选择器的配置不是有效的配置，Swift

Question

我正在开发由苹果公司在WWDC2020中提供的名为PHPicker的新图像选择API。当我第二次从选择器中选择图像时，我会得到这个错误。当代码第一次完美地工作时。第二次单击按钮打开选择器时，应用程序崩溃时会出现以下错误。“由于异常'NSInternalInconsistencyException‘终止应用程序，原因：’选择器的配置不是一个有效的配置.‘”。

 @IBAction func addVideo(_ sender: UIButton) {
        presentPicker(filter: .videos)
  }

 private func presentPicker(filter: PHPickerFilter?) {
        var configuration = PHPickerConfiguration(photoLibrary: .shared())
        
        // Set the filter type according to the user’s selection.
        configuration.filter = filter
        // Set the mode to avoid transcoding, if possible, if your app supports arbitrary image/video encodings.
        configuration.preferredAssetRepresentationMode = .current
        // Set the selection behavior to respect the user’s selection order.
        configuration.selection = .ordered
        // Set the selection limit to enable multiselection.
        configuration.selectionLimit = 1
        // Set the preselected asset identifiers with the identifiers that the app tracks.
        configuration.preselectedAssetIdentifiers = selectedAssetIdentifiers
        
        let picker = PHPickerViewController(configuration: configuration)
        picker.delegate = self
        present(picker, animated: true)
    }


func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
        dismiss(animated: true)
        
        let existingSelection = self.selection
        var newSelection = [String: PHPickerResult]()
        for result in results {
            let identifier = result.assetIdentifier!
            newSelection[identifier] = existingSelection[identifier] ?? result
        }
        
        // Track the selection in case the user deselects it later.
        selection = newSelection
        selectedAssetIdentifiers = results.map(\.assetIdentifier!)
        selectedAssetIdentifierIterator = selectedAssetIdentifiers.makeIterator()
        
        if selection.isEmpty {
            displayEmptyImage()
        } else {
            displayImage()
        }
    }

我使用的代码与苹果在他们的网站上提供的代码相同。https://developer.apple.com/documentation/photokit/phpickerviewcontroller。我刚刚把selectionLimit从0改为1。

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Answer 1

显然，只有当preselectedAssetIdentifiers大于1 (这是默认的)时，preselectedAssetIdentifiers属性才是有效的(开玩笑的，只是在头文件中)。

以下是Apple论坛的回答，供参考：https://developer.apple.com/forums/thread/705493

Answer 2

您的代码一定有问题。我已经复制粘贴了您的解决方案，它在模拟器(iOS 15.0)上正确工作。