There are several methods available to us to facilitate the transfer of data in both directions between the iPhone and its paired Apple Watch using methods supplied by Apple's WatchConnectivity framework. In this chapter, we will use some of its Application Context methods, which are possibly the simplest to implement, as well as being best suited to our requirements. We will sketch out these requirements first.

Using ApplicationContext methods from the WatchConnectivity class involves populating and sending a Dictionary object, the same type of object that you will probably have used in iOS apps already. These Dictionary objects must be in the form [String :AnyObject], which is specified by the ApplicationContext methods we will be using. Since both the watch app and the phone app will need to be using exactly the same keys (so in this case, the String) to access the values of the Dictionary, it is advisable to create a file of predefined constant String objects, which will save us the trouble caused by typing mistakes, meaning that one app sends, for example, ["Color" : RedObject], while the other looks for ["color" : RedObject] (note the capitalization), an easy mistake to make, and one that will cause your code to fail.

To do this, we must create a file that is accessible to both apps, which means ensuring it is available to both the C-Quence and the C-QuenceWatchKit Extension targets:

let kPlayerName = "playerName"

We want to make the first call to PhoneConnectivityManager.sharedManager (which is the call that will actually instantiate the shared instance of that class) early in the app's lifecycle, and the earliest place we can do that is when the AppDelegate class (created for us by Xcode's template) is itself instantiated. Add the following line of code to the AppDelegate class in the AppDelegate.swift file:

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    let connectivityManager = PhoneConnectivityManager.sharedManager

...

Select ViewController.swift in the project navigator and add the following IBOutlet to the ViewController class:

    @IBOutlet weak var playerNameTextFile: UITextField!

Then add the following methods to the class:

    @IBAction func saveNameButtonTapped(sender: AnyObject) {
        savePlayerName()//1
    }

    func savePlayerName() {
        if playerNameTextField.text != "" { //2
PhoneConnectivityManager.sharedManager.sendNameToWatch(playerNameTextField.text!) //3
        }
        “playerNameTextField.resignFirstResponder ()//4
    }

In the Main.storyboard file, drag a Button object onto the interface, placing it in the center of the view using Interface Builder's layout guidelines.

Change its Title from Button to something more informative, such as Send Name To Watch.

We must now add Layout Constraints to the button, so that it will position itself correctly whatever the orientation and size of the view in which it appears. We can do this directly in Interface Builder:

Control-drag from the button onto the containing view at an angle of roughly 45 degrees, and release the mouse. You will be presented with the following contextual menu:

Follow these steps:

Using the same control-drag methods as earlier in Chapter 3, C-Quence – A Memory Game connect the TextField object in the Document Outline to the @IBOutlet weak varplayerNameTextField: UITextField!in the ViewControllerclass.

Connect the Button object to the savePlayerName method of the ViewController class.

On the watch side of things, it is even more important to create the shared instance of the WatchConnectivityManager class early in the app's lifecycle, since there may be messages waiting that were sent while the app was not running, so add the following code to the ExtensionDelegate class that was created by the Xcode template:

class ExtensionDelegate: NSObject, WKExtensionDelegate {
    
    let watchConnectivityManager = WatchConnectivityManager.sharedManager

...

We are very close to being finished!

All we need to do now is add a method that retrieves the stored player name from NSUserDefaults. When the resultLabel method of the InterfaceController displays the player's score, it must first call this new method to find out what text to display.

Add the following method to the InterfaceController class:

    func textForResult(result: Int) -> String {
        if let playerName = NSUserDefaults.standardUserDefaults().objectForKey(kPlayerName) as! String? {
           return "Hey (playerName), you scored (result)"
        } else {
           return "Not bad! You scored (result)"
        }
    }

Once again, we use kPlayerName as a reliable way to check whether the NSUserDefaults contains a String with that key. We don't really need to check here if it is a String, because if it exists, it can't be anything else, but this check costs nothing, and may prevent trouble later on due to programmer mistakes.

Finally, we change the endGame method to call textForResult before setting the text of the resultLabel:

    func endGame(result: Int){
        gameboardGroup.setHidden(true)
        resultLabel.setHidden(false)

        let resultText = textForResult(result)
        resultLabel.setText(resultText)

        playButton.setHidden(false)
        playButton.setTitle("Play Again")
        gameLogic.clearGame()
    }