How to share global variables between threads?

[DennisZhangOiler]

Current implementation of global variable uses ModelRc, but I need to update them from different threads. The background is I am writing a multiple livestreams processing APP, it needs to render images captured from livestreams and keep updating them.

[tronical]

ModelRc is neither Send nor Sync at the moment. In the absence of that, the design that I suggest is one where you send the updates through an async-friendly channel and update your model in an local async tasks where model access is safe and easy. Like this pseudo-code:

let (image_sender, image_receiver) = smol::channel::unbounded();

// send `image_sender` to a background thread of yours that feeds images

slint::spawn_local(async move {
    loop {
        if let Ok(image_update) = image_receiver.recv().await {
            let (row, image) = ...
            your_vec_model.set_row_data(row, image); // or append, etc.
        }
    }
})?;

[DennisZhangOiler]

thanks for replying, but the problem is I have to make a button to search all the livestreams, and on its clicked, I add all the images to the GUI then constantly updating the images, I haven't got any good idea to do so.

[tronical]

I'm not sure that I can provide a complete solution here, but perhaps it helps to know that the above pattern can also be reversed: You can have a thread waiting to do things (such as load images) and trigger it by sending messages from the UI thread, using channels. For sending, you don't need to .await.

Also note that the model can be shared between the async task and other closures.