Apple Watch, WatchKit Extension and main application

Question

There is main application with logic and we extend app to Apple Watch.

After adding target xCode creates 2 more applications: extension with code and watch kit appl

Answer 1

At current state of Apple Watch Extension:

• You can share information between iOS main appliation and WatchKit Extension. Use App Groups and NSUserDefaults to access the shared information objects.

• You can not execute code from your iOS app which is trigged from actions on the Apple Watch.

At least not yet.

EDIT: As of Xcode 6.2 Beta 2

It is now possible to communicate with the parent iOS app from Apple Watch.

In WatchKit Extension call the parent application via openParentAppentApplicion. One can pass a value dictionary to the parent application and the parent application can return a value dictionary.

Watchkit Extension:

// Call the parent application from Apple Watch

// values to pass
let parentValues = [
    "value1" : "Test 1",
    "value2" : "Test 2"
]

WKInterfaceController.openParentApplication(parentValues, reply: { (replyValues, error) -> Void in
    println(replyValues["retVal1"])
    println(replyVaiues["retVal2"])
})

iOS App:

// in AppDelegate.swift
func application(application: UIApplication!, handleWatchKitExtensionRequest userInfo: [NSObject : AnyObject]!, reply: (([NSObject : AnyObject]!) -> Void)!) {
    // retrieved parameters from Apple Watch
    println(userInfo["value1"])
    println(userInfo["value2"])

    // pass back values to Apple Watch
    var retValues = Dictionary()

    retValues["retVal1"] = "return Test 1"
    retValues["retVal2"] = "return Test 2"

    reply(retValues)
}