Add a gestureRecognizers parameter to GoogleMap.

These gesture recognizers participates in gesture arenas on behalf of
the map.
This allows fine grain control over which gestures are dispatched to
the map.

Author: amirh

packages/google_maps_flutter/example/lib/main.dart

@@ -8,12 +8,14 @@ import 'map_ui.dart';
 import 'move_camera.dart';
 import 'page.dart';
 import 'place_marker.dart';
+import 'scrolling_map.dart';
 
 final List<Page> _allPages = <Page>[
   MapUiPage(),
   AnimateCameraPage(),
   MoveCameraPage(),
   PlaceMarkerPage(),
+  ScrollingMapPage(),
 ];
 
 class MapsDemo extends StatelessWidget {

packages/google_maps_flutter/example/lib/scrolling_map.dart

@@ -0,0 +1,125 @@
+// 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/gestures.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:google_maps_flutter/google_maps_flutter.dart';
+
+import 'page.dart';
+
+class ScrollingMapPage extends Page {
+  ScrollingMapPage() : super(const Icon(Icons.list), 'Scrolling map');
+
+  @override
+  Widget build(BuildContext context) {
+    return const ScrollingMapBody();
+  }
+}
+
+class ScrollingMapBody extends StatelessWidget {
+  const ScrollingMapBody();
+
+  final LatLng center = const LatLng(32.080664, 34.9563837);
+
+  @override
+  Widget build(BuildContext context) {
+    return ListView(
+      children: <Widget>[
+        new Card(
+          child: new Padding(
+            padding: const EdgeInsets.symmetric(vertical: 30.0),
+            child: new Column(
+              children: <Widget>[
+                const Padding(
+                  padding: EdgeInsets.only(bottom: 12.0),
+                  child: Text('This map consumes all touch events.'),
+                ),
+                Center(
+                  child: SizedBox(
+                    width: 300.0,
+                    height: 300.0,
+                    child: GoogleMap(
+                      onMapCreated: onMapCreated,
+                      options: new GoogleMapOptions(
+                        cameraPosition: CameraPosition(
+                          target: center,
+                          zoom: 11.0,
+                        ),
+                      ),
+                      gestureRecognizers: <OneSequenceGestureRecognizer>[
+                        new EagerGestureRecognizer()
+                      ],
+                    ),
+                  ),
+                ),
+              ],
+            ),
+          ),
+        ),
+        new Card(
+          child: new Padding(
+            padding: const EdgeInsets.symmetric(vertical: 30.0),
+            child: new Column(
+              children: <Widget>[
+                const Text('This map doesn\'t consume the vertical drags.'),
+                const Padding(
+                  padding: EdgeInsets.only(bottom: 12.0),
+                  child: Text('It still gets other gestures (e.g scale or tap).'),
+                ),
+                Center(
+                  child: SizedBox(
+                    width: 300.0,
+                    height: 300.0,
+                    child: GoogleMap(
+                      onMapCreated: onMapCreated,
+                      options: new GoogleMapOptions(
+                        cameraPosition: CameraPosition(
+                          target: center,
+                          zoom: 11.0,
+                        ),
+                      ),
+                      gestureRecognizers: <OneSequenceGestureRecognizer>[
+                        ScaleGestureRecognizer()
+                      ],
+                    ),
+                  ),
+                ),
+              ],
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+
+  void onMapCreated(GoogleMapController controller) {
+    controller.addMarker(MarkerOptions(
+      position: LatLng(
+        center.latitude,
+        center.longitude,
+      ),
+      infoWindowText: const InfoWindowText('An interesting location', '*'),
+    ));
+  }
+}
+
+class EagerGestureRecognizer extends OneSequenceGestureRecognizer {
+  @override
+  void addPointer(PointerDownEvent event) {
+    startTrackingPointer(event.pointer);
+  }
+
+  @override
+  String get debugDescription => 'eager';
+
+  @override
+  void didStopTrackingLastPointer(int pointer) {}
+
+  @override
+  void handleEvent(PointerEvent event) {
+    resolve(GestureDisposition.accepted);
+    stopTrackingPointer(event.pointer);
+  }
+}

packages/google_maps_flutter/lib/google_maps_flutter.dart

@@ -8,6 +8,7 @@ import 'dart:async';
 import 'dart:ui';
 
 import 'package:flutter/foundation.dart';
+import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 

packages/google_maps_flutter/lib/src/google_map.dart

@@ -1,14 +1,34 @@
+// 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.
+
 part of google_maps_flutter;
 
 typedef void MapCreatedCallback(GoogleMapController controller);
 
 class GoogleMap extends StatefulWidget {
-  GoogleMap({@required this.onMapCreated, GoogleMapOptions options})
-      : this.options = GoogleMapOptions.defaultOptions.copyWith(options);
+  GoogleMap({
+    @required this.onMapCreated,
+    GoogleMapOptions options,
+    this.gestureRecognizers = const <OneSequenceGestureRecognizer>[],
+  })  : assert(gestureRecognizers != null),
+        this.options = GoogleMapOptions.defaultOptions.copyWith(options);
 
   final MapCreatedCallback onMapCreated;
+
   final GoogleMapOptions options;
 
+  /// Which gestures should be consumed by the map.
+  ///
+  /// It is possible for other gesture recognizers to be competing with the map on pointer
+  /// events, e.g if the map is inside a [ListView] the [ListView] will want to handle
+  /// vertical drags. The map will claim gestures that are recognized by any of the
+  /// recognizers on this list.
+  ///
+  /// When this list is empty, the map will only handle pointer events for gestures that
+  /// were not claimed by any other gesture recognizer.
+  final List<OneSequenceGestureRecognizer> gestureRecognizers;
+
   @override
   State createState() => new _GoogleMapState();
 }
@@ -20,6 +40,7 @@ class _GoogleMapState extends State<GoogleMap> {
       return AndroidView(
         viewType: 'plugins.flutter.io/google_maps',
         onPlatformViewCreated: onPlatformViewCreated,
+        gestureRecognizers: widget.gestureRecognizers,
         creationParams: widget.options._toJson(),
         creationParamsCodec: const StandardMessageCodec(),
       );