How do I spawn a new window from a callback?

[poperigby]

I have the following code that defines a window with a callback when a button is pressed. I want to catch that callback and spawn a new window when it happens.

import { VerticalBox, HorizontalBox, ComboBox, Button, LineEdit } from "std-widgets.slint";

export component App inherits Window {
    callback open_library_manager();

    title: "Barnacle";

    VerticalBox {
        width: 100%;
        height: 100%;

        // Top bar
        // Global context & high-level management
        HorizontalBox {
            manage-library-button := Button {
                text: @tr("Library");
                clicked => {
                    root.open_library_manager()
                }
            }
        }
    }
}

export component LibraryManager inherits Window {
    title: @tr("Manage Library");
}

Then, from Rust code, I'm catching the callback and trying to spawn the library manager window:

slint::include_modules!();

/// Run the GUI
#[tokio::main]
pub async fn main() {
    let app = App::new().unwrap();
    let library_manager = LibraryManager::new().unwrap();
    let weak_library_manager = library_manager.as_weak();

    app.on_open_library_manager(move || {
        if let Some(lm) = weak_library_manager.upgrade() {
            lm.show().unwrap();
        }
    });

    app.run().unwrap();
}

The problem is, this just doesn't work. The window doesn't show up. What am I doing wrong?

[SergioRibera]

Which version of slint do you have? I have exactly the same thing as you in a project and it works great for me

  let main_window = MainWindow::new().unwrap();
  let view_window = ViewWindow::new().unwrap();

  main_window.on_start_window({
    let view_window = view_window.as_weak();
    move || {
        view_window.unwrap().show().unwrap();
    });

Note

Just keep in mind that globals are not yet shared between window instances #784 (comment), so that part is up to you (an Arc<Mutex<T>> saves me here).

[poperigby]

I'm using 1.14.1. Here's my code in context: https://github.com/poperigby/barnacle/blob/main/barnacle-gui/src/main.rs

When I just do LibraryManager::new().unwrap().show().unwrap(), that shows up fine.

[SergioRibera]

Hey @poperigby , how's it going? I was looking at your project and making a lot of changes trying to get it to work. I'm on Nix, so I was testing changing the flake, updating libs, lots of things, until I tried it on a VM that isn't Nix and it worked perfectly, so my suspicion is that it works on other sites that aren't NixOS, but I couldn't figure out why.

Note

One recommendation: update the slint-build of your dependencies, which you have behind with the slint version.

And try to do this

app.on_open_library_manager({
  let library_manager = library_manager.as_weak();
  move || {
    library_manager.unwrap().show().unwrap();
}});

[poperigby]

OK I updated slint-build and tried your suggestion but it still didn't work. That doesn't make a lot of sense though, does it? Why would just showing the window normally work on NixOS but it doesn't when it's called from a callback?

[poperigby]

Seems like all I have to do to get it to not work is to call show() on LibraryManager after I run() App.

[poperigby]

I'm able to reliably get the button to work here: https://github.com/poperigby/barnacle/blob/main/barnacle-gui/src/main.rs

I had to call show() first, then close the window, then the button works for some reason. I don't want to have to call show() though.