函数调用参数类型与URL类型不匹配

I have recently started programming in Swift 4 and have a compile error to resolve. I have an @IBACTION function called playVideo which plays a video but I want to be able to capture frames from the video as well for further processing. This @IBAction function is shown below:

我最近开始在Swift 4中编程并且有一个编译错误要解决。我有一个名为playVideo的@IBACTION函数播放视频,但我希望能够从视频中捕获帧以及进一步处理。这个@IBAction函数如下所示:

@IBAction func playVideo (_ sender: AnyObject) {
    self.present(self.playerController, animated:true, completion: {
        self.playerController.player?.play()
        var grabTime = 1.22  
        generateThumbnail(url: URL, fromTime: Float64(grabTime))
    })
}

The function playVideo which calls (generateThumbnail) is provided below. When I attempt to compile the program it fails with the function call "generateThumbnail(url:URL, fromTime: Float64(grabTime))" in playVideo with the error:

调用(generateThumbnail)的函数playVideo如下所示。当我尝试编译程序时,它在playVideo中使用函数调用“generateThumbnail(url:URL,fromTime:Float64(grabTime))”失败,错误如下:

"cannot convert value of type 'URL.Type' to expected argument type 'URL'

“无法将'URL.Type'类型的值转换为预期的参数类型'URL'

Can anyone help to resolve this issue? I have looked on this site for other errors of this type but they don't seem to cover these particular circumstances which is why I raised this now.

任何人都可以帮忙解决这个问题吗?我在这个网站上看过这种类型的其他错误,但它们似乎并没有涵盖这些特殊情况,这就是我现在提出这个问题的原因。

func generateThumbnail(url: URL, fromTime:Float64) -> UIImage? {
    let asset :AVAsset = AVAsset(url: url)
    let assetImgGenerate : AVAssetImageGenerator = AVAssetImageGenerator(asset: asset)
    assetImgGenerate.appliesPreferredTrackTransform = true
    assetImgGenerate.requestedTimeToleranceAfter = kCMTimeZero;
    assetImgGenerate.requestedTimeToleranceBefore = kCMTimeZero;
    let time        : CMTime = CMTimeMakeWithSeconds(fromTime, 600)
    var img: CGImage?
    do {
        img = try assetImgGenerate.copyCGImage(at:time, actualTime: nil)
    } catch {
    }
    if img != nil {
        let frameImg    : UIImage = UIImage(cgImage: img!)
        return frameImg
    } else {
        return nil
    }
}

1 个解决方案

#1

Change

    generateThumbnail(url: URL, fromTime: Float64(grabTime))

To

    generateThumbnail(url: url, fromTime: Float64(grabTime))