Trait OverflowObserver 

pub trait OverflowObserver {
    // Required method
    fn measured(&self, metrics: ContentMetrics);

    // Provided method
    fn overflow_pressed(&self) { ... }
}

The layout-time content-measurement seam: handed the ContentMetrics of every layout pass, including whether the label overflowed.

Measurement only — deliberately no return value, so an observer cannot steer layout from inside it. The strategies that react to an overflow (scroll, popup, bottom sheet) are a follow-up; this is the signal they subscribe to.

Required Methods

fn measured(&self, metrics: ContentMetrics)

Called at the end of each of the button’s layout passes.

Provided Methods

fn overflow_pressed(&self)

Called instead of firing the normal on_press when a press lands on an overflowing button whose super::OverflowStrategy is super::OverflowStrategy::BottomSheet — the hook an app shows its own bottom sheet from (see that variant’s doc for why the widget cannot do so itself). Defaulted to a no-op, mirroring Self::measured’s own “install nothing, behave as if this trait did not exist” shape.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors