Передача состояния с iPhone на Apple Watch

State transfer from iPhone to Apple Watch

Artemiy Sobolev Software Developer, Parallels Inc.

Agenda

• Parallels Access for Apple Watch

• Architecture design goals

• Living objects tree

• How can it be better with watchOS 2

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Parallels Access

• Simple yet powerful remote client with great usability

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Parallels Access for Apple Watch:

Usability scenarios

• Checkout computers’ availability

• Connect/Disconnect

• Media control

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iOS 8 and watchOS 1

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iOS 8 and watchOS 1

Parent applicationWatchKit extension

App Store

WatchKit app

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iOS 8 and watchOS 1

Parent applicationWatchKit extension

App Store

WatchKit app

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iOS 8 and watchOS 1

Parent application

WatchKit extension

App Store

WatchKit app

Parent application

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Architecture design goals

• Reduce dependency for core components

• Delta updates

• Transfer changes from iPhone to Watch at any time

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Live objects tree abstraction

Process A,

Machine aProcess B,

Machine b

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Process A,

Machine aProcess B,

Machine b

Live objects tree abstraction

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Process A,

Machine aProcess B,

Machine b

Live objects tree abstraction

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Process A,

Machine aProcess B,

Machine b

Live objects tree abstraction

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Process A,

Machine aProcess B,

Machine b

Live objects tree abstraction

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Process A,

Machine aProcess B,

Machine bProcess C,

Machine c

Live objects tree abstraction

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Process A,

Machine aProcess B,

Machine bProcess C,

Machine c

Live objects tree abstraction

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Process A,

Machine aProcess B,

Machine bProcess C,

Machine c

Live objects tree abstraction

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Process A,

Machine aProcess B,

Machine bProcess C,

Machine c

Live objects tree abstraction

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Parallels Access application

Parallels Access extension

Live objects tree abstraction

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Parallels Access application

Watch app architecture

•No delegates

•No notifications

•KVO only

•Special ViewModels

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How we achieve this sync mechanism

• Reliable iCloud sync mechanism:

• NSFileCoordinator

• NSFilePresenter

• File wrappers

• NSCoding

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Turning on App Groups capability

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NSFileCoordinator + NSFilePresenter

«Don’t implement NSFilePresenter on your own»

- Dave Delong on StackOverflow

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NSFileCoordinator

• Initialized for each file operation

• Coordinates file reading and writing

• Not async

• Contains list of coordination methods

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NSFilePresenter Protocol

• Required properties:

presentedItemURL: NSURL

presentedItemOperationQueue: NSOperationQueue

• To add/remove file presenter call:

NSFileCoordinator.addFilePresenter(…)

NSFileCoordinator.removeFilePresenter(…)

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NSFilePresenter callbacks

• presentedItemDidChange

• presentedItemDidMoveToURL:

• presentedItemDidGainVersion:

• presentedItemDidLoseVersion:

• presentedItemDidResolveConflictVersion:

• NSFileVersion

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File Wrappers

Xcode.app

ContentsMacOSXcode

• Directory with extension

• Helps isolate content

• All apps and frameworks are file wrappers

27

File Wrappers + File Presenter

<host id>.paxhost

hostInfo.plist

img.png

• File Presenter can present directory

• The same callbacks:

presentedItem -> presentedSubitem

• All callbacks in one place

• Diminishes the need to merge changes

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Things to consider

• Requires minimum 3 queues

• System holds strong references to file presenters

• Memory limit for extension is ~10 MB

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watchOS 2

Watch Connectivity

Parent Application

extension

• WCSession with the Delegate

• File Transfer

• Application context

• Interactive Messaging

• User info

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Other uses of approach

• The same mechanism with WCSession’s file transfer

• Sync state between

• iOS devices and Macs via iCloud

• iOS application and extension

• 2 iOS applications

• 2 different Mac applications

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State transfer from iPhone to Apple Watch

Artemiy Sobolev

asobolev@parallels.com

Software Developer, Parallels Inc. c

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