rust - Gtk-ERROR **: UI の追加に失敗しました: 行 1 文字 1 でエラーが発生しました: ドキュメントは要素で開始する必要があります

Question

GTK+ 3 がこのエラーをスローするのはなぜですか?

(.:11977): Gtk-ERROR **: 21:10:01.149: failed to add UI: Errore alla riga 1 carattere 1: Il documento deve iniziare con un elemento (es. <book>)

イタリア語から英語への翻訳:

(.:11977): Gtk-ERROR **: 21:10:01.149: failed to add UI: Error on line 1 char 1: Document must begin with an element (e.g. <book>)

このエラーは、Rust が空のファイル (Glade で作成された) を開こうとしているか、構文が間違っていることを示しています。

私のRustファイルはエラーなしでコンパイルされます:

extern crate gtk;

use gtk::traits::*;
use gtk::Builder;
use gtk::Inhibit;

fn main() {
    // Initialise gtk components
    if gtk::init().is_err() {
        println!("Unable to load GTK.");
        return;
    }

    // Load glade file
    let builder = Builder::new_from_string("mainWindow.glade");

    // Create Window
    let window: gtk::Window = builder.get_object("mainWindow").unwrap();

    // Set close event
    window.connect_delete_event(|_, _| {
        gtk::main_quit();
        Inhibit(true)
    });

    // Show the window and call the main() loop of gtk
    window.show_all();
    gtk::main();
}

(錆びファイル)

