How to force a widget to read the updated value in gtk-rs?

[gtkinrust (Alex K)]

Hello, I am trying to get a label that holds a reference to a value in Rc<Cell(i32)> that is updated via a button ‘button_inc’. Although the value is increased in the println! the label is not updated. What am I doing wrong?

Thank you in advance for helping, Alex

use gtk::glib;
use gtk::prelude::*;
use gtk::Application;
use std::cell::Cell;
use std::rc::Rc;

static APP_ID: &str = "org.gtkrs-experiment";

fn main() -> glib::ExitCode {
    let app = gtk::Application::builder().application_id(APP_ID).build();
    app.connect_activate(build_ui);
    app.run()
}

fn build_ui(application: &Application) {
    let number = Rc::new(Cell::new(0));

    let number_inc = number.clone();
    let button_inc = gtk::Button::builder().label("Plus 1").build();

    button_inc.connect_clicked(move |_| {
        number_inc.set(number_inc.get() + 1);
        println!("The number_inc: {}", number_inc.get());
    });

    let label_info = gtk::Label::builder()
        .label(format!("The number is {}", number.get()))
        .build();

    let vbox = gtk::Box::builder()
        .orientation(gtk::Orientation::Vertical)
        .build();

    vbox.append(&label_info);
    vbox.append(&button_inc);

    let window = gtk::ApplicationWindow::builder()
        .application(application)
        .title("GTK Counter Experiment")
        .child(&vbox)
        .build();

    window.present()
}

[jfrancis (Jason Francis)]

Hello, by default gtk widgets do not have any data binding. So you would have to also clone the label into the clicked callback and then do label_info.set_text("..."); to change the text every time.