Struct TreeState 

pub struct TreeState {
    pub expanded: HashSet<usize>,
    pub scroll_state: ScrollListState,
}

State for the Tree widget.

Fields

expanded: HashSet<usize>

Set of node ids that are currently expanded.

scroll_state: ScrollListState

Implementations

impl TreeState

pub fn toggle(&mut self, id: usize)

pub fn expand_all(&mut self, nodes: &[TreeNode<'_>])

Expand all nodes that have children.

pub fn expand_subtree(&mut self, nodes: &[TreeNode<'_>], id: usize)

Expand this node and all its descendants recursively.

pub fn collapse_at(&mut self, nodes: &[TreeNode<'_>], cursor_id: usize)

Collapse from cursor position.

If the cursor is on an expanded node with children → collapse that node. Otherwise find the nearest expanded ancestor and collapse it.

pub fn expand_at(&mut self, nodes: &[TreeNode<'_>], cursor_id: usize)

Expand from cursor position.

If cursor is on a collapsed node → expand just that node. If cursor is on an already-expanded node → expand the entire subtree recursively.

pub fn nearest_expanded_ancestor( &self, nodes: &[TreeNode<'_>], cursor_id: usize, ) -> Option<usize>

Find the nearest ancestor of cursor_id that is currently expanded, walking from the root downward. Returns None if no ancestor is expanded.

pub fn visible_index_of( &self, nodes: &[TreeNode<'_>], target_id: usize, ) -> Option<usize>

Return the visible item index of the first node with id, or None if it’s hidden behind a collapsed ancestor.

pub fn walk<'b>( nodes: &'b [TreeNode<'b>], target_id: usize, expanded: &HashSet<usize>, visible: bool, idx: &mut usize, ) -> Option<usize>

Trait Implementations

impl Clone for TreeState

fn clone(&self) -> TreeState

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for TreeState

fn default() -> TreeState

Returns the “default value” for a type.