application
Use the Right
Contracts

17. Search 1 2 3
1. Search box is scoped to the
main app on screen
2. Query suggestions provided by
the main app on screen
• Autocompletes to terms for which
the app has search results
3. List of installed Windows 8 style
apps that have implemented the
search contract

18. Query submitted
User
Show Search
results view
Show previous
search results
view
Search Pane
Submit query to
App
Search App
Query Submitted
Event

19. Demo
Search Contract Demo

20. Live tiles
Keep the action going
Invest in a Great Tile

23. Badges
• Overlays status on top of tile
• Supports square and wide tiles
• Number up to 99 or pre-defined glyph:
• Always legible on top of images
BadgeBadge

24. Notification Queuing
• By default only last notification shown
• Opt-in to automatically cycle tile through last five
notifications

25. Live Tiles things to remember
• Tiles updated using pre-defined templates
• Text-only, image-only or combination
• JPEG or PNG only, max size 150 KB
• Local, cloud or background updates
Invest in a Great Tile

26. Demo
Live Tiles

27. Secondary Tiles
• Tiles created by “pinning” content from
app
• Pin initiated by app via simple runtime
call
• User confirms pin operation via system UI
• Exposes a personalized surface for app
• Same capabilities as app tiles
• Launch leads to relevant content

28. Demo
Secondary Tiles

29. RTC – Real Time Communication apps
Keep the action going
Invest in a Great Tile

30. Review app process lifetime

31. …with RTC appsThe app lifecycle

32. Network Trigger
RTC trigger APIs
System Trigger Time Trigger
Background Task Infrastructure
VoIP IM Your App
App OS

33. Network
Trigger
System
Trigger
Time
Trigger
Background Task Infrastructure
VoIP IM Mail
Changing Live Tile
Time
Trigger
Setting up a Time Trigger

34. Live tiles with push notifications
• Tiles can be updated even if
your app is not running!
• Push notifications can be used
to remotely update a tile on
the Start screen
• Great for showing the newest
content available to your users
App Cloud Service
Windows Push
Notification Service
(WNS)
HTTP POST
Notification
Delivered

35. Push Notification Overview
Notificatio
n
Client
Platform
App Service
Windows Push
Notification
Service
POST <channel URI> HTTP/1.1
Content-Type: text/xml
Host: db3.notify.windows.com
X-WNS-Type: wns/badge
Authorization: Bearer <authentication
token>
Content-Length: 58
<?xml version="1.0" encoding="utf-8"?>
<badge value="11"/>

36. Time
Trigger
using Windows.ApplicationModel.Background;
// Specify the trigger
TimeTrigger trigger = new TimeTrigger(UpdateInterval, Periodic);
Create time
trigger
// Associate app code with the trigger
BackgroundTaskBuilder taskBuilder = new BackgroundTaskBuilder();
taskBuilder.TaskEntryPoint = “MyApp.Background.UpdateEmailTask";
taskBuilder.SetTrigger(trigger);
taskBuilder.Name = “TimerExpiry";
Associate
trigger with
app code
// Register the task for background execution
IBackgroundTaskRegistration taskRegistration =
taskBuilder.Register();
Register
trigger

37. public sealed class UpdateLiveTileTask : IBackgroundTask {
public void Run(IBackgroundTaskInstance
taskInstance)
{
// Your app code to update email
}
}
}
using Windows.ApplicationModel.Background;
Time
Trigger

38. Demo
Live Tiles /Lock
Screen/Background

39. Best Practices for Tiles
• Display new, tailored and engaging content to the user
• Keep tile fresh by updating as your app content
changes
• Reference content that lives on your app’s
home page so the user can find it easily.
• Keep content safely ignorable and glanceable - for short
messages only
• Use square size if tile is not live
• No display ads! 

40. Agenda
Application
Lifecycle
Live Tiles,
Background
Process and
Lock Screen
Implementing the
Search Contract

41. Hands-On Lab 3 OR Create your own app
Running in the background

42. Create your own app
• You can work on Hands-on Lab 3 OR Create your own
app
• You have until 4:20 PM
• Don’t have to decide if you are entering until 4:20 PM
• Presentation can be PowerPoint and/or demonstration
• Must let me know beforehand if you don’t have VGA
connection
• Each contestant will have exactly 3 minutes to present!
• Be creative. Keep in mind the traits of a great Windows
8 app!
• Note: Anyone who attended today can enter to win the
app contest sponsored by Component Art for a $10,000
grand prize, even if you don’t enter today’s contest.

43. Contact/References
• Magenic – http://www.magenic.com
• Daryl Rudolph – darylr@magenic.com
• http://dev.windows.com
• http://design.windows.com
• API Sites
• http://www.restfulwebservices.net
• http://developer.mashery.com/apis
• http://www.programmableweb.com