FilePicker.platform.saveFile(...) doesn't save a file on Linux, but does on Android (emulator)

[aiurovet]

I'm developing a Flutter application that saves images to external storage as one of its activities. When I use an Android emulator, FilePicker.platform.saveFile allows selecting a folder and a filename, then saves data (parameter bytes) there. But when I run the Linux app (my dev machine is running Kubuntu 25.04), I select a folder and a filename, no exception is thrown, everything looks good, but the file is not there (or not overwritten if it existed before). When googling a solution, the AI-generated result mentioned that I have to save the file myself: await File(path).writeAsBytes(bytes);

So, at the moment, I'm passing Uint8List(0) as bytes to FilePicker.platform.saveFile(...), then saving as above.

But why is it asymmetric? And what's the point of requiring a non-null array of bytes if it is not always used?

Package version: 10.3.3 (at the moment, the latest).

Platform: Desktop (Linux)

Platform OS version: Kubuntu 25.04

How are you picking?

      var outFilePath = await FilePicker.platform.saveFile(
        dialogTitle: 'Save Image As',
        type: FileType.image,
        allowedExtensions: ['png',],
        fileName: 'test.png',
        bytes: bytes, // obtained before
      );

Details to reproduce the issue: just confirm it works under every target platform the same way.

[maurovanetti]

Exactly same situation for me in a Linux environment, with a .txt file though (FileType.custom). The same code works properly for a web build but it just launches a download instead of path picking.

This workaround saved my day: if (!kIsWeb) await File(path).writeAsBytes(bytes); (thank you!)

[aiurovet]

@maurovanetti, thank you too. It's an interesting case I overlooked. You are right: there is no need to save the file separately in case of a web app.

[github-actions]

This issue is stale because it has been open for 7 days with no activity.