我正在尝试使用UIActivityViewController从URL共享视频.如果我尝试使用 
 Image,我没有问题. 
  
 
分享图片作品:
let imageThump = NSURL(string: "https://example.com/image.png")
        let imageData = NSData(contentsOfURL: imageThump!) 
let objectsToShare = [comment!,imageData!]
            let activityVC = UIActivityViewController(activityItems: objectsToShare,applicationActivities: nil) 
 分享视频无效.为什么?
let videoShare = NSURL(string: "https://example.com/video.mp4")
        let videoData = NSData(contentsOfURL: videoShare!) 
let objectsToShare = [comment!,videoData!]
            let activityVC = UIActivityViewController(activityItems: objectsToShare,applicationActivities: nil)
解决方法
 这就是你怎么做的…. 
  
  
 
        let urlData = NSData(contentsOfURL: NSURL(string:"https://example.com/video.mov)")!)
            if ((urlData) != nil){
                print(urlData)
                let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,.UserDomainMask,true)
                let docDirectory = paths[0]
                let filePath = "\(docDirectory)/tmpVideo.mov"
                urlData?.writetoFile(filePath,atomically: true)
                // file saved
                let videoLink = NSURL(fileURLWithPath: filePath)
                let objectsToShare = [videoLink] //comment!,imageData!,myWebsite!]
                let activityVC = UIActivityViewController(activityItems: objectsToShare,applicationActivities: nil)
                activityVC.setValue("Video",forKey: "subject")
                //New Excluded Activities Code
                if #available(iOS 9.0,*) {
                    activityVC.excludedActivityTypes = [UIActivityTypeAirDrop,UIActivityTypeAddToReadingList,UIActivityTypeAssignToContact,UIActivityTypecopyToPasteboard,UIActivityTypeMail,UIActivityTypeMessage,UIActivityTypeOpenInIBooks,UIActivityTypePostToTencentWeibo,UIActivityTypePostToVimeo,UIActivityTypePostToWeibo,UIActivityTypePrint]
                } else {
                    // Fallback on earlier versions
                    activityVC.excludedActivityTypes = [UIActivityTypeAirDrop,UIActivityTypePrint ]
                }
                self.presentViewController(activityVC,animated: true,completion: nil)
            }