ios - 错误 : Cannot assign a value of type 'AnyObject?' to a value of type 'NSURL'

Question

出现错误:无法分配“AnyObject?”类型的值为“NSURL”类型的值

我的代码:

var videoPlayer = MPMoviePlayerController()
    var mediaUI = UIImagePickerController()
    var videoURL = NSURL()



 func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]){

              // error in below first line

        self.videoURL = info[UIImagePickerControllerMediaURL]
      mediaUI.dismissViewControllerAnimated(true, completion: nil)
        self.videoPlayer = MPMoviePlayerController()
        self.videoPlayer.contentURL = videoURL
        self.videoPlayer.view.frame = CGRectMake(0,0,self.view.frame.size.width,460)
        self.view.addSubview(self.videoPlayer.view)
        self.videoPlayer.play()

         }

如何更改该代码以解决我的错误。

Answer 1

info[UIImagePickerControllerMediaURL] 是 AnyObject? 类型，但 self.videoURL 是 NSURL 类型。

将结果安全地转换为 NSURL:

if let vURL = info[UIImagePickerControllerMediaURL] as? NSURL {
    self.videoURL = vURL
}

这是您修复的代码:

var videoPlayer = MPMoviePlayerController()
var mediaUI = UIImagePickerController()
var videoURL = NSURL()

func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {

    if let vURL = info[UIImagePickerControllerMediaURL] as? NSURL {
        self.videoURL = vURL
    } else {
        print("oops, no url")
    }
    mediaUI.dismissViewControllerAnimated(true, completion: nil)
    self.videoPlayer = MPMoviePlayerController()
    self.videoPlayer.contentURL = videoURL
    self.videoPlayer.view.frame = CGRectMake(0,0,self.view.frame.size.width,460)
    self.view.addSubview(self.videoPlayer.view)
    self.videoPlayer.play()

}