How to access callback from imported slint file in rust?

[kkettinger]

I'm trying to separate all properties and callbacks into a extra slint file called "Backend.slint" like this:

export global Backend {
    pure callback set-signal(int);
}

In my App.slint, the import and usage looks like this:

import { Backend } from "Backend.slint";
import { Button } from "std-widgets.slint";

export component App inherits Window {
    Button {
        clicked => {
            Backend.clicked(1);
        }
    }
}

In my main.rs file, i'm trying to access it with ui.global:

fn main() {
	/// ....
	ui.global::<Backend>().on_clicked(|id| {
		println!("On button clicked: id={}", id);
	});
	/// ....
}

But he can't find the Backend scope:

Error[E0412]: cannot find type `Backend` in this scope
  --> src\main.rs:31:21
   |
31 |         ui.global::<Backend>().on_clicked(|id| {
   |                     ^^^^^^^ not found in this scope

When i move the contents of the Backend.slint into the App.slint, it does work:

import { Button } from "std-widgets.slint";

export global Backend {
    pure callback clicked(int);
}

export component App inherits Window {
    Button {
        clicked => {
            Backend.clicked(1);
        }
    }
}

Any idea how to make the Backend scope in a different file public to rust?

[ogoffart]

You can re-export it from the App.slint.

import { Backend } from "Backend.slint";
import { Button } from "std-widgets.slint";

// ADD THIS LINE
export { Backend }

export component App inherits Window {
    Button {
        clicked => {
            Backend.clicked(1);
        }
    }
}

[kkettinger]

Awesome, thank you!