How to reference non-supported frameworks in Watch OS 2

Question

I updated my app to the latest swift 2.0 syntax. In doing so, My watchkit app has become broken. The issue is the watchkit app references a class that references the framework AVFoundation. WatchOS2 apparently now no longer supports some of the standard frameworks:

Support for network-based operations includes the following technologies:

WatchKit extensions can access the network directly through an NSURLSession object. WatchKit extensions have full access to the NSURLSession capabilities, including the ability to download files in the background. For information on how to use this class, see URL Loading System Programming Guide. The Watch Connectivity framework supports bidirectional communication between your Watch app and iOS app. Use this framework to coordinate activities between the two apps. See Communicating with Your Companion iOS App.

Available System Technologies for WatchKit

So now I cannot compile the watch kit code as "no such module found" is an error message when trying to use the AVFoundation framework. How can I get around this and keep referencing that class and framework in my apple watch app. Should I be communicating data between the phone and the watch? Is there a way to link the framework to the extension?

What I am trying to do is the following, in my InterfaceController:

 override func willActivate() {
    super.willActivate()

    let defaultsShared = NSUserDefaults(suiteName: "somesharedappgroup")
    let defaults = NSUserDefaults.standardUserDefaults()


     if let barcodeString = defaultsShared!.objectForKey("barcode") as? String {
        if let barcodeContent = RSUnifiedCodeGenerator.shared.generateCode(barcodeString, machineReadableCodeObjectType: AVMetadataObjectTypeCode39Code) {
            barcode.setImage(barcodeContent)
            label.setText("ID: \(barcodeString)")
        } else {
            label.setText("Please setup extensions in the settings of SHPID.")
            barcode.setImage(nil)
        }
    } else {

        label.setText("Please setup extensions in the settings of SHPID.")
        barcode.setImage(nil)

    }
}

The RSUnifiedCodeGenerator being a class that utilizes AVFoundation to generate barcode images from strings. Furthermore, the type that generator takes is an AVObject: AVMetadataObjectTypeCode39Code. This solution worked well in the first WatchOS, but now remains broken in OS 2. I see that WatchConnectivity may be a solution, and have it just pass me the barcode from the phone itself, but that would require I stop supporting iOS 8. What is the best solution, if any, for using AVFoundation with WatchOS 2. If I can not do that, how else should I go about passing this image to the watch from the phone when called. Thanks.

Answer 1

This is an example on how you could use WatchConnectivity for your app.

Please not that this example is rough and does not handle error. The session management should also get some attention for a stable product.

iPhone AppDelegate

import UIKit
import WatchConnectivity
import AVFoundation
import RSBarcodes

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, WCSessionDelegate {

  var window: UIWindow?


  func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    // Override point for customization after application launch.

    if WCSession.isSupported() {
      let session = WCSession.defaultSession()
      session.delegate = self
      session.activateSession()
    }

    return true
  }

  // On Watch sends the message.
  // Will not reply as we will push a data message with image.
  func session(session: WCSession, didReceiveMessage message: [String : AnyObject]) {
    if "generateBarcode" == message["id"] as! String {
      let code = message["code"] as! String
      let barcodeImage = RSUnifiedCodeGenerator.shared.generateCode(code,
        machineReadableCodeObjectType: AVMetadataObjectTypeCode39Code)!

      if WCSession.isSupported() {
        let session = WCSession.defaultSession()
        session.delegate = self
        session.activateSession()

        session.sendMessageData(UIImagePNGRepresentation(barcodeImage)!,
          replyHandler: nil, errorHandler: nil)
      }
    }
  }
}

Watch InterfaceController

import WatchKit
import Foundation
import WatchConnectivity

class InterfaceController: WKInterfaceController, WCSessionDelegate {

  @IBOutlet var barcodeImage: WKInterfaceImage!

  override func willActivate() {
    super.willActivate()

    if WCSession.isSupported() {
      let session = WCSession.defaultSession()
      session.delegate = self
      session.activateSession()

      // Send a message requesting a barcode image
      session.sendMessage(
        ["id": "generateBarcode", "code": "2166529V"],
        replyHandler: nil, // Do not handle response, iPhone will push a data message
        errorHandler: nil)
    }
  }

  // On iPhone pushes a data message
  func session(session: WCSession, didReceiveMessageData messageData: NSData) {
    barcodeImage.setImage(UIImage(data: messageData))
  }
}