使用 Swift 和 iOS 保存文件

Question

I have an iOS app and I need to be able to pick a file on my iCloud Drive, modify the file, and save the modified file with a new extension. I've tried lots of things but I still can't write the new file. Here is my latest code:

documentPickerViewController = DocumentPickerViewController(documentTypes: ["public.item"], in: .open)  

func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {  
    let fileURL = urls[0]  
    do {  
        // Read the file       
        _ = fileURL.startAccessingSecurityScopedResource()  
        let fileData = try Data(contentsOf: fileURL, options: .uncached)  
        fileURL.stopAccessingSecurityScopedResource()  

        // write the file  
        let fileCopyURL = fileURL.appendingPathExtension("copy")  
        _ = fileCopyURL.startAccessingSecurityScopedResource()  
        try fileData.write(to: fileCopyURL)  
        fileCopyURL.stopAccessingSecurityScopedResource()  
    }  
    catch {  
        print(error.localizedDescription)  
    }  
}  

When I pick a file on my iCloud Drive I get the following error:

You don't have permission to save the file “TestFile.txt.copy” in the folder “Test Files”.

How can a save the modified file?

Answer 1

First, I think you should make sure that you have the correct entitlements/permissions to write to iCloud Drive:

If this still doesn't work, try updating the CFBundleVersion or Build Number of your app and make sure that your Bundle Identifier (in the first section of Signing & Capabilities ) is correctly registered on your Apple Developer account.

According to your code, what you're trying to accomplish is feasible but the issue comes from elsewhere.

Let me know if you have an issue following these steps. Good Luck!