pub type ItemExtentBuilder = Rc<dyn Fn(i32, SliverLayoutDimensions) -> Option<f64>>;Expand description
Signature for a callback that reports the main-axis extent of the item at index.
Used by ListView.itemExtentBuilder and SliverVariedExtentList.itemExtentBuilder.
Dart compares two builders with ==; an Rc compares by pointer.
Aliased Typeยง
pub struct ItemExtentBuilder { /* private fields */ }