Struct FocusManager 

pub struct FocusManager<Id> { /* private fields */ }

Manages keyboard focus across multiple components.

FocusManager is generic over an ID type, which is typically a user-defined enum representing the focusable elements in your application. It tracks which element is currently focused and provides methods for navigation.

Type Parameters

• Id: The type used to identify focusable elements. Must implement Clone and PartialEq.

Navigation Behavior

• focus_next() moves focus forward, wrapping from last to first
• focus_prev() moves focus backward, wrapping from first to last
• When unfocused, focus_next() focuses the first item, focus_prev() focuses the last

Implementations

impl<Id: Clone + PartialEq> FocusManager<Id>

pub fn new(order: Vec<Id>) -> Self

Creates a new focus manager with the given focus order.

The manager starts with no element focused. Use with_initial_focus to start with the first element focused.

Example

use envision::component::FocusManager;

let focus: FocusManager<&str> = FocusManager::new(vec!["a", "b", "c"]);
assert_eq!(focus.focused(), None);

pub fn with_initial_focus(order: Vec<Id>) -> Self

Creates a new focus manager with the first element focused.

If the order is empty, no element will be focused.

Example

use envision::component::FocusManager;

let focus = FocusManager::with_initial_focus(vec!["a", "b", "c"]);
assert_eq!(focus.focused(), Some(&"a"));

pub fn focused(&self) -> Option<&Id>

Returns the currently focused ID, if any.

Example

use envision::component::FocusManager;

let mut focus = FocusManager::new(vec!["a", "b"]);
assert_eq!(focus.focused(), None);

focus.focus(&"a");
assert_eq!(focus.focused(), Some(&"a"));

pub fn is_focused(&self, id: &Id) -> bool

Returns true if the given ID is currently focused.

Example

use envision::component::FocusManager;

let focus = FocusManager::with_initial_focus(vec!["a", "b"]);
assert!(focus.is_focused(&"a"));
assert!(!focus.is_focused(&"b"));

pub fn focus(&mut self, id: &Id) -> bool

Focuses a specific ID.

Returns true if the ID was found and focused, false if the ID is not in the focus order.

Example

use envision::component::FocusManager;

let mut focus = FocusManager::new(vec!["a", "b", "c"]);

assert!(focus.focus(&"b"));
assert_eq!(focus.focused(), Some(&"b"));

assert!(!focus.focus(&"unknown"));
assert_eq!(focus.focused(), Some(&"b")); // Unchanged

pub fn focus_next(&mut self) -> Option<&Id>

Moves focus to the next item in the order.

If no item is currently focused, focuses the first item. Wraps from the last item to the first.

Returns the newly focused ID, or None if the order is empty.

Example

use envision::component::FocusManager;

let mut focus = FocusManager::with_initial_focus(vec!["a", "b", "c"]);

assert_eq!(focus.focus_next(), Some(&"b"));
assert_eq!(focus.focus_next(), Some(&"c"));
assert_eq!(focus.focus_next(), Some(&"a")); // Wraps

pub fn focus_prev(&mut self) -> Option<&Id>

Moves focus to the previous item in the order.

If no item is currently focused, focuses the last item. Wraps from the first item to the last.

Returns the newly focused ID, or None if the order is empty.

Example

use envision::component::FocusManager;

let mut focus = FocusManager::with_initial_focus(vec!["a", "b", "c"]);

assert_eq!(focus.focus_prev(), Some(&"c")); // Wraps from first to last
assert_eq!(focus.focus_prev(), Some(&"b"));
assert_eq!(focus.focus_prev(), Some(&"a"));

pub fn blur(&mut self)

Removes focus entirely.

After calling this, focused() will return None.

Example

use envision::component::FocusManager;

let mut focus = FocusManager::with_initial_focus(vec!["a", "b"]);
assert!(focus.focused().is_some());

focus.blur();
assert!(focus.focused().is_none());

pub fn focus_first(&mut self) -> Option<&Id>

Focuses the first item in the order.

Returns the focused ID, or None if the order is empty.

Example

use envision::component::FocusManager;

let mut focus = FocusManager::new(vec!["a", "b", "c"]);
focus.focus(&"c");

assert_eq!(focus.focus_first(), Some(&"a"));
assert_eq!(focus.focused(), Some(&"a"));

pub fn focus_last(&mut self) -> Option<&Id>

Focuses the last item in the order.

Returns the focused ID, or None if the order is empty.

Example

use envision::component::FocusManager;

let mut focus = FocusManager::new(vec!["a", "b", "c"]);

assert_eq!(focus.focus_last(), Some(&"c"));
assert_eq!(focus.focused(), Some(&"c"));

pub fn order(&self) -> &[Id]

Returns the focus order.

Example

use envision::component::FocusManager;

let focus = FocusManager::new(vec!["a", "b", "c"]);
assert_eq!(focus.order(), &["a", "b", "c"]);

pub fn is_empty(&self) -> bool

Returns true if the focus order is empty.

Example

use envision::component::FocusManager;

let empty: FocusManager<&str> = FocusManager::default();
assert!(empty.is_empty());

let non_empty = FocusManager::new(vec!["a"]);
assert!(!non_empty.is_empty());

pub fn len(&self) -> usize

Returns the number of items in the focus order.

Example

use envision::component::FocusManager;

let focus = FocusManager::new(vec!["a", "b", "c"]);
assert_eq!(focus.len(), 3);

Trait Implementations

impl<Id: Clone> Clone for FocusManager<Id>

fn clone(&self) -> FocusManager<Id>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<Id: Debug> Debug for FocusManager<Id>

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

Formats the value using the given formatter.

impl<Id> Default for FocusManager<Id>

fn default() -> Self

Returns the “default value” for a type.