main.rs

use std::cell::Ref;
use gtk::{Application, gio};
use gtk::glib::BoxedAnyObject;
use gtk::prelude::*;

// Cargo.toml's dependencies:
// gtk = { version = "0.4.8", package = "gtk4" }

fn main() {
    let application = Application::builder()
        .application_id("org.gnome.test")
        .build();

    application.connect_activate(build_ui);

    application.run();
}

struct Entry(&'static str, usize);

fn build_ui(app: &Application) {
    let model = gio::ListStore::new(BoxedAnyObject::static_type());

    let v = vec![
        BoxedAnyObject::new(Entry("Row 1", 10)),
        BoxedAnyObject::new(Entry("Row 2", 20)),
        BoxedAnyObject::new(Entry("Row 3", 35)),
        BoxedAnyObject::new(Entry("Row 4", 49)),
    ];
    model.extend_from_slice(&v);

    let model = gtk::SingleSelection::new(Some(&model));
    let columnview = gtk::ColumnView::builder()
        .model(&model)
        .vexpand(true)
        .hexpand(true)
        .margin_bottom(12)
        .margin_end(12)
        .margin_start(12)
        .margin_top(12)
        .show_column_separators(true)
        .build();

    {
        let factory = gtk::SignalListItemFactory::new();
        factory.connect_setup(move |_, li| {
            let label = gtk::Label::new(None);
            li.set_child(Some(&label));
        });
        factory.connect_bind(move |_, li| {
            let obj = li.item().unwrap().downcast::<BoxedAnyObject>().unwrap();
            let entry: Ref<Entry> = obj.borrow();
            let label = li.child().unwrap().downcast::<gtk::Label>().unwrap();
            label.set_label(entry.0);
        });
        let col = gtk::ColumnViewColumn::new(Some("Title"), Some(&factory));
        col.set_expand(true);
        columnview.append_column(&col);
    }

    {
        let factory = gtk::SignalListItemFactory::new();
        factory.connect_setup(move |_, li| {
            let label = gtk::Label::new(None);
            li.set_child(Some(&label));
        });
        factory.connect_bind(move |_, li| {
            let obj = li.item().unwrap().downcast::<BoxedAnyObject>().unwrap();
            let entry: Ref<Entry> = obj.borrow();
            let label = li.child().unwrap().downcast::<gtk::Label>().unwrap();
            label.set_label(format!("{}", entry.1).as_str());
        });
        let col = gtk::ColumnViewColumn::new(Some("Number"), Some(&factory));
        columnview.append_column(&col);
    }

    let window = gtk::ApplicationWindow::builder()
        .application(app)
        .child(&columnview)
        .build();

    window.show();
}