[google_maps_flutter(_platform_interface)] Make the plugin friendlier to the web implementation.

packages/google_maps_flutter/google_maps_flutter/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.5.29
+
+* Pass a constant `_web_only_mapCreationId` to `platform.buildView`, so web can return a cached widget DOM when flutter attempts to repaint there.
+* Modify some examples slightly so they're more web-friendly.
+
 ## 0.5.28+2
 
 * Move test introduced in #2449 to its right location.

packages/google_maps_flutter/google_maps_flutter/example/lib/marker_icons.dart

@@ -73,7 +73,7 @@ class MarkerIconsBodyState extends State<MarkerIconsBody> {
   Future<void> _createMarkerImageFromAsset(BuildContext context) async {
     if (_markerIcon == null) {
       final ImageConfiguration imageConfiguration =
-          createLocalImageConfiguration(context);
+          createLocalImageConfiguration(context, size: Size.square(48));
       BitmapDescriptor.fromAssetImage(
               imageConfiguration, 'assets/red_square.png')
           .then(_updateBitmap);

packages/google_maps_flutter/google_maps_flutter/example/lib/place_polyline.dart

@@ -4,8 +4,7 @@
 
 // ignore_for_file: public_member_api_docs
 
-import 'dart:io' show Platform;
-
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:google_maps_flutter/google_maps_flutter.dart';
 
@@ -202,7 +201,9 @@ class PlacePolylineBodyState extends State<PlacePolylineBody> {
 
   @override
   Widget build(BuildContext context) {
-    final bool iOSorNotSelected = Platform.isIOS || (selectedPolyline == null);
+    final bool iOSorNotSelected =
+        (!kIsWeb && defaultTargetPlatform == TargetPlatform.iOS) ||
+            (selectedPolyline == null);
 
     return Column(
       mainAxisAlignment: MainAxisAlignment.spaceEvenly,

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

@@ -10,6 +10,12 @@ part of google_maps_flutter;
 /// map is created.
 typedef void MapCreatedCallback(GoogleMapController controller);
 
+// This counter is used to provide a stable "constant" initialization id
+// to the buildView function, so the web implementation can use it as a
+// cache key. This needs to be provided from the outside, because web
+// views seem to re-render much more often that mobile platform views.
+int _webOnlyMapId = 0;
+
 /// A widget which displays a map with data obtained from the Google Maps service.
 class GoogleMap extends StatefulWidget {
   /// Creates a widget displaying data from Google Maps services.
@@ -205,6 +211,8 @@ class GoogleMap extends StatefulWidget {
 }
 
 class _GoogleMapState extends State<GoogleMap> {
+  final _webOnlyMapCreationId = _webOnlyMapId++;
+
   final Completer<GoogleMapController> _controller =
       Completer<GoogleMapController>();
 
@@ -223,7 +231,9 @@ class _GoogleMapState extends State<GoogleMap> {
       'polygonsToAdd': serializePolygonSet(widget.polygons),
       'polylinesToAdd': serializePolylineSet(widget.polylines),
       'circlesToAdd': serializeCircleSet(widget.circles),
+      '_webOnlyMapCreationId': _webOnlyMapCreationId,
     };
+
     return _googleMapsFlutterPlatform.buildView(
       creationParams,
       widget.gestureRecognizers,

packages/google_maps_flutter/google_maps_flutter/pubspec.yaml

@@ -1,7 +1,7 @@
 name: google_maps_flutter
 description: A Flutter plugin for integrating Google Maps in iOS and Android applications.
 homepage: https://github.com/flutter/plugins/tree/master/packages/google_maps_flutter/google_maps_flutter
-version: 0.5.28+2
+version: 0.5.29
 
 dependencies:
   flutter:
@@ -19,6 +19,8 @@ dev_dependencies:
     sdk: flutter
   test: ^1.6.0
   pedantic: ^1.8.0
+  plugin_platform_interface: ^1.0.2
+  mockito: ^4.1.1
 
 flutter:
   plugin:

packages/google_maps_flutter/google_maps_flutter/test/map_creation_test.dart

@@ -0,0 +1,64 @@
+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:google_maps_flutter/google_maps_flutter.dart';
+import 'package:google_maps_flutter_platform_interface/google_maps_flutter_platform_interface.dart';
+import 'package:plugin_platform_interface/plugin_platform_interface.dart';
+import 'package:mockito/mockito.dart';
+
+class MockGoogleMapsFlutterPlatform extends Mock
+    with MockPlatformInterfaceMixin
+    implements GoogleMapsFlutterPlatform {}
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final platform = MockGoogleMapsFlutterPlatform();
+
+  setUp(() {
+    // Use a mock platform so we never need to hit the MethodChannel code.
+    GoogleMapsFlutterPlatform.instance = platform;
+    when(platform.buildView(any, any, any)).thenReturn(Container());
+  });
+
+  testWidgets('_webOnlyMapCreationId increments with each GoogleMap widget', (
+    WidgetTester tester,
+  ) async {
+    // Inject two map widgets...
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: Column(
+          children: const [
+            GoogleMap(
+              initialCameraPosition: CameraPosition(
+                target: LatLng(43.362, -5.849),
+              ),
+            ),
+            GoogleMap(
+              initialCameraPosition: CameraPosition(
+                target: LatLng(47.649, -122.350),
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+
+    // Verify that each one was created with a different _webOnlyMapCreationId.
+    verifyInOrder([
+      platform.buildView(
+        argThat(containsPair('_webOnlyMapCreationId', 0)),
+        any,
+        any,
+      ),
+      platform.buildView(
+        argThat(containsPair('_webOnlyMapCreationId', 1)),
+        any,
+        any,
+      ),
+    ]);
+  });
+}

packages/google_maps_flutter/google_maps_flutter_platform_interface/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.0.3
+
+* Pass icon width/height if present on `fromAssetImage` BitmapDescriptors (web only)
+
 ## 1.0.2
 
 * Update lower bound of dart dependency to 2.1.0.

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

@@ -9,6 +9,8 @@ import 'package:flutter/material.dart'
     show ImageConfiguration, AssetImage, AssetBundleImageKey;
 import 'package:flutter/services.dart' show AssetBundle;
 
+import 'package:flutter/foundation.dart' show kIsWeb;
+
 /// Defines a bitmap image. For a marker, this class can be used to set the
 /// image of the marker icon. For a ground overlay, it can be used to set the
 /// image to place on the surface of the earth.
@@ -100,6 +102,11 @@ class BitmapDescriptor {
       'fromAssetImage',
       assetBundleImageKey.name,
       assetBundleImageKey.scale,
+      if (kIsWeb && configuration?.size != null)
+        [
+          configuration.size.width,
+          configuration.size.height,
+        ],
     ]);
   }
 

packages/google_maps_flutter/google_maps_flutter_platform_interface/pubspec.yaml

@@ -3,7 +3,7 @@ description: A common platform interface for the google_maps_flutter plugin.
 homepage: https://github.com/flutter/plugins/tree/master/packages/google_maps_flutter/google_maps_flutter_platform_interface
 # 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: 1.0.2
+version: 1.0.3
 
 dependencies:
   flutter:
@@ -19,5 +19,5 @@ dev_dependencies:
   pedantic: ^1.8.0
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: ">=2.3.0 <3.0.0"
   flutter: ">=1.9.1+hotfix.4 <2.0.0"