如何从UIImagePickerController获取经过授权的PHAsset？

Question

我有这段代码:

@IBAction func importButtonPressed(_ sender: Any) {
        self.imagePicker.sourceType = .photoLibrary
        self.imagePicker.allowsEditing = true
        self.imagePicker.mediaTypes = [kUTTypeMovie as String, kUTTypeImage as String]

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

这里展示了UIImagePicker完美的效果。当我想要使用选中的项目获取PHAsset的日期时：

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        guard info[UIImagePickerControllerMediaType] != nil else { return }
        let mediaType = info[UIImagePickerControllerMediaType] as! CFString
        switch mediaType {
        case kUTTypeImage:
            if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
                ...
            }
            break
        case kUTTypeMovie:
            if let videoURL = info[UIImagePickerControllerMediaURL] as? URL, let pickedAsset = info[UIImagePickerControllerPHAsset] as? PHAsset {
                print("kUTTypeMovie")
                MyVariables.isScreenshot = false
                let creationDate = pickedAsset.creationDate
                print(creationDate,"creationDate")
            }
            break
        case kUTTypeLivePhoto:
            print("livePhoto")
            dismiss(animated: true, completion: nil)

            break
        default:
            dismiss(animated: true, completion: nil)

            print("something else")
            break
        }
    }

现在，当我选择一个视频时，例如print（“kUTTypeMovie”）失败，我认为这是因为let pickedAsset = info [UIImagePickerControllerPHAsset] as？PHAsset 失败。

在其他地方（参见UIImagePickerControllerDelegate从选定的图像中获取日期在iOS 11中），我看到也许是因为我需要授权才能选择PHAssets。

所以我将我的第一段代码更改为：

@IBAction func importButtonPressed(_ sender: Any) {

        let status = PHPhotoLibrary.authorizationStatus()

        switch status {
        case .authorized:
            PHPhotoLibrary.requestAuthorization({status in
                if status == .authorized {
                    self.imagePicker.sourceType = .photoLibrary
                    self.imagePicker.allowsEditing = true
                    self.imagePicker.mediaTypes = [kUTTypeMovie as String, kUTTypeImage as String]

                    self.present(self.imagePicker,animated: true, completion: nil)
                }
            })
        case .denied:
            print("denied")
        // probably alert the user that they need to grant photo access
        case .notDetermined:
            print("not determined")
        case .restricted:
            print("restricted")
            // probably alert the user that photo access is restricted
        }

    }

然而现在当我按下导入按钮时，它会崩溃并显示lldb错误:

libsystem_kernel.dylib`__abort_with_payload:
    0x1854f7040 <+0>:  mov    x16, #0x209
    0x1854f7044 <+4>:  svc    #0x80
->  0x1854f7048 <+8>:  b.lo   0x1854f7060               ; <+32>
    0x1854f704c <+12>: stp    x29, x30, [sp, #-0x10]!
    0x1854f7050 <+16>: mov    x29, sp
    0x1854f7054 <+20>: bl     0x1854d8bdc               ; cerror_nocancel
    0x1854f7058 <+24>: mov    sp, x29
    0x1854f705c <+28>: ldp    x29, x30, [sp], #0x10
    0x1854f7060 <+32>: ret    

所以显然我没有做对。我应该怎么做呢？

- BigBoy1337

Answer 1

以下崩溃是由于缺少访问照片库的权限引起的，

此应用程序已崩溃，因为它尝试访问隐私敏感数据而没有使用说明。应用程序的Info.plist必须包含一个NSPhotoLibraryUsageDescription键，其中包含一个字符串值，向用户解释应用程序如何使用这些数据。

在您的Info.plist中添加NSPhotoLibraryUsageDescription键，并添加以下描述，它将正常工作。

编辑 您还应按以下方式正确使用PhotoLibrary授权。

@IBAction func importButtonPressed(_ sender: Any) {

    PHPhotoLibrary.requestAuthorization({status in
        switch status {
        case .authorized:
            self.imagePicker.sourceType = .photoLibrary
            self.imagePicker.allowsEditing = true
            self.imagePicker.mediaTypes = [kUTTypeMovie as String, kUTTypeImage as String]

            self.present(self.imagePicker,animated: true, completion: nil)
        case .denied:
            print("denied")
        // probably alert the user that they need to grant photo access
        case .notDetermined:
            print("not determined")
        case .restricted:
            print("restricted")
            // probably alert the user that photo access is restricted
        }
    })
}

- Kamran