PHCachingImageManager.default().requestAVAsset(forVideo: asset,options: nil,resultHandler:
    { (givenAsset,audioMix,info) in

        let videoAsset = givenAsset as! AVURLAsset
        let videoURL = videoAsset.url

        DispatchQueue.main.async {
            let activityViewController = UIActivityViewController(
                activityItems: [videoURL],applicationActivities: nil)
            activityViewController.excludedActivityTypes = [UIActivityType.saveToCameraRoll]

            if let popoverPresentationController = activityViewController.popoverPresentationController {
                popoverPresentationController.barButtonItem = (sender)
            }

            self.present(activityViewController,animated: true,completion: nil)
        }
})

这似乎适当地提出了UIActivityController并且只适用于某些活动：

>消息 – ✔️Works,正确导出视频.
> AirDrop – ✖️Shows“失败”
> DropBox – ✖️提供正确的DropBox View,但说“发生了未知错误”