TreeItem

TreeItem is the recursive data record used by TreeView.

Each item represents one node in a hierarchy. It can have its own label, optional icon, child items, and selection or expansion actions.

Example

use fission::prelude::*;

let item = TreeItem {
    id: "src".into(),
    icon: None,
    label: "src/".into(),
    children: vec![TreeItem {
        id: "main_rs".into(),
        icon: None,
        label: "main.rs".into(),
        children: vec![],
        on_toggle: None,
        on_select: Some(open_main_file_action),
    }],
    on_toggle: Some(toggle_src_folder_action),
    on_select: Some(select_src_folder_action),
};

Field table

Field	Type	Meaning	Notes / default behavior
id	String	Stable item identifier.	Required. Used by TreeView.expanded_ids and selected_id.
icon	Option<String>	Optional leading icon source.	Defaults to None.
label	String	Visible node label.	Required.
children	Vec<TreeItem>	Child nodes nested under this item.	Defaults to an empty list.
on_toggle	Option<ActionEnvelope>	Intended expansion-toggle action.	Present in the public struct, but see note below.
on_select	Option<ActionEnvelope>	Action fired when the row is selected.	Defaults to None.

Current implementation note

TreeItem exposes on_toggle, but the checked-in TreeView renderer does not currently render a separate expansion affordance or invoke that action for you. Expansion is still reflected through expanded_ids, but the interaction path must be composed carefully at the app level.

Related

TreeView, Breadcrumb, Icon, and Text.