[google_map_flutter] Add style to widget - platform interface (#6197)

Platform interface portion of #6192

Adds `style` to `MapConfiguration` and adds new `getStyleError` method.

Part of Fixes flutter/flutter#66207

Author: stuartmorgan-g

packages/google_maps_flutter/google_maps_flutter_platform_interface/CHANGELOG.md

@@ -1,5 +1,9 @@
-## NEXT
+## 2.5.0
 
+* Adds `style` to the `MapConfiguration` to allow setting style as part of
+  map creation.
+* Adds `getStyleError` to the platform interface, to allow asynchronous access
+  to style errors that occur during initialization.
 * Updates minimum supported SDK version to Flutter 3.13/Dart 3.1.
 
 ## 2.4.3

packages/google_maps_flutter/google_maps_flutter_platform_interface/lib/src/platform_interface/google_maps_flutter_platform.dart

@@ -362,6 +362,12 @@ abstract class GoogleMapsFlutterPlatform extends PlatformInterface {
     throw UnimplementedError('dispose() has not been implemented.');
   }
 
+  /// If the last attempt to set the style via [MapConfiguration.style] failed,
+  /// returns the error information, otherwise returns null.
+  Future<String?> getStyleError({required int mapId}) async {
+    return null;
+  }
+
   /// Returns a widget displaying the map view - deprecated, use
   /// [buildViewWithConfiguration] instead.
   Widget buildView(

packages/google_maps_flutter/google_maps_flutter_platform_interface/lib/src/types/map_configuration.dart

@@ -36,6 +36,7 @@ class MapConfiguration {
     this.trafficEnabled,
     this.buildingsEnabled,
     this.cloudMapId,
+    this.style,
   });
 
   /// This setting controls how the API handles gestures on the map. Web only.
@@ -113,6 +114,11 @@ class MapConfiguration {
   /// for more details.
   final String? cloudMapId;
 
+  /// Locally configured JSON style.
+  ///
+  /// To clear a previously set style, set this to an empty string.
+  final String? style;
+
   /// Returns a new options object containing only the values of this instance
   /// that are different from [other].
   MapConfiguration diffFrom(MapConfiguration other) {
@@ -174,6 +180,7 @@ class MapConfiguration {
       buildingsEnabled:
           buildingsEnabled != other.buildingsEnabled ? buildingsEnabled : null,
       cloudMapId: cloudMapId != other.cloudMapId ? cloudMapId : null,
+      style: style != other.style ? style : null,
     );
   }
 
@@ -206,6 +213,7 @@ class MapConfiguration {
       trafficEnabled: diff.trafficEnabled ?? trafficEnabled,
       buildingsEnabled: diff.buildingsEnabled ?? buildingsEnabled,
       cloudMapId: diff.cloudMapId ?? cloudMapId,
+      style: diff.style ?? style,
     );
   }
 
@@ -231,7 +239,8 @@ class MapConfiguration {
       indoorViewEnabled == null &&
       trafficEnabled == null &&
       buildingsEnabled == null &&
-      cloudMapId == null;
+      cloudMapId == null &&
+      style == null;
 
   @override
   bool operator ==(Object other) {
@@ -262,7 +271,8 @@ class MapConfiguration {
         indoorViewEnabled == other.indoorViewEnabled &&
         trafficEnabled == other.trafficEnabled &&
         buildingsEnabled == other.buildingsEnabled &&
-        cloudMapId == other.cloudMapId;
+        cloudMapId == other.cloudMapId &&
+        style == other.style;
   }
 
   @override
@@ -288,5 +298,6 @@ class MapConfiguration {
         trafficEnabled,
         buildingsEnabled,
         cloudMapId,
+        style,
       ]);
 }

packages/google_maps_flutter/google_maps_flutter_platform_interface/lib/src/types/utils/map_configuration_serialization.dart

@@ -59,5 +59,6 @@ Map<String, Object> jsonForMapConfiguration(MapConfiguration config) {
     if (config.buildingsEnabled != null)
       'buildingsEnabled': config.buildingsEnabled!,
     if (config.cloudMapId != null) 'cloudMapId': config.cloudMapId!,
+    if (config.style != null) 'style': config.style!,
   };
 }

packages/google_maps_flutter/google_maps_flutter_platform_interface/pubspec.yaml

@@ -4,7 +4,7 @@ repository: https://github.com/flutter/packages/tree/main/packages/google_maps_f
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+maps%22
 # NOTE: We strongly prefer non-breaking changes, even at the expense of a
 # less-clean API. See https://flutter.dev/go/platform-interface-breaking-changes
-version: 2.4.3
+version: 2.5.0
 
 environment:
   sdk: ^3.1.0

packages/google_maps_flutter/google_maps_flutter_platform_interface/test/platform_interface/google_maps_flutter_platform_test.dart

@@ -83,6 +83,15 @@ void main() {
         );
       },
     );
+
+    test(
+      'default implementation of `getStyleError` returns null',
+      () async {
+        final GoogleMapsFlutterPlatform platform =
+            BuildViewGoogleMapsFlutterPlatform();
+        expect(await platform.getStyleError(mapId: 0), null);
+      },
+    );
   });
 }
 

packages/google_maps_flutter/google_maps_flutter_platform_interface/test/types/map_configuration_test.dart

@@ -33,6 +33,7 @@ void main() {
       indoorViewEnabled: false,
       trafficEnabled: false,
       buildingsEnabled: false,
+      style: 'diff base style',
     );
 
     test('only include changed fields', () async {
@@ -408,6 +409,23 @@ void main() {
       // The hash code should change.
       expect(empty.hashCode, isNot(diff.hashCode));
     });
+
+    test('handle style', () async {
+      const String aStlye = 'a style';
+      const MapConfiguration diff = MapConfiguration(style: aStlye);
+
+      const MapConfiguration empty = MapConfiguration();
+      final MapConfiguration updated = diffBase.applyDiff(diff);
+
+      // A diff applied to empty options should be the diff itself.
+      expect(empty.applyDiff(diff), diff);
+      // The diff from empty options should be the diff itself.
+      expect(diff.diffFrom(empty), diff);
+      // A diff applied to non-empty options should update that field.
+      expect(updated.style, aStlye);
+      // The hash code should change.
+      expect(empty.hashCode, isNot(diff.hashCode));
+    });
   });
 
   group('isEmpty', () {
@@ -541,5 +559,11 @@ void main() {
 
       expect(diff.isEmpty, false);
     });
+
+    test('is false with style', () async {
+      const MapConfiguration diff = MapConfiguration(style: 'a style');
+
+      expect(diff.isEmpty, false);
+    });
   });
 }