Trait IntoMsg

Source

pub trait IntoMsg<Msg>: Sized {
    // Required method
    fn defer(work: impl Fn() -> Self + 'static) -> Msg;
}

Expand description

What a handler’s result can be turned into, so a widget’s setter takes both shapes: a closure that returns the widget’s message type, and — in an application built from components — one that just does the work and returns nothing.

let checked = Rc::new(Cell::new(false));
let flag = checked.clone();
// the closure does the work; there is no message to return
let _box: Checkbox = Checkbox::new(false).on_toggle(move |on| flag.set(on));

A closure that returns () becomes a message that runs it: the work waits for the message to be delivered, not for it to be made, because a widget may ask for its message more than once for one interaction. Anything else is its own message, made at once.