Adding observer for KVO without pointers using Swift

Question

In Objective-C, I would normally use something like this:

static NSString *kViewTransformChanged = @\"view transform changed\";
// or
static const void *kVie         


        

Answer 1

Now that KVOContext is gone in Xcode 6 beta 3, you can do the following. Define a global (i.e. not a class property) like so:

let myContext = UnsafePointer<()>()

Add an observer:

observee.addObserver(observer, forKeyPath: …, options: nil, context: myContext)

In the observer:

override func observeValueForKeyPath(keyPath: String!, ofObject object: AnyObject!, change: [NSObject : AnyObject]!, context: UnsafePointer<()>) {
    if context == myContext {
        …
    } else {
        super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context)
    }
}