检测airplay设备是否可用

Question

我只想在有airplay设备（用户的iPhone除外）时在iPhone应用程序中将Airplay图标显示为UIBarButtonItem。

var volumeView = MPVolumeView!

我已经在UIBarButtonItem中设置了viewDidLoad()：

volumeView = MPVolumeView(frame: CGRect(x: 0.0, y: 0.0, width: 0.0, height: 0.0))
volumeView.showsVolumeSlider = false
let airplayBarButtonItem = UIBarButtonItem(customView: volumeView)
if let routeButton = volumeView.subviews.last as? UIButton,
  let routeButtonTemplateImage = routeButton.currentImage?.withRenderingMode(.alwaysTemplate) {
  volumeView.setRouteButtonImage(routeButtonTemplateImage, for: .normal)
  volumeView.tintColor = myColor
}

volumeView.showsRouteButton = volumeView.areWirelessRoutesAvailable

在viewWillAppear()中：

volumeView.showsRouteButton = volumeView.areWirelessRoutesAvailable

现在，当Airplay设备可用时，应用程序需要更新当前屏幕，有办法吗？

编辑：此通知似乎已弃用，是否有替代品？ https://developer.apple.com/documentation/mediaplayer/mpvolumeviewwirelessrouteactivedidchangenotification?language=objc#discussion