It’s hard to believe that it’s already been 3 years since the Apple Watch was first announced to the public. We’ve seen a multitude of changes throughout its short history and are still imagining what the future is for the “most personal product Apple has ever made.” In this session we’ll walk through the Apple Watch’s brief history, discuss the evolution the product has made in its short lifespan and what developers can do to make the most out of it’s most personal attributes. From tips and tricks for Watch Connectivity to lessons learned from implementing ClockKit, we’ll cover an array of Watch specific APIs. At the end, we’ll take a look at upcoming changes in watchOS 4, as well as take a deep dive into what needs to be done to upgrade from previous watchOS versions to support the latest one.

1. @kristinathai kristina.io
APPLE WATCH IN-DEPTH
KRISTINA THAI

2. SEPTEMBER 9, 2014

3. @kristinathai kristina.io
IT’S THE MOST PERSONAL PRODUCT
WE’VE EVER MADE
Tim Cook
APPLE WATCH UNVEILING

4. APRIL 24, 2015

5. @kristinathai kristina.io
http://www.businessinsider.com/apple-watch-demand-original-iphone-2015-6

6. @kristinathai kristina.io
http://www.cultofmac.com/323926/worlds-most-spoiled-dog-scores-two-apple-watch-editions/

7. NOVEMBER 2014

8. @kristinathai kristina.io
JOURNEY THROUGH THE LAST 2 1/2 YEARS
TRENDS TO LOOK OUT FOR
▸ Communication/Data transfer
▸ Watch apps
▸ Interaction style

9. WatchKit
watchOS 1

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12. @kristinathai kristina.io

13. @kristinathai kristina.io
THE BEGINNING
WATCH COMMUNICATION
openParentApplication:userInfo
App Groups - NSUserDefaults
NSFileManager

14. watchOS 2

15. @kristinathai kristina.io
THE BEGINNING
WATCH COMMUNICATION
openParentApplication:userInfo
App Groups - NSUserDefaults
NSFileManager

16. WATCH CONNECTIVITY

17. @kristinathai kristina.io
WATCH CONNECTIVITY
SENDER AND RECEIVER
applicationData
⌚

18. @kristinathai kristina.io
WATCH CONNECTIVITY
SENDER AND RECEIVER
applicationDatatransferUserInfo( )
⌚

19. @kristinathai kristina.io
WATCH CONNECTIVITY
SENDER AND RECEIVER
applicationDatatransferUserInfo( ) didReceiveUserInfo( )
📲⌚
transferUserInfo( ) didReceiveUserInfo(
📲 ⌚applicationData)

20. @kristinathai kristina.io

21. @kristinathai kristina.io
WATCH CONNECTIVITY
COMMUNICATION CATEGORIES
Background transfers Interactive messaging
Information isn’t needed
immediately
Information needed
immediately
Operating system determines
the most suitable time to send
the data
Requires reachable state
Content is queued for transfer

22. @kristinathai kristina.io
WATCH CONNECTIVITY
SENDER AND RECEIVERS - BACKGROUND TRANSFERS
Data Type Sender Receiver
Dictionary
(overwrite latest data)
updateApplicationContext didReceiveApplicationContext
Dictionary
(keep all data - FIFO)
transferUserInfo didReceiveUserInfo
File,
Dictionary (metadata)
transferFile didReceiveFile

23. @kristinathai kristina.io
WATCH CONNECTIVITY
SENDER AND RECEIVERS - INTERACTIVE MESSAGING
Data Type Sender Receiver
Dictionary sendMessage didReceiveMessage
NSData sendMessageData didReceiveMessageData

24. @kristinathai kristina.io
WATCH CONNECTIVITY
BACKUP OPTIONS
Messaging Type Data Type Sender
Interactive Dictionary sendMessage
Background transfer
Dictionary
(overwrite latest data)
updateApplicationContext

25. COMPLICATIONS
CLOCKKIT

26. @kristinathai kristina.io

27. @kristinathai kristina.io
https://theswiftdev.com/2016/04/28/clockkit-complications-cheat-sheet/
CLKComplicationTemplate

28. @kristinathai kristina.io
import ClockKit
class ComplicationController: NSObject, CLKComplicationDataSource {
// MARK: - Timeline Configuration
func getSupportedTimeTravelDirections(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTimeTravelDirections) -> Void) {
handler([.forward, .backward])
}
func getTimelineStartDate(for complication: CLKComplication, withHandler handler: @escaping (Date?) -> Void) {
handler(nil)
}
func getTimelineEndDate(for complication: CLKComplication, withHandler handler: @escaping (Date?) -> Void) {
handler(nil)
}
func getPrivacyBehavior(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationPrivacyBehavior) -> Void) {
handler(.showOnLockScreen)
}
// MARK: - Timeline Population
func getCurrentTimelineEntry(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTimelineEntry?) -> Void) {
// Call the handler with the current timeline entry
handler(nil)
}
func getTimelineEntries(for complication: CLKComplication, before date: Date, limit: Int, withHandler handler: @escaping ([CLKComplicationTimelineEntry]?) -> Void) {
// Call the handler with the timeline entries prior to the given date
handler(nil)
}
func getTimelineEntries(for complication: CLKComplication, after date: Date, limit: Int, withHandler handler: @escaping ([CLKComplicationTimelineEntry]?) -> Void) {
// Call the handler with the timeline entries after to the given date
handler(nil)
}
// MARK: - Placeholder Templates
func getLocalizableSampleTemplate(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTemplate?) -> Void) {
// This method will be called once per supported complication, and the results will be cached
handler(nil)
}
}

