Module tree 

Available on crate feature tree only.

Hierarchical items that expand and collapse, such as folders and files.

State holds the nodes keyed by id, which are expanded, and the selection. Its update handles expanding, pointer and keyboard selection in the chosen Mode, checkboxes with tri-state parents, and children that load later. The view only builds the rows of expanded nodes that are in view, so a tree of thousands of nodes stays quick.

A node made with Node::lazy has children that are not loaded yet. Expanding it marks it loading and returns Output::Load; the app fetches the children and sends them back through the channel that subscription owns, as Loaded batches.

The tree resolves its keys through a Keymap of Actions while it has focus, which it takes when pressed; see default_keymap. Letters and digits jump to the next node starting with them.

Structs

Loaded

Children that arrived for a lazy node.

Node

One node: its label and look. Its children are given with children, or later with Node::lazy.

RowStyle

The colours of a row.

State

The nodes, their structure and what is expanded, selected and checked.

Status

How a row is shown.

Tree

A tree builder. Convert it into an Element to render.

Enums

Action

What a tree keyboard shortcut does.

Event

Everything that changes a tree.

Mode

How nodes are selected.

Output

What the app may need to act on after an Event.

Trailing

What sits at the end of a row.

Constants

BATCH_SIZE

The most batches delivered in one Event::Received.

CHANNEL_CAPACITY

How many loaded batches a producer can send before it has to wait.

INDENT

Width of one level of indentation, which is also the chevron’s slot.

ROW_HEIGHT

Height of every row, as in a menu.

Functions

default_keymap

The default tree shortcuts:

guide_colour

The colour of the indentation guides.

loaded

The children of parent, to send through the channel.

node

Creates a leaf node.

row_style

Resolves a row’s colours from the shared menu rows: a selected row is drawn as a highlighted menu row, and a hovered one with a lighter tint.

stream

The stream behind subscription, for driving it without a runtime.

subscription

Owns the channel lazy children arrive on. Emits Event::Ready first, then batches.

tree

Renders state. Without on_event every row renders disabled.

Type Aliases

Sender

The sending half of the channel lazy children arrive on. Clone it for each producer.