Change CoreWidgets plugin to plugin group. (#20036)

What it says on the tin. :)

crates/bevy_core_widgets/src/lib.rs

@@ -21,7 +21,7 @@ mod core_radio;
 mod core_scrollbar;
 mod core_slider;
 
-use bevy_app::{App, Plugin};
+use bevy_app::{PluginGroup, PluginGroupBuilder};
 
 pub use callback::{Callback, Notify};
 pub use core_button::{CoreButton, CoreButtonPlugin};
@@ -36,18 +36,17 @@ pub use core_slider::{
     SliderRange, SliderStep, SliderValue, TrackClick,
 };
 
-/// A plugin that registers the observers for all of the core widgets. If you don't want to
+/// A plugin group that registers the observers for all of the core widgets. If you don't want to
 /// use all of the widgets, you can import the individual widget plugins instead.
-pub struct CoreWidgetsPlugin;
+pub struct CoreWidgetsPlugins;
 
-impl Plugin for CoreWidgetsPlugin {
-    fn build(&self, app: &mut App) {
-        app.add_plugins((
-            CoreButtonPlugin,
-            CoreCheckboxPlugin,
-            CoreRadioGroupPlugin,
-            CoreScrollbarPlugin,
-            CoreSliderPlugin,
-        ));
+impl PluginGroup for CoreWidgetsPlugins {
+    fn build(self) -> PluginGroupBuilder {
+        PluginGroupBuilder::start::<Self>()
+            .add(CoreButtonPlugin)
+            .add(CoreCheckboxPlugin)
+            .add(CoreRadioGroupPlugin)
+            .add(CoreScrollbarPlugin)
+            .add(CoreSliderPlugin)
     }
 }

examples/ui/core_widgets.rs

@@ -4,7 +4,7 @@ use bevy::{
     color::palettes::basic::*,
     core_widgets::{
         Callback, CoreButton, CoreCheckbox, CoreRadio, CoreRadioGroup, CoreSlider,
-        CoreSliderDragState, CoreSliderThumb, CoreWidgetsPlugin, SliderRange, SliderValue,
+        CoreSliderDragState, CoreSliderThumb, CoreWidgetsPlugins, SliderRange, SliderValue,
         TrackClick,
     },
     input_focus::{
@@ -21,7 +21,7 @@ fn main() {
     App::new()
         .add_plugins((
             DefaultPlugins,
-            CoreWidgetsPlugin,
+            CoreWidgetsPlugins,
             InputDispatchPlugin,
             TabNavigationPlugin,
         ))

examples/ui/core_widgets_observers.rs

@@ -3,7 +3,7 @@
 use bevy::{
     color::palettes::basic::*,
     core_widgets::{
-        Callback, CoreButton, CoreCheckbox, CoreSlider, CoreSliderThumb, CoreWidgetsPlugin,
+        Callback, CoreButton, CoreCheckbox, CoreSlider, CoreSliderThumb, CoreWidgetsPlugins,
         SliderRange, SliderValue,
     },
     ecs::system::SystemId,
@@ -21,7 +21,7 @@ fn main() {
     App::new()
         .add_plugins((
             DefaultPlugins,
-            CoreWidgetsPlugin,
+            CoreWidgetsPlugins,
             InputDispatchPlugin,
             TabNavigationPlugin,
         ))

examples/ui/feathers.rs

@@ -1,7 +1,7 @@
 //! This example shows off the various Bevy Feathers widgets.
 
 use bevy::{
-    core_widgets::{Callback, CoreRadio, CoreRadioGroup, CoreWidgetsPlugin, SliderStep},
+    core_widgets::{Callback, CoreRadio, CoreRadioGroup, CoreWidgetsPlugins, SliderStep},
     feathers::{
         controls::{
             button, checkbox, radio, slider, toggle_switch, ButtonProps, ButtonVariant,
@@ -25,7 +25,7 @@ fn main() {
     App::new()
         .add_plugins((
             DefaultPlugins,
-            CoreWidgetsPlugin,
+            CoreWidgetsPlugins,
             InputDispatchPlugin,
             TabNavigationPlugin,
             FeathersPlugin,

release-content/release-notes/headless-widgets.md

@@ -1,7 +1,7 @@
 ---
 title: Headless Widgets
 authors: ["@viridia", "@ickshonpe", "@alice-i-cecile"]
-pull_requests: [19366, 19584, 19665, 19778, 19803]
+pull_requests: [19366, 19584, 19665, 19778, 19803, 20036]
 ---
 
 Bevy's `Button` and `Interaction` components have been around for a long time. Unfortunately