Watchkit - How pass multiple values with contextForSegueWithIdentifier

Question

I currently pass a string value from one WKInterfaceController to another using contextForSegueWithIdentifier like so:

override func contextForSegueWithIdentifier(segueIdentifier: String, inTable table: WKInterfaceTable, rowIndex: Int) -> AnyObject? {

    if segueIdentifier == "segueDetails" {
        return self.string1
    }

    // Return data to be accessed in ResultsController
    return nil
}

And then on the destination WKInterfaceController I do the following:

override func awakeWithContext(context: AnyObject?) {
    super.awakeWithContext(context)

    if let val: String = context as? String {
        self.label.setText(val)
    } else {
        self.label.setText("")
    }
    // Configure interface objects here.
}

However I want to pass multiple values, using two additional properties with string values called string2 and string3.

How can I pass additional string values to the WKInterfaceController?

Answer 1

Swift has three collection types: Array, Dictionary, and Set.

Passing the context as an array of strings:

    ...
    if segueIdentifier == "segueDetails" {
        return [string1, string2, string3]
    }

func awakeWithContext(context: AnyObject?) {
    super.awakeWithContext(context)

    // Configure interface objects here.
    if let strings = context as? [String] {
        foo.setText(strings[0])
        bar.setText(strings[1])
        baz.setText(strings[2])
    }
}

Passing the context as a dictionary:

    ...
    if segueIdentifier == "segueDetails" {
        return ["foo" : string1, "bar" : string2, "baz" : string3]
    }

func awakeWithContext(context: AnyObject?) {
    super.awakeWithContext(context)

    // Configure interface objects here.
    if let strings = context as? [String: String] {
        foo.setText(strings["foo"])
        bar.setText(strings["bar"])
        baz.setText(strings["baz"])
    }
}

Personally, I prefer using a dictionary, as the array approach would be a bit more fragile if the caller ever changed the order or the number of strings.

Either way, add necessary checks to make your code robust.