AppWindow

// AppCenter MainWindow.vala

public class AppCenter.MainWindow : Gtk.ApplicationWindow {
    /* some code here */

    /* ... */
    installed_view.subview_entered.connect (view_opened);
    search_view.subview_entered.connect (view_opened);

    if (is_connection_available()) {
        stack.set_visible_child (category_view);
    } else {
        stack.set_visible_child (network_grid_view);
    }
}

private bool is_connection_available () {
    if (NetworkMonitor.get_default ().get_network_available () || NetworkMonitor.get_default ().get_network_metered ()) {
        return true;
    }

    return false;
}