How can I use async function in slint-ui

[Decodetalkers]

I haven't found async key word in the example. How can I use it ?

[tronical]

You’re right, none of our examples use async (yet). However you can look into the cargo-ui source code to find an approach of combining Slint with async: https://github.com/slint-ui/cargo-ui

[ogoffart]

Right, we should have a convinient way to run async code.
But we actually do use future in our viewer and LSP implementation

slint/tools/viewer/main.rs

Lines 342 to 369 in 474eb34

	struct FutureRunner {
	fut: Mutex<Option<Pin<Box<dyn Future<Output = ()>>>>>,
	}
	/// Safety: the future is only going to be run in the UI thread
	unsafe impl Send for FutureRunner {}
	/// Safety: the future is only going to be run in the UI thread
	unsafe impl Sync for FutureRunner {}
	impl Wake for FutureRunner {
	fn wake(self: Arc<Self>) {
	i_slint_backend_selector::backend().post_event(Box::new(move || {
	let waker = self.clone().into();
	let mut cx = std::task::Context::from_waker(&waker);
	let mut fut_opt = self.fut.lock().unwrap();
	if let Some(fut) = &mut *fut_opt {
	match fut.as_mut().poll(&mut cx) {
	std::task::Poll::Ready(_) => *fut_opt = None,
	std::task::Poll::Pending => {}
	}
	}
	}));
	}
	}
	fn run_in_ui_thread(fut: Pin<Box<dyn Future<Output = ()>>>) {
	Arc::new(FutureRunner { fut: Mutex::new(Some(fut)) }).wake()
	}

Unfortunately, you can't use it as is as it uses private API, but you can replace the i_slint_backend_selector::backend().post_event with slint::invoke_from_event_loop and that should get you a way to run futures in the slint event loop.