UnsafeMutablePointer<Void> to [NSObject : AnyObject]

Question

我正在重写NSResponder的mouseEntered(theEvent: NSEvent)方法，并希望检索在Swift中创建NSTrackingArea时设置的值。我使用这构造函数创建NSTrackingArea，并将以下对象作为userInfo传递。

let trackerData = ["myTrackerKey": view]
let trackingArea = NSTrackingArea(rect: trackingRect, options: [.EnabledDuringMouseDrag, .MouseEnteredAndExited, .ActiveInActiveApp], owner: self, userInfo: trackerData)

(view : NSView和trackingRect : NSRect都存在)

我将trackerData设置为userInfo，以便稍后在mouseEntered(theEvent: NSEvent)中阅读。

override func mouseEntered(theEvent: NSEvent) {
    // This does not work
    let data1 = theEvent.userData as [NSObject : AnyObject]
    let data2 = theEvent.userData as [String : NSView]
    let data3 = theEvent.userData as NSDictionary
}

我的代码是基于苹果提供的这个目标-C样本代码。引用SuggestionsWindowController.m的第372行

HighlightingView *view = [(NSDictionary*)[event userData] objectForKey: kTrackerKey];

那么我如何阅读事件的userData呢？

我看过这个StackOverflow问答，但它不起作用。

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Answer 1

如果要从事件中读取trackerData，则必须从跟踪区域获取用户信息。

if let userInfo = theEvent.trackingArea?.userInfo {
  let trackerData = userInfo["myTrackerKey"]! as! NSView
  // do something with the view
}