我使用ImagePickerController来获取个人资料图片。用户有一个按钮。该按钮触发CamRoll功能。单击该按钮时，将ImagePickerViewController显示法线，但didFinishPickingMediaWithInfo不会调用。在早期版本的Swift
/ Xcode中，调用了相同的代码。这是我的代码。

import UIKit

class AnnonseViewController: UIViewController, UIImagePickerControllerDelegate {

@IBOutlet var Image: UIImageView!

override func viewDidLoad() {
    super.viewDidLoad()

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.

}

@IBAction func CamRoll(_ sender: Any) {

    let imagePicker = UIImagePickerController()

    imagePicker.delegate = self

    imagePicker.sourceType = UIImagePickerControllerSourceType.photoLibrary

    self.present(imagePicker, animated: true, completion: nil)

}

private func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [AnyHashable: Any]) {
    var image = info[UIImagePickerControllerOriginalImage] as! UIImage

    let imageSize = image.size
    let width = imageSize.width
    let height = imageSize.height

    if width != height {
        let newDimensions = min(width,height)
        let widthOffset = (width - newDimensions) / 2
        let heightOffset = (height - newDimensions) / 2

        UIGraphicsBeginImageContextWithOptions(CGSize(width: newDimensions, height: newDimensions), false, 0.0)

        image.draw(at: CGPoint(x: -widthOffset, y: -heightOffset), blendMode: .copy, alpha: 1.0)

        image = UIGraphicsGetImageFromCurrentImageContext()! as UIImage
        UIGraphicsEndImageContext()

    }

    UIGraphicsBeginImageContext(CGSize(width: 150, height: 150))

    _ = UIGraphicsGetCurrentContext()

    image.draw(in: CGRect(x: 0, y: 0, width: 150, height: 150))

    let smallImage = UIGraphicsGetImageFromCurrentImageContext()

    Image.image = smallImage

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


}

func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
    picker.dismiss(animated: true, completion: nil)
}

}

为什么不调用该代码？