Struct State 

pub struct State<T: Copy> { /* private fields */ }

Reactive integer state backed by LVGL’s observer subsystem (lv_subject_t). Bind widget properties to a State and they update automatically when you call State::set.

Stability requirement

lv_subject_t keeps a linked list of observer references, so the State address must be stable from the moment any observer attaches. The intended usage is inside a static slot — either a raw static declared by the user, or via the ove::shared! macro. Dropping a State while observers are still attached will corrupt the observer list. PhantomPinned prevents move after construction.

use ove::lvgl::{State, Label};
ove::shared!(COUNTER: State<i32>);
// init once:
COUNTER.init(State::new(0));
// bind:
Label::create(screen).bind_text(COUNTER.get_ref(), b"Count: %d\0");
// update from anywhere:
COUNTER.get_ref().set(42);  // label updates automatically

Implementations

impl<T: Copy + Into<i32> + TryFrom<i32>> State<T>

pub fn new(initial: T) -> Self

Create a new reactive state with an initial value.

pub fn set(&self, value: T)

Set a new value. All bound widgets update immediately.

Takes &self rather than &mut self because LVGL serializes observer notification under the global LVGL lock — the lock is the real mutex, not Rust’s borrow checker.

pub fn get(&self) -> T

Read the current value. Falls back to a zeroed T if the stored i32 cannot be converted back to T (unreachable for well-typed integer states).

pub fn subject_ptr(&self) -> *mut lv_subject_t

Returns the raw *mut lv_subject_t for widget binding.

impl<T: Copy + Into<i32> + TryFrom<i32>> State<T>

pub fn observe(&self, obj: impl Widget)

Attach an observer that automatically refreshes obj when this state changes. The actual rebinding logic is on the widget side (e.g. Label::bind_text) — this is a low-level escape hatch.

Trait Implementations

impl<T: Copy> Drop for State<T>

fn drop(&mut self)

Executes the destructor for this type.

impl<T: Copy + Send> Send for State<T>

impl<T: Copy + Send> Sync for State<T>