Glade ファイルは次のとおりです。

<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.22.1 -->
<interface>
    <requires lib="gtk+" version="3.20"/>
    <!-- interface-css-provider-path style.css -->
    <object class="GtkWindow" id="mainWindow">
        <property name="can_focus">False</property>
        <property name="window_position">center</property>
        <property name="default_width">500</property>
        <property name="default_height">350</property>
        <child type="titlebar">
            <object class="GtkHeaderBar">
                <property name="visible">True</property>
                <property name="can_focus">False</property>
                <property name="title" translatable="yes">rustup-gui</property>
                <property name="subtitle" translatable="yes">A simple GUI for rustup.</property>
                <property name="show_close_button">True</property>
                <child>
                    <object class="GtkMenuBar">
                        <property name="visible">True</property>
                        <property name="can_focus">False</property>
                        <child>
                            <object class="GtkMenuItem">
                                <property name="visible">True</property>
                                <property name="can_focus">False</property>
                                <property name="tooltip_text" translatable="yes">Here you can find some basic action which can be done with rustup.</property>
                                <property name="label" translatable="yes">Rustup</property>
                                <property name="use_underline">True</property>
                                <child type="submenu">
                                    <object class="GtkMenu">
                                        <property name="visible">True</property>
                                        <property name="can_focus">False</property>
                                        <child>
                                            <object class="GtkMenuItem">
                                                <property name="visible">True</property>
                                                <property name="can_focus">False</property>
                                                <property name="tooltip_text" translatable="yes">Get all the info related to the current rustup installation.</property>
                                                <property name="label" translatable="yes">Info</property>
                                                <property name="use_underline">True</property>
                                            </object>
                                        </child>
                                    </object>
                                </child>
                            </object>
                        </child>
                        <child>
                            <object class="GtkMenuItem">
                                <property name="visible">True</property>
                                <property name="can_focus">False</property>
                                <property name="label" translatable="yes">Set...</property>
                                <property name="use_underline">True</property>
                                <child type="submenu">
                                    <object class="GtkMenu">
                                        <property name="visible">True</property>
                                        <property name="can_focus">False</property>
                                        <child>
                                            <object class="GtkMenuItem">
                                                <property name="visible">True</property>
                                                <property name="can_focus">False</property>
                                                <property name="label" translatable="yes">Default toolchain</property>
                                                <property name="use_underline">True</property>
                                            </object>
                                        </child>
                                    </object>
                                </child>
                            </object>
                        </child>
                    </object>
                </child>
            </object>
        </child>
        <child>
            <object class="GtkBox">
                <property name="visible">True</property>
                <property name="can_focus">False</property>
                <property name="orientation">vertical</property>
                <child>
                    <object class="GtkBox">
                        <property name="visible">True</property>
                        <property name="can_focus">False</property>
                        <child>
                            <object class="GtkCheckButton">
                                <property name="label" translatable="yes">Vervose output (-v)</property>
                                <property name="visible">True</property>
                                <property name="can_focus">True</property>
                                <property name="receives_default">False</property>
                                <property name="draw_indicator">True</property>
                                <signal name="toggled" handler="tglVerbose_Toggled" swapped="no"/>
                            </object>
                            <packing>
                                <property name="expand">False</property>
                                <property name="fill">True</property>
                                <property name="position">0</property>
                            </packing>
                        </child>
                        <child>
                            <object class="GtkLabel">
                                <property name="visible">True</property>
                                <property name="can_focus">False</property>
                                <property name="margin_left">5</property>
                                <property name="margin_right">5</property>
                                <property name="margin_top">5</property>
                                <property name="margin_bottom">5</property>
                                <property name="label" translatable="yes">Custom command</property>
                            </object>
                            <packing>
                                <property name="expand">False</property>
                                <property name="fill">True</property>
                                <property name="position">1</property>
                            </packing>
                        </child>
                        <child>
                            <object class="GtkEntry">
                                <property name="visible">True</property>
                                <property name="can_focus">True</property>
                                <property name="margin_left">5</property>
                                <property name="margin_right">5</property>
                                <property name="margin_top">5</property>
                                <property name="margin_bottom">5</property>
                                <property name="placeholder_text" translatable="yes">rustup ...</property>
                            </object>
                            <packing>
                                <property name="expand">True</property>
                                <property name="fill">True</property>
                                <property name="position">2</property>
                            </packing>
                        </child>
                    </object>
                    <packing>
                        <property name="expand">False</property>
                        <property name="fill">True</property>
                        <property name="position">0</property>
                    </packing>
                </child>
                <child>
                    <object class="GtkFrame">
                        <property name="visible">True</property>
                        <property name="can_focus">False</property>
                        <property name="margin_left">5</property>
                        <property name="margin_right">5</property>
                        <property name="margin_top">5</property>
                        <property name="margin_bottom">5</property>
                        <property name="label_xalign">0.5</property>
                        <property name="shadow_type">in</property>
                        <child>
                            <object class="GtkAlignment">
                                <property name="visible">True</property>
                                <property name="can_focus">False</property>
                                <child>
                                    <object class="GtkTextView" id="txtOutput">
                                        <property name="width_request">100</property>
                                        <property name="height_request">130</property>
                                        <property name="visible">True</property>
                                        <property name="can_focus">True</property>
                                        <property name="margin_left">5</property>
                                        <property name="margin_right">5</property>
                                        <property name="margin_top">5</property>
                                        <property name="margin_bottom">5</property>
                                        <property name="hexpand">True</property>
                                        <property name="vexpand">True</property>
                                        <property name="editable">False</property>
                                        <property name="monospace">True</property>
                                    </object>
                                </child>
                            </object>
                        </child>
                        <child type="label">
                            <object class="GtkLabel">
                                <property name="visible">True</property>
                                <property name="can_focus">False</property>
                                <property name="label" translatable="yes">Console output</property>
                            </object>
                        </child>
                    </object>
                    <packing>
                        <property name="expand">True</property>
                        <property name="fill">True</property>
                        <property name="position">1</property>
                    </packing>
                </child>
            </object>
        </child>
    </object>
</interface>

(グレードファイル)

このエラーを検索しようとしましたが、私以外にこの厄介なエラーを経験した人はいないようです。多分それは私のOSに関連していますか？System76 製の Ubuntu ベースの Linux ディストリビューションである Pop!_OS を使用しています。