使用didFinishPickingMediaWithInfo方法时，无法使用类型为“”(Int，@escaping () -> ())“”的参数列表调用“”UIImage“”

Question

我之前使用过下面的UIImage Extension：

extension UIImage
{
    func scaleImage(_ maxDimension: CGFloat) -> UIImage?
    {
        var scaledSize = CGSize(width: maxDimension, height: maxDimension)

        if size.width > size.height
        {
            let scaleFactor = size.height / size.width
            scaledSize.height = scaledSize.width * scaleFactor
        }
        else
        {
            let scaleFactor = size.width / size.height
            scaledSize.width = scaledSize.height * scaleFactor
        }

        UIGraphicsBeginImageContext(scaledSize)
        draw(in: CGRect(origin: .zero, size: scaledSize))

        let scaledImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return scaledImage
    }
}

我在我的ViewController中使用了这个扩展，如下所示：

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any])
{
    if let selectedImage = info[UIImagePickerControllerOriginalImage] as? UIImage
    {
        let scaledPhoto = selectedImage.scaleImage(640)
        {
            activityIndicatorOutlet.startAnimating()
            dismiss(animated: true, completion:
                {
                    //recognize the image
            })
        }

    }
}

但是Xcode给出了一个错误。因为didFinishPickingMediaWithInfo方法发生了如下变化：

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {

}

因此，我用最新版本更改了didFinishPickingMediaWithInfo方法：

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {

}

然后Xcode希望我改变这一点：

'UIImagePickerControllerOriginalImage' has been renamed to 'UIImagePickerController.InfoKey.originalImage'
Replace 'UIImagePickerControllerOriginalImage' with 'UIImagePickerController.InfoKey.originalImage'

我已经按照Xcode的要求修改了上面的代码：

if let selectedImage = info[UIImagePickerController.InfoKey.originalImage] as? UIImage
        {
            let scaledPhoto = selectedImage.scaleImage(640)
            {
                activityIndicatorOutlet.startAnimating()
                dismiss(animated: true, completion:
                    {
                        //recognize the image
                })
            }

        }

最后，Xcode在以下代码行中显示了一个错误：

let scaledPhoto = selectedImage.scaleImage(640)

下面是错误：

Cannot invoke 'scaleImage' with an argument list of type '(Int, @escaping () -> ())'

我该如何解决这个问题呢？

Answer 1

从scaleImage函数获取图像时，遗漏了let关键字

像下面这样修改你的代码，让它工作起来

if let selectedImage = info[UIImagePickerController.InfoKey.originalImage] as? UIImage {

     if let scaledPhoto = selectedImage.scaleImage(100) {

         print(scaledPhoto)
         activityIndicatorOutlet.startAnimating()
         dismiss(animated: true, completion: {
                //recognize the image
         })
     }
}