Struct ListState 

pub struct ListState {
    pub selected: Option<usize>,
    pub hovered: Option<usize>,
    pub offset: usize,
    /* private fields */
}

Mutable state for a List widget tracking selection and scroll offset.

Fields

selected: Option<usize>

Index of the currently selected item, if any.

hovered: Option<usize>

Index of the currently hovered item, if any.

offset: usize

Scroll offset (first visible item index).

Implementations

impl ListState

pub fn select(&mut self, index: Option<usize>)

Set the selected item index, or None to deselect.

pub fn selected(&self) -> Option<usize>

Return the currently selected item index.

pub fn with_persistence_id(self, id: impl Into<String>) -> Self

Create a new ListState with a persistence ID for state saving.

pub fn persistence_id(&self) -> Option<&str>

Get the persistence ID, if set.

pub fn handle_mouse( &mut self, event: &MouseEvent, hit: Option<(HitId, HitRegion, u64)>, expected_id: HitId, item_count: usize, ) -> MouseResult

Handle a mouse event for this list.

Hit data convention

The hit data (u64) encodes the item index. When the list renders with a hit_id, each visible row registers HitRegion::Content with data = item_index as u64.

Arguments

• event — the mouse event from the terminal
• hit — result of frame.hit_test(event.x, event.y), if available
• expected_id — the HitId this list was rendered with
• item_count — total number of items in the list

pub fn scroll_up(&mut self, lines: usize)

Scroll the list up by the given number of lines.

pub fn scroll_down(&mut self, lines: usize, item_count: usize)

Scroll the list down by the given number of lines.

Clamps so that the last item can still appear at the top of the viewport.

pub fn select_next(&mut self, item_count: usize)

Move selection to the next item.

If nothing is selected, selects the first item. Clamps to the last item.

pub fn select_previous(&mut self)

Move selection to the previous item.

If nothing is selected, selects the first item. Clamps to 0.

impl ListState

pub fn undo_id(&self) -> UndoWidgetId

Get the undo widget ID.

This can be used to associate undo commands with this state instance.

Trait Implementations

impl Clone for ListState

fn clone(&self) -> ListState

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ListState

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ListState

fn default() -> Self

Returns the “default value” for a type.

impl ListUndoExt for ListState

fn selected_index(&self) -> Option<usize>

Get the current selection.

fn set_selected_index(&mut self, index: Option<usize>)

Set the selection.

impl Stateful for ListState

type State = ListPersistState

The state type that gets persisted.

fn state_key(&self) -> StateKey

Unique key identifying this widget instance.

fn save_state(&self) -> ListPersistState

Extract current state for persistence.

fn restore_state(&mut self, state: ListPersistState)

Restore state from persistence.

fn state_version() -> u32

State schema version for forward-compatible migrations.

impl UndoSupport for ListState

fn undo_widget_id(&self) -> UndoWidgetId

Get the widget’s unique ID for undo tracking.

fn create_snapshot(&self) -> Box<dyn Any + Send>

Create a snapshot of the current state for undo purposes.

fn restore_snapshot(&mut self, snapshot: &dyn Any) -> bool

Restore state from a snapshot.