Tree

A virtualized hierarchical list with explicit expansion and selection state.

Like every gpui-base primitive, Tree supplies behavior and semantic structure without imposing a product visual language. Apply GPUI styles and compose the exported parts to match your design system.

Example

The single native Cargo entrypoint selects this primitive from the shared showcase implementation. The same showcase is compiled once for the WASM preview above.

cargo run -p gpui-base --example components -- tree

Import

use gpui_base::{Tree, TreeItem, TreeState};

Anatomy and API

The example composes Tree, TreeItem, TreeState. GPUI's standard styling and event traits provide presentation; these base types provide the interaction structure.

The authoritative module is components/tree.rs. Native and browser previews compile this same file.

State and events

TreeState owns items, expansion, and selection; tree actions update that entity.

Keep controlled state on the parent render type or in a GPUI entity. Update it in callbacks and call cx.notify(); do not recreate persistent entities during every render.

Complete Rust example

The complete implementation used by the runnable showcase is embedded directly from Rust source:

use super::*;
use gpui::{Image, ImageFormat, StyleRefinement, img};
use std::sync::Arc;

const CHEVRON_RIGHT_SVG: &[u8] = br##"<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16" fill="none"><path d="m6 3.5 4.5 4.5L6 12.5" stroke="#171717" stroke-width="1.5" stroke-linecap="square" stroke-linejoin="miter"/></svg>"##;
const CHEVRON_DOWN_SVG: &[u8] = br##"<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16" fill="none"><path d="m3.5 6 4.5 4.5L12.5 6" stroke="#171717" stroke-width="1.5" stroke-linecap="square" stroke-linejoin="miter"/></svg>"##;

impl BaseShowcase {
    pub(in super::super) fn tree(&self) -> impl IntoElement {
        Tree::new(&self.tree)
            .w_64()
            .h_48()
            .list_style(StyleRefinement::default().flex_grow_1().size_full())
            .relative()
            .text_sm()
            .border_1()
            .border_color(super::example_rgb(0xd4d4d4))
            .py_1()
            .item(|_, entry, state, _, _| {
                let depth = entry.depth();
                let icon = entry.is_folder().then(|| {
                    let bytes = if entry.is_expanded() {
                        CHEVRON_DOWN_SVG
                    } else {
                        CHEVRON_RIGHT_SVG
                    };
                    img(Arc::new(Image::from_bytes(
                        ImageFormat::Svg,
                        bytes.to_vec(),
                    )))
                    .size_3()
                    .flex_none()
                });
                div()
                    .h_8()
                    .mx_1()
                    .px_2()
                    .flex()
                    .items_center()
                    .gap_1()
                    .when(state.is_selected(), |this| {
                        this.bg(super::example_rgb(0xf0f0f0))
                    })
                    .when(depth > 0, |this| {
                        this.child(div().flex_none().w(px(depth as f32 * 12.)))
                    })
                    .child(
                        div()
                            .size_3()
                            .flex_none()
                            .flex()
                            .items_center()
                            .justify_center()
                            .children(icon),
                    )
                    .child(entry.item().label.clone())
                    .into_any_element()
            })
    }
}

The command above supplies application initialization, window creation, and shared BaseShowcase state.

Accessibility

Expose hierarchy, level, expansion, and selection; preserve keyboard movement and visible focus.

Notes

Use stable element IDs where accepted. Verify focus, hover, active, selected, disabled, reduced-motion, and high-contrast appearances in the consuming design system.