Struct druid::SingleUse

pub struct SingleUse<T>(_);

A wrapper type for Command payloads that should only be used once.

This is useful if you have some resource that cannot be cloned, and you wish to send it to another widget.

Examples

use druid::{Command, Selector, SingleUse, Target};

struct CantClone(u8);

let selector = Selector::new("use-once");
let num = CantClone(42);
let command = Command::new(selector, SingleUse::new(num), Target::Auto);

let payload: &SingleUse<CantClone> = command.get_unchecked(selector);
if let Some(num) = payload.take() {
    // now you own the data
    assert_eq!(num.0, 42);
}

// subsequent calls will return `None`
assert!(payload.take().is_none());

Implementations

impl<T: Any> SingleUse<T>

pub fn new(data: T) -> Self

Create a new single-use payload.

pub fn take(&self) -> Option<T>

Takes the value, leaving a None in its place.