PHPickerViewController的“取消按钮”不能在iOS 15中工作

Question

我使用PHPickerViewController来选择iOS 15中的用户配置文件图片，我使用的是UIKit框架。我有以下代码：

var pickerConfig = PHPickerConfiguration(photoLibrary: .shared())
pickerConfig.selectionLimit = 1
pickerConfig.filter = .images
let pickerView = PHPickerViewController(configuration: pickerConfig)
pickerView.delegate = self
self.present(pickerView, animated: true)

选择器在选择图像和委派结果时工作正常。但是，当按下Cancel按钮时，什么都不会发生，选择器也不会像预期的那样被取消。

当按下PHPickerViewController实例自己的Cancel按钮时，如何关闭它？

编辑：

PHPickerViewControllerDelegate方法的实现如下：

func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult])
    {
        results.first?.itemProvider.loadObject(ofClass: UIImage.self) { [unowned self] reading , error in
            guard let image = reading as? UIImage, error == nil else
            {
                DispatchQueue.main.async {
                    picker.dismiss(animated: true)
                    self.profilePictureHasError = true
                    self.toggleDoneButtonEnabled()
                }
                return
            }
            self.profilePictureHasError = false
            DispatchQueue.main.async {
                picker.dismiss(animated: true)
                self.profilePictureHasChanged = self.userProfilePicture != image
                if self.profilePictureHasChanged
                {
                    self.profilePictureView.image = image
                    self.toggleDoneButtonEnabled()
                }
            }
        }
    }

Answer 1

您需要在picker(_:didFinishPicking:)委托方法中自己排除选择器，当用户在单击cancel按钮时完成选择、或时调用该方法。

来自苹果文档 for picker(_:didFinishPicking:)

The system doesn’t automatically dismiss the picker after calling this method.

例如：

func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
    // Do something with the results here
    picker.dismiss(animated: true)
}

当前委托代码只在结果数组非空时(即当用户选择了图像时)才调用picker.dismiss。当单击“取消”按钮时，将使用空结果数组调用委托方法。

通过将以下内容添加到委托方法中的代码顶部，可以解决此问题：

if results.isEmpty {
    picker.dismiss(animated: true)
    return
}

Answer 2

您只需在objc功能中将其包装出来，以使“取消”按钮工作。

    @objc
    func didOpenPhotos() {
        lazy var pickerConfig = PHPickerConfiguration()
        pickerConfig.filter = .images
        pickerConfig.selectionLimit = 1
        let pickerView = PHPickerViewController(configuration: pickerConfig)
        pickerView.delegate = self
        self.present(pickerView, animated: true)
    }

在任何地方叫它