Struct LaunchedEffectScope 

pub struct LaunchedEffectScope { /* private fields */ }

The scope a LaunchedEffect receives: the effect’s coroutine scope.

The effect is cancelled when its keys change or its call site leaves the composition. The cancellation drops the effect’s future where it waits. No line after that .await runs. The cancellation also cancels every task the scope launched.

Implementations

impl LaunchedEffectScope

pub fn is_active(&self) -> bool

Returns true until the effect is cancelled. The effect is cancelled when its keys change or its call site leaves the composition.

pub fn runtime(&self) -> RuntimeHandle

Returns a handle to the runtime that runs the effect.

pub async fn with_frame_nanos<R>(&self, on_frame: impl FnOnce(u64) -> R) -> R

Waits for the next frame, then calls on_frame with the frame time in nanoseconds and returns what it returns. Compose’s withFrameNanos. Await it in a loop to run once per frame:

LaunchedEffect((), async move |scope| loop {
    scope.with_frame_nanos(|nanos| time.set(nanos)).await;
});

pub async fn with_frame_millis<R>(&self, on_frame: impl FnOnce(u64) -> R) -> R

Waits for the next frame, then calls on_frame with the frame time in milliseconds and returns what it returns. Compose’s withFrameMillis.

pub fn launch(&self, future: impl Future<Output = ()> + 'static)

Launches future on the UI thread as a child of the effect, as Compose’s launch inside a LaunchedEffect does: the effect’s cancellation cancels it too.

pub fn launch_background<T, Work, Ui, Fut>(&self, work: Work, on_ui: Ui)

where T: Send + 'static, Work: FnOnce(CancelToken) -> Fut + Send + 'static, Fut: Future<Output = T> + Send + 'static, Ui: FnOnce(T) + 'static,

Runs background work and delivers results to the UI.

On native targets, work runs on a worker thread. Its future runs to completion there. The on_ui continuation runs on the runtime thread. It may capture Rc and RefCell state. It does not run once the effect is cancelled.

Trait Implementations

impl Clone for LaunchedEffectScope

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.