Struct TreePiece 

pub struct TreePiece<S: NodeSource> { /* private fields */ }

Implementations

impl<S: NodeSource + 'static> TreePiece<S>

pub fn row_height(self, h: RowHeight) -> Self

Row sizing: Uniform(h) (fastest) or Automatic (self-sizing).

pub fn indent(self, pts: f64) -> Self

Indentation per depth level, in points (unset = the platform’s default step).

pub fn section_headers(self) -> Self

Render a two-level source as sections. Root branches are headings and cannot be selected; root leaves remain ordinary rows. Children must be leaves. This enables native ExpandableListView on Android, where arbitrary-depth trees are composed.

pub fn on_expansion(self, f: impl Fn(S::Key, bool) + 'static) -> Self

Reports an actual user/scripting disclosure change with the stable application key. Programmatic writes to expanded do not echo this callback.

pub fn expanded(self, set: impl Binding<HashSet<S::Key>>) -> Self

The app-owned expansion set (docs/tree.md): the user’s disclosure clicks update it, and the app writing it discloses/collapses the native rows. Persist it (or don’t); it is plain state.

pub fn expandable(self, f: impl Fn(&S::Key) -> bool + 'static) -> Self

Which rows can hold children at all: what draws (or omits) the disclosure, and which rows a drop may land on. Defaults to “has children right now”, which draws no disclosure on an empty group; a source with real branch/leaf kinds should say so.

pub fn selected(self, f: impl Fn() -> Vec<S::Key> + 'static) -> Self

Reactively sync the native selection to these keys (empty clears). Point it and Self::on_selection at one signal and selection is two-way, shared with anything else reading the same state.

pub fn on_selection(self, f: impl Fn(Vec<S::Key>) + 'static) -> Self

Called with the full selected key set (empty = cleared) whenever the user changes the selection.

pub fn multi_select(self) -> Self

Allow selecting several rows at once, where the toolkit supports it.

pub fn movable(self, mv: Move<S::Key>) -> Self

Let the user drag rows to a new parent/position with the platform’s native mechanism, where the backend supports it (probe Cap::TreeMove): the tree is movable exactly when it carries a Move, whose handler re-parents the app’s data.

tree(nodes, row_view).movable(Move::new(move |key, parent, index| store.reparent(key, parent, index)))

pub fn type_ahead(self, f: impl Fn(&S::Key) -> String + 'static) -> Self

The row’s type-ahead string (docs/tree.md): what native type-select matches against. Unset rows don’t participate.

pub fn reveal(self, target: impl Binding<Option<S::Key>>) -> Self

Programmatic reveal: set the signal to Some(key) and the row scrolls into view with every ancestor expanded (through Self::expanded, so the app sees the change).

pub fn row_id(self, f: impl Fn(&S::Key) -> ElementId + 'static) -> Self

A dayscript element id per row, from its key (docs/tree.md): re-applied on every recycle, so tap/assert_text address the row wherever its cell currently sits. It is also what the expand:/tree_move: steps resolve rows by.

pub fn row_context_menu( self, f: impl Fn(&S::Key) -> Vec<MenuEntry> + 'static, ) -> Self

A per-row context menu, built when the menu is summoned (docs/menus.md “Dynamic context menus”): right-click on desktop, long-press on touch. The closure receives the row’s key and returns the menu to show; it may adjust the app’s selection first (the convention: a summon outside the current selection selects that row). An empty result shows nothing for that row.

Trait Implementations

impl<S: NodeSource + 'static> Piece for TreePiece<S>

fn build(self, cx: &mut BuildCx) -> RNode

impl<S: NodeSource + 'static> TreeBuilder<S> for TreePiece<S>

fn row_height(self, h: RowHeight) -> Self

Row sizing: Uniform(h) (fastest) or Automatic (self-sizing).

fn indent(self, pts: f64) -> Self

Indentation per depth level, in points (unset = the platform’s default step).

fn section_headers(self) -> Self

Render a two-level source as sections. Root branches are headings and cannot be selected; root leaves remain ordinary rows. Children must be leaves. This enables native ExpandableListView on Android, where arbitrary-depth trees are composed.

fn on_expansion(self, f: impl Fn(S::Key, bool) + 'static) -> Self

Reports an actual user/scripting disclosure change with the stable application key. Programmatic writes to expanded do not echo this callback.

fn expanded(self, set: impl Binding<HashSet<S::Key>>) -> Self

The app-owned expansion set (docs/tree.md): the user’s disclosure clicks update it, and the app writing it discloses/collapses the native rows. Persist it (or don’t); it is plain state.

fn expandable(self, f: impl Fn(&S::Key) -> bool + 'static) -> Self

Which rows can hold children at all: what draws (or omits) the disclosure, and which rows a drop may land on. Defaults to “has children right now”, which draws no disclosure on an empty group; a source with real branch/leaf kinds should say so.

fn selected(self, f: impl Fn() -> Vec<S::Key> + 'static) -> Self

Reactively sync the native selection to these keys (empty clears). Point it and Self::on_selection at one signal and selection is two-way, shared with anything else reading the same state.

fn on_selection(self, f: impl Fn(Vec<S::Key>) + 'static) -> Self

Called with the full selected key set (empty = cleared) whenever the user changes the selection.

fn multi_select(self) -> Self

Allow selecting several rows at once, where the toolkit supports it.

fn movable(self, mv: Move<S::Key>) -> Self

Let the user drag rows to a new parent/position with the platform’s native mechanism, where the backend supports it (probe Cap::TreeMove): the tree is movable exactly when it carries a Move, whose handler re-parents the app’s data.

fn type_ahead(self, f: impl Fn(&S::Key) -> String + 'static) -> Self

The row’s type-ahead string (docs/tree.md): what native type-select matches against. Unset rows don’t participate.

fn reveal(self, target: impl Binding<Option<S::Key>>) -> Self

Programmatic reveal: set the signal to Some(key) and the row scrolls into view with every ancestor expanded (through Self::expanded, so the app sees the change).

fn row_id(self, f: impl Fn(&S::Key) -> ElementId + 'static) -> Self

A dayscript element id per row, from its key (docs/tree.md): re-applied on every recycle, so tap/assert_text address the row wherever its cell currently sits. It is also what the expand:/tree_move: steps resolve rows by.

fn row_context_menu( self, f: impl Fn(&S::Key) -> Vec<MenuEntry> + 'static, ) -> Self

A per-row context menu, built when the menu is summoned (docs/menus.md “Dynamic context menus”): right-click on desktop, long-press on touch. The closure receives the row’s key and returns the menu to show; it may adjust the app’s selection first (the convention: a summon outside the current selection selects that row). An empty result shows nothing for that row.