dart

packages/google_maps_flutter/google_maps_flutter/example/lib/main.dart

@@ -20,6 +20,7 @@ import 'place_polygon.dart';
 import 'place_polyline.dart';
 import 'scrolling_map.dart';
 import 'snapshot.dart';
+import 'tile_overlay.dart';
 
 final List<GoogleMapExampleAppPage> _allPages = <GoogleMapExampleAppPage>[
   MapUiPage(),
@@ -36,6 +37,7 @@ final List<GoogleMapExampleAppPage> _allPages = <GoogleMapExampleAppPage>[
   PaddingPage(),
   SnapshotPage(),
   LiteModePage(),
+  TileOverlayPage(),  
 ];
 
 class MapsDemo extends StatelessWidget {

packages/google_maps_flutter/google_maps_flutter/example/lib/tile_overlay.dart

@@ -0,0 +1,151 @@
+// 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.
+
+// ignore_for_file: public_member_api_docs
+
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+import 'package:flutter/material.dart';
+import 'package:google_maps_flutter/google_maps_flutter.dart';
+
+import 'page.dart';
+
+class TileOverlayPage extends GoogleMapExampleAppPage {
+  TileOverlayPage() : super(const Icon(Icons.map), 'