[google_maps_flutter] Add MapColorScheme support to Android and iOS

Wires MapColorScheme (light/dark/followSystem) through to the native
APIs on Android and iOS. The platform interface and app-facing package
already exposed colorScheme (added in 2.16.0 for web), but the Android
and iOS implementations ignored it.

* Android: calls GoogleMap.setMapColorScheme() with the matching
  MapColorScheme constant, both at creation and on runtime configuration
  updates.
* iOS: sets GMSMapView.overrideUserInterfaceStyle to light/dark/
  unspecified, the documented Google Maps SDK for iOS approach.

The iOS change is mirrored across google_maps_flutter_ios,
google_maps_flutter_ios_sdk9, google_maps_flutter_ios_sdk10, and
google_maps_flutter_ios_shared_code via tool/sync_shared_files.dart. The
colorScheme doc comments in google_maps_flutter and
google_maps_flutter_platform_interface are updated to reflect the new
platform support.

Adds Convert and dispatcher tests plus Dart creation-params tests on
Android, parametrized creation-params tests on iOS, and a native
FGMGoogleMapController test exercising the runtime color scheme update.

Fixes flutter/flutter#186737

Author: snaeji

packages/google_maps_flutter/google_maps_flutter/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.17.2
+
+* Updates `colorScheme` doc comment to reflect Android and iOS support.
+
 ## 2.17.1
 
 * Updates README to link to implementation packages for platform-specific

packages/google_maps_flutter/google_maps_flutter/lib/src/google_map.dart

@@ -402,10 +402,15 @@ class GoogleMap extends StatefulWidget {
   /// may result in unexpected behavior.
   final GoogleMapMarkerType markerType;
 
-  /// Color scheme for the cloud-style map. Web only.
+  /// Color scheme for the map.
   ///
-  /// The colorScheme option can only be set when the map is initialized;
-  /// setting this option after the map is created will have no effect.
+  /// On Android and iOS, the color scheme can be updated after the map is
+  /// created. On web, the value is applied only at map creation; later
+  /// changes have no effect.
+  ///
+  /// The map must use a cloud-based map style (via [mapId]) for the
+  /// color scheme to affect the base map tiles; otherwise the effect is
+  /// limited to map UI chrome.
   ///
   /// See https://developers.google.com/maps/documentation/javascript/mapcolorscheme for more details.
   final MapColorScheme? colorScheme;

packages/google_maps_flutter/google_maps_flutter/pubspec.yaml

@@ -2,7 +2,7 @@ name: google_maps_flutter
 description: A Flutter plugin for integrating Google Maps in iOS and Android applications.
 repository: https://github.com/flutter/packages/tree/main/packages/google_maps_flutter/google_maps_flutter
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+maps%22
-version: 2.17.1
+version: 2.17.2
 
 environment:
   sdk: ^3.10.0

packages/google_maps_flutter/google_maps_flutter_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.20.0
+
+* Adds `colorScheme` support for cloud-based maps styling brightness.
+
 ## 2.19.12
 
 * Bumps the androidx group across 10 directories with 1 update.

packages/google_maps_flutter/google_maps_flutter_android/android/src/main/java/io/flutter/plugins/googlemaps/Convert.java

@@ -577,6 +577,18 @@ static void interpretMapConfiguration(
     if (style != null) {
       sink.setMapStyle(style);
     }
+    final PlatformMapColorScheme colorScheme = config.getColorScheme();
+    if (colorScheme != null) {
+      sink.setMapColorScheme(toMapColorScheme(colorScheme));
+    }
+  }
+
+  static int toMapColorScheme(@NonNull PlatformMapColorScheme colorScheme) {
+    return switch (colorScheme) {
+      case LIGHT -> com.google.android.gms.maps.model.MapColorScheme.LIGHT;
+      case DARK -> com.google.android.gms.maps.model.MapColorScheme.DARK;
+      case FOLLOW_SYSTEM -> com.google.android.gms.maps.model.MapColorScheme.FOLLOW_SYSTEM;
+    };
   }
 
   /** Set the options in the given object to marker options sink. */

packages/google_maps_flutter/google_maps_flutter_android/android/src/main/java/io/flutter/plugins/googlemaps/GoogleMapBuilder.java

@@ -32,6 +32,7 @@ class GoogleMapBuilder implements GoogleMapOptionsSink {
   private List<PlatformGroundOverlay> initialGroundOverlays;
   private Rect padding = new Rect(0, 0, 0, 0);
   private @Nullable String style;
+  private @Nullable Integer mapColorScheme;
 
   GoogleMapController build(
       int id,
@@ -59,6 +60,7 @@ GoogleMapController build(
     controller.setInitialTileOverlays(initialTileOverlays);
     controller.setInitialGroundOverlays(initialGroundOverlays);
     controller.setMapStyle(style);
+    controller.setMapColorScheme(mapColorScheme);
     return controller;
   }
 
@@ -209,4 +211,9 @@ public void setInitialGroundOverlays(@NonNull List<PlatformGroundOverlay> initia
   public void setMapStyle(@Nullable String style) {
     this.style = style;
   }
+
+  @Override
+  public void setMapColorScheme(@Nullable Integer colorScheme) {
+    this.mapColorScheme = colorScheme;
+  }
 }

packages/google_maps_flutter/google_maps_flutter_android/android/src/main/java/io/flutter/plugins/googlemaps/GoogleMapController.java

@@ -111,6 +111,8 @@ class GoogleMapController
   private @Nullable List<PlatformGroundOverlay> initialGroundOverlays;
   // Null except between initialization and onMapReady.
   private @Nullable String initialMapStyle;
+  // Null except between initialization and onMapReady.
+  private @Nullable Integer initialMapColorScheme;
   private boolean lastSetStyleSucceeded;
   @VisibleForTesting List<Float> initialPadding;
 
@@ -245,6 +247,10 @@ public void onMapReady(@NonNull GoogleMap googleMap) {
       updateMapStyle(initialMapStyle);
       initialMapStyle = null;
     }
+    if (initialMapColorScheme != null) {
+      googleMap.setMapColorScheme(initialMapColorScheme);
+      initialMapColorScheme = null;
+    }
   }
 
   // Returns the first TextureView found in the view hierarchy.
@@ -853,6 +859,17 @@ public void setMapStyle(@Nullable String style) {
     }
   }
 
+  public void setMapColorScheme(@Nullable Integer colorScheme) {
+    if (colorScheme == null) {
+      return;
+    }
+    if (googleMap == null) {
+      initialMapColorScheme = colorScheme;
+    } else {
+      googleMap.setMapColorScheme(colorScheme);
+    }
+  }
+
   private boolean updateMapStyle(String style) {
     // Dart passes an empty string to indicate that the style should be cleared.
     final MapStyleOptions mapStyleOptions =

packages/google_maps_flutter/google_maps_flutter_android/android/src/main/java/io/flutter/plugins/googlemaps/GoogleMapOptionsSink.java

@@ -64,4 +64,6 @@ interface GoogleMapOptionsSink {
   void setInitialGroundOverlays(@NonNull List<PlatformGroundOverlay> initialGroundOverlays);
 
   void setMapStyle(@Nullable String style);
+
+  void setMapColorScheme(@Nullable Integer colorScheme);
 }