Native integration

Enable host services explicitly. The core domain and visual file components do not require a native picker dependency. Add the optional native feature only in an application that needs it:

slint-kit = { version = "0.1", features = ["native"] }

Requests and outcomes

slint_kit::native::pick_files(FileRequest) and pick_directory(DirectoryRequest) are asynchronous. Construct and poll the picker on the host UI executor, for example slint::spawn_local. Return to a weak window handle when publishing the result. Do not block the UI event loop while awaiting a dialog.

use slint_kit::{FileRequest, FileSelectionMode, SelectionOutcome};

async fn choose_document() -> SelectionOutcome<Vec<slint_kit::FileHandle>> {
    slint_kit::native::pick_files(FileRequest {
        selection: FileSelectionMode::Single,
        filters: Vec::new(),
        suggested_name: None,
    }).await
}

Handle every SelectionOutcome variant: Selected(value), Cancelled, or Failed(HostError). Cancellation preserves the previously accepted selection. HostError::Unsupported is an explicit capability result, not an empty successful selection. Native APIs that cannot distinguish platform failure from cancellation do not fabricate permission errors.

FileFilter::new(label, extensions) validates the filter. FileHandle and DirectoryHandle expose a display name and FileLocation; a location may be Path or Uri. Choosing a resource neither reads its contents nor guarantees that all resources have a filesystem path. File sizes may be unavailable.

Capabilities and pending requests

Check slint_kit::native::capabilities() and project its typed results into KitFilePicker, KitDirectoryPicker and KitFileDropZone. Picker support and external drop support are distinct capabilities. The provided native adapter reports drop support as unsupported; the window backend must supply that integration separately.

HostRequestController<T> issues tickets to reject obsolete asynchronous results. Keep pending, failure and cancellation presentation explicit. See the complete showcase file controller for native request handling and the host adapter for platform behavior.