Software Development Done Right

See the time on your wrist

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June 4th, 2015

Lammert Westerhoff Jeroen Leenarts

Who are we?Lammert Westerhoff - iOS Developer at Xebia - Currently at NS

Jeroen Leenarts - iOS Developer at Xebia - Founder Stichting CocoaHeadsNL - Currently at ING CB

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• Introduction • Design • Data Transfer

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Three components

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Notifications Glances

10:09MOVE

Activity

EXERCISESTAND

Watch Apps

AM PM

Cancel Set

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0 00:

https://developer.apple.com/watch/human-interface-guidelines/app-components/

5Not possible to mix

hierarchicalpage-basedWatchKitNo native watch apps Limited UI possibilities - No drawing, static only - Only standard elements like labels,

images - Either page-based navigation or

hierarchical

https://developer.apple.com/watch/human-interface-guidelines/app-components/

Designing a Watch App for the XebiCon Schedule app

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XebiCon app for iPhone

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Design for Apple Watch

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Don’t do a design like this

Why did we ditch it?The Watch is slow - opening a view is slow. So a deep navigation doesn’t work.

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Who would read this on such a small screen?

There are many things that just don’t work on a very small screen The user always has his phone with him

Another approach

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Design for WatchKeep things simple and fast Don’t port your entire app to the watch - Structure can be different Focus on one important aspect of your app - What does the user want to do in a very short amount of time?

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Architecture

12https://developer.apple.com/library/prerelease/ios/documentation/General/Conceptual/WatchKitProgrammingGuide/

User Actions

13https://developer.apple.com/library/prerelease/ios/documentation/General/Conceptual/WatchKitProgrammingGuide/

App

WatchKit Extension

Initial Data

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App

WatchKit Extension

Data

We can’t execute code in the Watch. We can do an HTTP Request from the Extension, but… - Apple says no - Will stop complete when

Watch app is closed Right place is our app - And in our case the app likely

already has the data so no need for request

App

WatchKit Extension

Sharing dataEnter technical note TN2408 - File coordinators and shared containers is a no-no Instead use - CFPreferences - `writeToFile:atomically:` (Atomic write) - SQLite - Core Data

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Oh and let's not forgetIn no way is your data guaranteed to be stored with SQLite and Core Data.

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Think about writing data thoughSQLite and Core Data double entries

- Atomic writes, last writer wins

Storing in the cloud works very well - Be it CloudKit or a random web address

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What aboutopenParentApplication:reply: application:handleWatchKitExtensionRequest:reply:

It is - Pretty slow - Gets even slower with more data - But potentially very useful, it wakes up the containing app

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MMWormhole

As simple as[self.wormhole passMessageObject: @{@"buttonNumber" : @(1)} identifier:@"button"]; [self.wormhole listenForMessageWithIdentifier:@"button" listener:^(id messageObject) { self.numberLabel.text = [messageObject[@“buttonNumber"] stringValue]; } ];

Internally uses Darwin Notifications and atomic writes

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[self.wormhole passMessageObject: @{@"buttonNumber" : @(1)} identifier:@"button"];[self.wormhole listenForMessageWithIdentifier:@"button" listener:^(id messageObject) { self.numberLabel.text = [messageObject[@"buttonNumber"] stringValue]; } ];

Too much complexity?In the end, we made due with a shared NSUserDefaults

- Have the iPhone figure out when and how to fetch data - Silent push notifications - Preparing and staging data

Apple Watch screen is tiny - So how much data do you really need? - Focus on “the interaction”

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ConclusionThe Apple Watch is still early stages - Native coming soon - Hopefully more stability and better API’s coming

along with it

Complement your iPhone app with a Watch App really designed for the watch - Simplicity & Speed - Pay attention to integration with the iPhone

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Questions?

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Find us on Twitter

@lwesterhoff

@leenarts