我正在用gtk制作一个小型Web浏览器。这段代码可以正常工作，但我想避免使用所有克隆。

由于闭包的所有权错误，我不能多次使用web_view对象。

extern crate gio;
extern crate gtk;
extern crate webkit2gtk;

use gio::prelude::*;
use gtk::prelude::*;
use gtk::{Application,ApplicationWindow,Button,Entry};
use webkit2gtk::{WebView,WebViewExt};

fn main() {
    let application =
        Application::new(Some("com.github.gtk-rs.examples.basic"),Default::default())
            .expect("failed to initialize GTK application");

    application.connect_activate(|app| {
        let window = ApplicationWindow::new(app);
        window.set_title("Web Browser");
        window.set_default_size(1024,768);

        let button_back = Button::new_with_label("Back");

        let button_next = Button::new_with_label("Next");

        let button_reload = Button::new_with_label("Reload");

        let url_entry = Entry::new();
        url_entry.set_text("https://www.google.com");

        let button_go = Button::new_with_label("Go");

        let web_view = WebView::new();
        web_view.load_uri("https://www.google.com");

        let clone1: WebView = web_view.clone();
        let clone2: WebView = web_view.clone();
        let clone3: WebView = web_view.clone();
        let clone4: WebView = web_view.clone();

        button_back.connect_clicked(move |_| {
            clone1.go_back();
        });

        button_next.connect_clicked(move |_| {
            clone2.go_forward();
        });

        button_reload.connect_clicked(move |_| {
            clone3.reload();
        });

        button_go.connect_clicked(move |_| {
            clone4.load_uri(&url_entry.get_buffer().get_text());
        });
        window.show_all();
    });

    application.run(&[]);
}

这些是我的依赖版本：

[dependencies]
gtk = "0.8.1"
gio = "0.8.1"
webkit2gtk = "0.9.2"

特征connect_clicked的方法gtk::ButtonExt的签名是

fn connect_clicked<F: Fn(&Self) + 'static>(&self,f: F) -> SignalHandlerId