如何在Swift中从CFTypeRef转换为AXUIElement

此代码生成预期的调试输出类型= AXUIElement,但转储堆栈并表示动态转换在转换的实际点失败：

func mainWindow() {
    var ptr: Unmanaged<AnyObject>?
    let kAXMainWindow: CFString! = "AXMainWindow" as NSString
    let appRef: AXUIElement! = AXUIElementCreateApplication(self.pid()).takeRetainedValue()

    let err = AXUIElementCopyAttributeValue(appRef, kAXMainWindow, &ptr)
    if err == AXError(kAXErrorSuccess) {
        let val: AnyObject? = ptr?.takeRetainedValue()
        if val != nil {
            let value: AnyObject = val!
            let description = CFCopyTypeIDDescription(CFGetTypeID(value))
            println("type = \(description)")
            let element = value as AXUIElement
        }
        else {
            println("got nil result")
        }
    }
}

完成这项工作的正确方法是什么？

此代码适用于XCode 6.1和Swift 1.1.

然而,现在是3年后,Swift已经变得更好了.当您搜索如何使用Swift的Accessibility API时,这仍然是最佳结果.所以我回来用我目前最简单的方式更新：

func AXUIWindowArray(processIdentifier pid:pid_t) -> [AXUIElement] {
    var result = [AXUIElement]()
    var windowList: AnyObject? = nil // [AXUIElement]

    let appRef = AXUIElementCreateApplication(pid)
    if AXUIElementCopyAttributeValue(appRef, "AXWindows" as CFString, &windowList) == .success {
        result = windowList as! [AXUIElement]
    }
    return result
}