feat: Add ability to add/remove multiple overlays at once (flame-engi…

…ne#1657)

As described flame-engine#1546, It would be more convenient and can reduce the game widget updates if adding or removing overlays at once.

packages/flame/lib/src/game/game_widget/game_widget.dart

@@ -116,7 +116,7 @@ class GameWidget<T extends Game> extends StatefulWidget {
       game.mouseCursor = mouseCursor;
     }
     if (initialActiveOverlays != null) {
-      initialActiveOverlays.forEach(game.overlays.add);
+      game.overlays.addAll(initialActiveOverlays);
     }
   }
 

packages/flame/lib/src/game/mixins/game.dart

@@ -325,6 +325,17 @@ class _ActiveOverlays {
     return setChanged;
   }
 
+  /// Marks [overlayNames] to be rendered.
+  void addAll(Iterable<String> overlayNames) {
+    final overlayCountBeforeAdded = _activeOverlays.length;
+    _activeOverlays.addAll(overlayNames);
+
+    final overlayCountAfterAdded = _activeOverlays.length;
+    if (overlayCountBeforeAdded != overlayCountAfterAdded) {
+      _game?._refreshWidget();
+    }
+  }
+
   /// Hides the [overlayName].
   bool remove(String overlayName) {
     final hasRemoved = _activeOverlays.remove(overlayName);
@@ -334,6 +345,17 @@ class _ActiveOverlays {
     return hasRemoved;
   }
 
+  /// Hides multiple overlays specified in [overlayNames].
+  void removeAll(Iterable<String> overlayNames) {
+    final overlayCountBeforeRemoved = _activeOverlays.length;
+    _activeOverlays.removeAll(overlayNames);
+
+    final overlayCountAfterRemoved = _activeOverlays.length;
+    if (overlayCountBeforeRemoved != overlayCountAfterRemoved) {
+      _game?._refreshWidget();
+    }
+  }
+
   /// The names of all currently active overlays.
   Set<String> get value => _activeOverlays;
 

packages/flame/test/game/active_overlays_test.dart

@@ -19,6 +19,27 @@ void main() {
       });
     });
 
+    group('addAll', () {
+      test('can add multiple overlays at once', () {
+        final overlays = FlameGame().overlays;
+        overlays.addAll(['test', 'test2']);
+        expect(overlays.isActive('test'), true);
+        expect(overlays.isActive('test2'), true);
+      });
+    });
+
+    group('removeAll', () {
+      test('can remove multiple overlays at once', () {
+        final overlays = FlameGame().overlays;
+        overlays.addAll(['test', 'test2']);
+
+        overlays.removeAll(['test', 'test2']);
+
+        expect(overlays.isActive('test'), false);
+        expect(overlays.isActive('test2'), false);
+      });
+    });
+
     group('remove', () {
       test('can remove an overlay', () {
         final overlays = FlameGame().overlays;