xcode 发现扩展时遇到 Swift 4 错误 - 照片不会在 UI 上加载

Swift 4 errors encountered while discovering extensions - photo will not load on UI

提问by sixstringsteph

I am getting the following error message when I choose a photo from the photo library to populate a UIImageView in XCode 9.2:

当我从照片库中选择一张照片以填充 XCode 9.2 中的 UIImageView 时，我收到以下错误消息：

• [discovery] errors encountered while discovering extensions: Error Domain=PlugInKit Code=13 "query cancelled" UserInfo={NSLocalizedDescription=query cancelled}

• [发现] 发现扩展时遇到的错误：Error Domain=PlugInKit Code=13 "query cancelled" UserInfo={NSLocalizedDescription=query cancelled}

The simulator is able to access the photo library and I am able to view the photos to make a selection, but when I click on the 'Choose' option to select a photo, the error is thrown and after the picker is dismissed the image is not populating the UIImageView.

模拟器能够访问照片库，我可以查看照片以进行选择，但是当我单击“选择”选项来选择照片时，会抛出错误，并且在选择器被解除后，图像是不填充 UIImageView。

I have searched Stack Overflow and am able to get rid of the error message if I do this step: From Xcode menu open: Product > Scheme > Edit Scheme > On your Environment Variables set OS_ACTIVITY_MODE in the value set disable. However, this only gets rid of the error and does not fix the issue with my selected photo not populating the UIImageView. I am new to Swift and Xcode and am stuck! Please help!

我已经搜索了 Stack Overflow，如果我执行此步骤，我能够摆脱错误消息：从 Xcode 菜单打开：产品 > 方案 > 编辑方案 > 在您的环境变量中设置 OS_ACTIVITY_MODE 在值集禁用。但是，这只能消除错误，并不能解决我选择的照片未填充 UIImageView 的问题。我是 Swift 和 Xcode 的新手并且被卡住了！请帮忙！

Here is my code:

这是我的代码：

import UIKit

class HomeVC: UIViewController, UINavigationControllerDelegate, 
UIImagePickerControllerDelegate {

@IBOutlet weak var avaImg: UIImageView!
@IBOutlet weak var usernameLbl: UILabel!
@IBOutlet weak var fullnameLbl: UILabel!
@IBOutlet weak var emailLbl: UILabel!

override func viewDidLoad() {
    super.viewDidLoad()

    //get user details from user global var (from database)
    let username = (user!["username"] as? String)?.uppercased()
    let fullname = user!["fullname"] as? String
    let email = user!["email"] as? String
    let ava = user!["ava"] as? String

    //populate labels on view
    usernameLbl.text = username
    fullnameLbl.text = fullname
    emailLbl.text = email


}

@IBAction func edit_click(_ sender: AnyObject) {

    //select ava
    let picker = UIImagePickerController()
    picker.delegate = self
    picker.sourceType = UIImagePickerControllerSourceType.photoLibrary
    picker.allowsEditing = true
    self.present(picker, animated: true, completion: nil)

    //selected image
    func imagePickerController(_ picker: UIImagePickerController, 
    didFinishPickingMediaWithInfo info: [String : AnyObject]) {
        let image = info[UIImagePickerControllerEditedImage] as? 
           UIImage
        avaImg.image = image

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

    }
}

回答by vadian

Two issues:

两个问题：

• The signature of didFinishPickingMediaWithInfois wrong. In Swift 3+ it is

  func imagePickerController(_ picker: UIImagePickerController, 
                             didFinishPickingMediaWithInfo info: [String : Any])
  

• The delegate method must be on the top level of the class (not in another method)

  @IBAction func edit_click(_ sender: Any) {
  
      //select ava
      let picker = UIImagePickerController()
      picker.delegate = self
      picker.sourceType = .photoLibrary
      picker.allowsEditing = true
      self.present(picker, animated: true, completion: nil)
  }
  
  func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
  
      //selected image
      let image = info[UIImagePickerControllerEditedImage] as? UIImage
      avaImg.image = image
      self.dismiss(animated: true, completion: nil)
  }
  

• 的签名didFinishPickingMediaWithInfo是错误的。在 Swift 3+ 中，它是

  func imagePickerController(_ picker: UIImagePickerController, 
                             didFinishPickingMediaWithInfo info: [String : Any])
  

• 委托方法必须在类的顶层（而不是在另一个方法中）

  @IBAction func edit_click(_ sender: Any) {
  
      //select ava
      let picker = UIImagePickerController()
      picker.delegate = self
      picker.sourceType = .photoLibrary
      picker.allowsEditing = true
      self.present(picker, animated: true, completion: nil)
  }
  
  func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
  
      //selected image
      let image = info[UIImagePickerControllerEditedImage] as? UIImage
      avaImg.image = image
      self.dismiss(animated: true, completion: nil)
  }