29. @kristinathai kristina.io
https://xkcd.com/1425/

30. @kristinathai kristina.io

31. @kristinathai kristina.io

32. @kristinathai kristina.io
import ClockKit
class ComplicationController: NSObject, CLKComplicationDataSource {
// MARK: - Timeline Configuration
func getSupportedTimeTravelDirections(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTimeTravelDirections) -> Void) {
handler([.forward, .backward])
}
func getTimelineStartDate(for complication: CLKComplication, withHandler handler: @escaping (Date?) -> Void) {
handler(nil)
}
func getTimelineEndDate(for complication: CLKComplication, withHandler handler: @escaping (Date?) -> Void) {
handler(nil)
}
func getPrivacyBehavior(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationPrivacyBehavior) -> Void) {
handler(.showOnLockScreen)
}
// MARK: - Timeline Population
func getCurrentTimelineEntry(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTimelineEntry?) -> Void) {
// Call the handler with the current timeline entry
handler(nil)
}
func getTimelineEntries(for complication: CLKComplication, before date: Date, limit: Int, withHandler handler: @escaping ([CLKComplicationTimelineEntry]?) -> Void) {
// Call the handler with the timeline entries prior to the given date
handler(nil)
}
func getTimelineEntries(for complication: CLKComplication, after date: Date, limit: Int, withHandler handler: @escaping ([CLKComplicationTimelineEntry]?) -> Void) {
// Call the handler with the timeline entries after to the given date
handler(nil)
}
// MARK: - Placeholder Templates
func getLocalizableSampleTemplate(for complication: CLKComplication, withHandler handler: @escaping (CLKComplicationTemplate?) -> Void) {
// This method will be called once per supported complication, and the results will be cached
handler(nil)
}
}

33. @kristinathai kristina.io
func getCurrentTimelineEntry(for complication: CLKComplication,
withHandlerhandler: @escaping (CLKComplicationTimelineEntry?) -> Void) {
// Call the handler with the current timeline entry
handler(nil)
}

34. watchOS 3

35. ACTIONABLE
RESPONSIVE
GLANCEABLE

36. ACTIONABLE RESPONSIVEGLANCEABLE

37. @kristinathai kristina.io

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39. BACKGROUND TASKS

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41. @kristinathai kristina.io
BACKGROUND TASKS
WKApplicationRefreshBackgroundTask⌚
WKSnapshotRefreshBackgroundTask📷
WKWatchConnectivityRefreshBackgroundTask📲
WKURLSessionRefreshBackgroundTask🌐

42. @kristinathai kristina.io
WKApplicationRefreshBackgroundTask⌚
⌚ 🌐⌚
NSURLSession
📷⌚
Snapshots
Update app from background

43. @kristinathai kristina.io
WKSnapshotRefreshBackgroundTask📷
Make updates to your app’s UI
Supporting up-to-date snapshots keeps your users informed

44. @kristinathai kristina.io
WKURLSessionRefreshBackgroundTask🌐
🌐⌚Trigger NSURLSession to update app from background

45. @kristinathai kristina.io
WKWatchConnectivityRefreshBackgroundTask📲
📱⌚Get latest data from iPhone via Watch Connectivity
📱⌚
Be a good battery/data citizen by pulling data from server only once
🌐

46. watchOS 4

47. @kristinathai kristina.io
SIERRA HIGH SIERRA
WATCHOS 3 WATCHOS 4

48. @kristinathai kristina.io
FRONTMOST WATCH STATE

49. @kristinathai kristina.io
WATCHOS 4
FRONTMOST WATCH STATE
▸ Time on screen defaults to 2 minutes, can extend to 8 minutes
▸ Play haptics
▸ Customize UI when receiving notifications
▸ Enhancements for Watch Connectivity & NSURLSession

50. @kristinathai kristina.io
BACKGROUND TASKS
Location🌎
In-Line Audio Recording🎤
WATCHOS 4

51. @kristinathai kristina.io
WATCHOS 4
MISCELLANEOUS
▸ Major improvements to performance right out of the box
▸ Dock has both favorites and recents mode
▸ Can overlap UI elements now
▸ Screen autorotation
▸ SpriteKit/SceneKit can take up the entire watch screen
▸ CoreBluetooth now supported
▸ Combined API for completing background task & snapshotting

52. Demo

53. What’s next?

54. @kristinathai kristina.io
http://techiewheels.com/technology/google-maps-amazon-ebay-ditched-apple-watch/

55. @kristinathai kristina.io

56. @kristinathai kristina.io
THEY'RE LIKE DIET VERSIONS OF THE
FULL SMARTPHONE APP, AND THEY
MAKE NO SENSE ON THE WATCH.
Steve Kovach
“APPLE WATCH APPS ARE BAD” - BUSINESS INSIDER
businessinsider.com/apple-watch-apps-are-bad-2015-5

57. @kristinathai kristina.io
http://www.cnbc.com/2017/05/05/apple-watch-fitbit-shipments-market-share-q1-2017.html

58. @kristinathai kristina.io

59. THANKS!
@kristinathai
me@kristina.io
kristina.io