Struct LazyListController 

pub struct LazyListController { /* private fields */ }

Persistent state for lazy list components.

This controller holds both the scroll position (ScrollableController) and the item measurement cache. When retained across navigation (via retain or retain_with_key), both the scroll position and cached measurements will be preserved, ensuring correct layout when remounting.

Examples

use tessera_components::lazy_list::{LazyListController, lazy_column};
use tessera_ui::{LayoutResult, retain_with_key, tessera};

#[tessera]
fn scrollable_page(page_id: String) {
    // Both scroll position and measurement cache persist across navigation
    let controller = retain_with_key(page_id.clone(), LazyListController::new);
    lazy_column().controller(controller).items(100, |i| {
        let _ = i;
    });
}

Implementations

impl LazyListController

pub fn new() -> Self

Creates a new lazy list controller with default scroll position and empty cache.

pub fn scroll_controller(&self) -> &ScrollableController

Returns a reference to the underlying scroll controller.

pub fn scroll_controller_mut(&mut self) -> &mut ScrollableController

Returns a mutable reference to the underlying scroll controller.

pub fn scroll_to(&mut self, x: Dp, y: Dp)

Scrolls to content offsets from the start of each axis, in logical pixels.

The request is applied once when the list next builds. Subsequent wheel and drag input continues from that position.

pub fn scroll_to_item(&mut self, index: usize, offset: Dp)

Reveals an item at an offset from the viewport start.

Earlier unmeasured items use the list estimate. The requested item is composed and measured before its final visible placement is published. Requests outside the current item range are ignored. Later wheel input continues from the request rather than being overwritten by it.

Panics

Panics if offset is not finite.

Trait Implementations

impl Default for LazyListController

fn default() -> Self

Returns the “default value” for a type.