getting started with developing for the apple watch

Getting Started with Developing for the Apple Watch

Murtza Manzur, Developer Evangelist at InMobi

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Agenda

● Apple Watch architecture● Hello World app for the Apple Watch ● Counter app for the Apple Watch● Communicating from the Apple Watch to the iOS App

Architecture

● Apple Watch app requires an iOS app● WatchKit apps have two parts○ A WatchKit extension that runs on iPhone ○ A set of user interface resources that are installed on

Apple Watch. ● Glance○ Supplemental way for the user to view important

information from your app

Architecture

● When Apple Watch app is launched, WatchKit extension on iPhone runs in the background ○ Updates UI and responds to user interactions

● Watch App○ Storyboard and resource files

● WatchKit Extension○ Code associated with the Watch App is executed here

Architecture

Hello World App for the Apple Watch

● Let’s build a Hello Word app

Hello World App - Step 1

Click Create a new Xcode Project.

Hello World App - Step 2

Select Single View Application, and then click Next.

Hello World App - Step 3

Enter values for Product Name and Organization Name. Select Objective-C as Language and iPhone as Devices. Leave Use Core Data unchecked.

Hello World App - Step 4

Select a directory to save the project in, and then click Create.

Hello World App - Step 5

Select File, New, then click on Target.

Hello World App - Step 6

Select Apple Watch in the left-hand menu. Then click Next.

Hello World App - Step 7

Uncheck Notification Scene and Glance Scene. Then click Finish.

Hello World App - Step 8

Click Activate.

Hello World App - Step 9

In the left-hand menu, select the Interface.storyboard file from the WatchKit App folder.

Hello World App - Step 10

This is the Interface Builder for Apple Watch. In the next step, we will drag a Label object from the Object Library to the Apple Watch interface.

Interface Controller

● Like a View Controller in iOS● Support two navigation styles, which are mutually exclusive○ Hierarchal○ Paged based

● Interface navigation through segues or programmatically○ To implement a modal in your storyboard file, create a

modal segue.○ To implement a modal programmatically, call the

presentControllerWithName:context: method

Interface Controller

● awakeWithContext○ System calls this method at initialization time to provide

the interface controller with any relevant contextual data from a previous interface controller

● willActivate○ System calls this method to notify the interface controller

that its content is about to be displayed onscreen● didDeactivate○ System calls this method to notify the interface controller

that it is no longer onscreen

Hello World App - Step 10

Search for the Label object in the Object Library (lower right-hand menu in Xcode). Then drag the Label Object to the Apple Watch interface.

Interface Objects

● Arrange themselves● Two unique view objects to

Watch App○ Date○ Timer

● Can be embedded in vertical or horizontal groups

Hello World App - Step 11

Double click on the Label object you added to the Apple Watch interface, and change the text to Hello World.

Hello World App - Step 11

Click the run icon in Xcode. This will build your app, and then run it in a simulator.

Hello World App - Step 12

To enable the Apple Watch simulator, select Hardware, External Displays and then click on Apple Watch - 42mm.

Hello World App - Step 13

Simulator will show Hello World.

Counter App for the Apple Watch

● Let’s build a counter app for the Apple Watch

Counter App - Step 1

Navigate back to Interface.storyboard. Double click the label text to change it from Hello World to 0. Add two Button objects from the Object Library. Rename the button text: one for “+”, and a second for “-”.

Counter App - Step 2

Navigate to the InterfaceController.m file in the WatchKit Extension folder. As shown in the screenshot above, add two properties between @interface and @end.

Counter App - Step 3

In @implementation, add two methods to increment and decrement the counter property. We will connect these two methods with the button objects in the Interface Builder.

Counter App - Step 4

In @implementation, add a third method to set the text of the counter label in the interface to value of the counter property. We will connect the counter label property to the counter label object in the interface in a later step.

Counter App - Step 5

Connect the decrementCounter action to the “-” button object. Connect the incrementCounter action to the “+” button object.

Counter App - Step 6

Connect the counterLabel property from the Interface Controller to the counter label object in the interface.

Counter App - Step 7

Click the run icon in Xcode.

Counter App - Step 8

The Watch App will run in the simulator. If the “+” and “-” buttons are working correctly, they will increment and decrement the counter.

Communicating from Watch to iOS App

● Use openParentApplication method to send data from WatchKit extension to iOS app■ Passed as a dictionary object

● handleWatchKitExtensionRequest method to receive data on iOS app

● Reference○ https://developer.apple.

com/library/prerelease/ios/documentation/WatchKit/Reference/WKInterfaceController_class/index.html

Resources

● WatchKit Development Tips○ https://developer.apple.com/watchkit/tips/

● Developing for Apple Watch○ https://developer.apple.

com/library/ios/documentation/General/Conceptual/WatchKitProgrammingGuide/index.html

Resources

● Tips for Submitting Apple Watch App○ http://www.fiveminutewatchkit.com/blog/2015/4/2/submitting-

your-watchkit-app● Bezel, a tool to simulate the look of an Apple Watch

Murtza ManzurDeveloper Evangelistmurtza.manzur@inmobi.com

Questions?