iOS Swift 4:从didFinishPickingMediaWithInfo获取图像格式(JPG,PNG,GIF)

Question

我正在构建一个应用程序,允许您将图像从库中上传到服务器.该服务器本质上用作图像存储库.因此,绝对有必要将其存储为原始图像格式:JPG,PNG或GIF.IE如果PNG图像具有透明度,则要保留该图像,则不能简单地将其转换为JPG.

我使用UIImagePickerControllerReferenceURL来获取图像格式:

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        let selectedImage = info[UIImagePickerControllerEditedImage] as! UIImage
        let assetPath = info[UIImagePickerControllerReferenceURL] as! NSURL

        if (assetPath.absoluteString?.hasSuffix("JPG"))! {
            print("JPG")
        }
        else if (assetPath.absoluteString?.hasSuffix("PNG"))! {
            print("PNG")
        }
        else if (assetPath.absoluteString?.hasSuffix("GIF"))! {
            print("GIF")
        }
        else {
            print("Unknown")
        }

        self.dismiss(animated: true, completion: nil)

        self.showImageFieldModal(selectedImage: selectedImage)
    }

但UIImagePickerControllerReferenceURL已在iOS11中弃用.它建议使用UIImagePickerControllerPHAsset,但这不是URL.我不确定我应该用它作为PHAsset对象...

Answer 1

在iOS11中,您可以使用原始图像url键UIImagePickerControllerImageURL并使用URL resourceValues方法获取它typeIdentifierKey:

if #available(iOS 11.0, *) {
    if let imageURL = info[UIImagePickerControllerImageURL] as? URL {
        print(imageURL.typeIdentifier ?? "unknown UTI")  // this will print public.jpeg or another file UTI
    }
} else {
        // Fallback on earlier versions
}

您可以使用typeIdentifier此答案中的扩展名来查找fileURL类型标识符:

extension URL {
    var typeIdentifier: String? {
        return (try? resourceValues(forKeys: [.typeIdentifierKey]))?.typeIdentifier
    }
}