就我了解到的您的需求而言，FilesProvider有一个API，您可以通过其他应用程序与它交互，
了解更多信息here
这是一个很好的教程here
这将使您很好地了解API的工作原理以及FileProvider在iOS中的工作原理

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从以上链接复制
iOS 14已弃用此方法

public init(documentTypes allowedUTIs: [String], in mode: UIDocumentPickerMode)

在按钮操作中编写此代码

@IBAction func importItemFromFiles(sender: UIBarButtonItem) {

     var documentPicker: UIDocumentPickerViewController!
     if #available(iOS 14, *) {
         // iOS 14 & later
         let supportedTypes: [UTType] = [UTType.image]
         documentPicker = UIDocumentPickerViewController(forOpeningContentTypes: supportedTypes)
     } else {
         // iOS 13 or older code
         let supportedTypes: [String] = [kUTTypeImage as String]
         documentPicker = UIDocumentPickerViewController(documentTypes: supportedTypes, in: .import)
     }
     documentPicker.delegate = self
     documentPicker.allowsMultipleSelection = true
     documentPicker.modalPresentationStyle = .formSheet
     self.present(documentPicker, animated: true)
 }

实作委派

// MARK: - UIDocumentPickerDelegate Methods

  extension MyViewController: UIDocumentPickerDelegate {
    func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {

        for url in urls {

            // Start accessing a security-scoped resource.
            guard url.startAccessingSecurityScopedResource() else {
                // Handle the failure here.
                return
            }

            do {
                let data = try Data.init(contentsOf: url)
                // You will have data of the selected file
            }
            catch {
                print(error.localizedDescription)
            }

            // Make sure you release the security-scoped resource when you finish.
            defer { url.stopAccessingSecurityScopedResource() }
        }
    }

    func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {
        controller.dismiss(animated: true, completion: nil)
    }
}