fix adwaita-demo folder

adwaita-demo/src/main.rs

@@ -0,0 +1,58 @@
+use adw::prelude::*;
+use gtk::prelude::*;
+
+use adw::{ActionRow, ApplicationWindow, HeaderBar};
+use gtk::{Application, Box, ListBox, Orientation};
+
+fn main() {
+    let application = Application::builder()
+        .application_id("com.example.FirstAdwaitaApp")
+        .build();
+
+    application.connect_startup(|_| {
+        adw::init();
+    });
+
+    application.connect_activate(|app| {
+        // ActionRows are only available in Adwaita
+        let row = ActionRow::builder()
+            .activatable(true)
+            .selectable(false)
+            .title("Click me")
+            .build();
+        row.connect_activated(|x| {
+            eprintln!("Clicked! {:?}", x);
+        });
+
+        
+        let list = ListBox::builder()
+            .margin_top(32)
+            .margin_end(32)
+            .margin_bottom(32)
+            .margin_start(32)
+            // the content class makes the list look nicer
+            .css_classes(vec![String::from("content")])
+            .build();
+        list.append(&row);
+
+        // Combine the content in a box
+        let content = Box::new(Orientation::Vertical, 0);
+        // Adwaitas' ApplicationWindow does not include a HeaderBar
+        content.append(
+            &HeaderBar::builder()
+                .title_widget(&adw::WindowTitle::new("First App", ""))
+                .build(),
+        );
+        content.append(&list);
+
+        let window = ApplicationWindow::builder()
+            .application(app)
+            .default_width(350)
+            // add content to window
+            .content(&content)
+            .build();
+        window.show();
+    });
+
+    application.run();
+}