Add an example of using a RadioSet.Changed message

docs/examples/widgets/radio_set_changed.css

@@ -0,0 +1,12 @@
+Vertical {
+    align: center middle;
+}
+
+Horizontal {
+    align: center middle;
+    height: auto;
+}
+
+RadioSet {
+    width: 45%;
+}

docs/examples/widgets/radio_set_changed.py

@@ -0,0 +1,43 @@
+from textual.app import App, ComposeResult
+from textual.containers import Horizontal, Vertical
+from textual.widgets import Label, RadioButton, RadioSet
+
+
+class RadioSetChangedApp(App[None]):
+    CSS_PATH = "radio_set_changed.css"
+
+    def compose(self) -> ComposeResult:
+        with Vertical():
+            with Horizontal():
+                with RadioSet():
+                    yield RadioButton("Battlestar Galactica")
+                    yield RadioButton("Dune 1984")
+                    yield RadioButton("Dune 2021")
+                    yield RadioButton("Serenity", value=True)
+                    yield RadioButton("Star Trek: The Motion Picture")
+                    yield RadioButton("Star Wars: A New Hope")
+                    yield RadioButton("The Last Starfighter")
+                    yield RadioButton(
+                        "Total Recall :backhand_index_pointing_right: :red_circle:",
+                        id="focus_me",
+                    )
+                    yield RadioButton("Wing Commander")
+            with Horizontal():
+                yield Label(id="pressed")
+            with Horizontal():
+                yield Label(id="index")
+
+    def on_mount(self) -> None:
+        self.query_one("#focus_me", RadioButton).focus()
+
+    def on_radio_set_changed(self, event: RadioSet.Changed) -> None:
+        self.query_one("#pressed", Label).update(
+            f"Pressed button label: {event.pressed.label}"
+        )
+        self.query_one("#index", Label).update(
+            f"Pressed button index: {event.input.pressed_index}"
+        )
+
+
+if __name__ == "__main__":
+    RadioSetChangedApp().run()

docs/widgets/radioset.md

@@ -31,6 +31,25 @@ The example below shows two radio sets, one built using a collection of
 
 ### ::: textual.widgets.RadioSet.Changed
 
+Here is an example of using the message to react to changes in a `RadioSet`:
+
+=== "Output"
+
+    ```{.textual path="docs/examples/widgets/radio_set_changed.py" press="enter"}
+    ```
+
+=== "radio_set_changed.py"
+
+    ```python
+    --8<-- "docs/examples/widgets/radio_set_changed.py"
+    ```
+
+=== "radio_set_changed.css"
+
+    ```sass
+    --8<-- "docs/examples/widgets/radio_set_changed.css"
+    ```
+
 ## See Also
 
 - [RadioSet](../api/radioset.md) code reference