Koiusa File Picker

Provides coroutine-based APIs for opening files, choosing save destinations, and exporting documents in Unity Editor, Windows, macOS, and iOS. Application-specific processing such as archive extraction is intentionally handled by the consuming project.

Dependencies

• Unity 6000.3 or newer
• No additional UPM package dependencies

Opening a file

var request = FilePicker.Pick(new FilePickerOptions
{
    Title = "Select model",
    InitialDirectory = directory,
    Filters = new[] { new FilePickerFilter("MMD model", "pmx", "pmd") }
});

yield return request;

if (request.Status == FilePickerStatus.Selected)
    Debug.Log(request.Path);
else if (request.Status == FilePickerStatus.Failed)
    Debug.LogException(request.Error);

Saving a file

Save uses the same FilePickerRequest and FilePickerStatus coroutine pattern as Pick. On Windows, macOS, and in the Unity Editor, callers can request only a destination and write after selection:

var request = FilePicker.Save(new FilePickerSaveOptions
{
    Title = "Export configuration",
    InitialDirectory = directory,
    SuggestedFileName = "offaxisprojection.json",
    DefaultExtension = "json",
    Filters = new[] { new FilePickerFilter("JSON configuration", "json") }
});

yield return request;

if (request.Status == FilePickerStatus.Selected)
    ExportConfiguration(request.Path);
else if (request.Status == FilePickerStatus.Failed)
    Debug.LogException(request.Error);

Native save dialogs confirm replacement of existing files, do not change the process current directory, and remember the last selected directory.

Writing or exporting through the request

Set WriteToStream to let the request perform the write, or set SourcePath to export an existing file. These properties are optional on desktop and in the Editor. Do not specify both.

var request = FilePicker.Save(new FilePickerSaveOptions
{
    SuggestedFileName = "configuration.json",
    DefaultExtension = "json",
    WriteToStream = stream => WriteConfiguration(stream)
});

yield return request;

iOS does not expose an arbitrary writable destination path. Consequently, iOS requires either WriteToStream or SourcePath and presents the platform's standard document export picker. A successful request means the prepared document was exported; callers must not attempt to write to the returned path.

Status and compatibility

Both operations return FilePickerRequest with one of these states:

• Pending: the operation is still running
• Selected: a file or destination was selected, or an iOS export completed
• Cancelled: the user dismissed the dialog
• Failed: the operation failed; details are available through Error

The public entry point remains the single FilePicker facade. Open and save options and provider contracts are separate, so existing implementations of IFilePickerProvider remain source-compatible. Providers that support saving additionally implement IFilePickerSaveProvider.

File library

FileLibrary provides an optional persistent library of categorized file references. On iOS it imports files into persistentDataPath; a configurable category can import a directory tree to preserve sidecar resources. Pass directoryImportRoot when the directory to preserve is above the selected file's immediate parent (for example, the root of an extracted model archive). The selected file's relative path within that root is retained in the imported library entry.