ios - PHPickerViewController 的取消按钮在 iOS 15 中不起作用

Question

我正在使用 PHPickerViewController 在 iOS 15 中为用户个人资料图片选择图像。我正在使用 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托(delegate)结果方面正常工作。但是，当按下 Cancel 按钮时，没有任何反应，而且 Picker 没有按预期关闭。

如何在按下 Cancel 按钮时关闭 PHPickerViewController 实例？

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(delegate)方法中自行关闭选择器，该方法在用户完成选择或点击取消时调用按钮。

来自Apple docs对于 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)
}

您当前的委托(delegate)代码仅在结果数组为非空时(即当用户选择了图像时)调用 picker.dismiss。点击取消按钮时，将使用空结果数组调用委托(delegate)方法。

通过将以下内容添加到委托(delegate)方法中的代码顶部来解决此问题:

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