Share UI between screens

The recording screen was reverted to a dummy in the process.

src/widgets/section.rs

@@ -0,0 +1,48 @@
+use gtk::prelude::*;
+use gtk_macros::get_widget;
+
+/// A widget displaying a title, a framed child widget and, if needed, some
+/// actions.
+pub struct Section {
+    /// The actual GTK widget.
+    pub widget: gtk::Box,
+
+    /// The box containing the title and action buttons.
+    title_box: gtk::Box,
+}
+
+impl Section {
+    /// Create a new section.
+    pub fn new<W: IsA<gtk::Widget>>(title: &str, content: &W) -> Self {
+        let builder = gtk::Builder::from_resource("/de/johrpan/musicus/ui/section.ui");
+
+        get_widget!(builder, gtk::Box, widget);
+        get_widget!(builder, gtk::Box, title_box);
+        get_widget!(builder, gtk::Label, title_label);
+        get_widget!(builder, gtk::Frame, frame);
+
+        title_label.set_label(title);
+        frame.set_child(Some(content));
+
+        Self {
+            widget,
+            title_box,
+        }
+    }
+
+    /// Add an action button. This should by definition be something that is
+    /// doing something with the child widget that is applicable in all
+    /// situations where the widget is visible. The new button will be packed
+    /// to the end of the title box.
+    pub fn add_action<F: Fn() + 'static>(&self, icon_name: &str, cb: F) {
+        let button = gtk::ButtonBuilder::new()
+            .has_frame(false)
+            .valign(gtk::Align::Center)
+            .icon_name(icon_name)
+            .build();
+
+        button.connect_clicked(move |_| cb());
+
+        self.title_box.append(&button);
+    }
+}