如何获取iOS画外音的选定元素

Question

我有一个iOS Swift应用程序，我想检测画外音选择了哪个元素。

尝试发送UIAccessibilitySwitchControlStatusDidChangeNotification，但我没有让它工作。

NSNotificationCenter.defaultCenter().addObserver(
            self,
            selector: "handleVoiceoverSelection",
            name: UIAccessibilitySwitchControlStatusDidChangeNotification,
            object: nil)

...

func handleVoiceoverSelection(){
    println("!!!! element selected !!!!")
}

有什么办法吗？

Answer 1

也许看看UIAccessibilityFocus？

https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UIAccessibilityFocus_Protocol/index.html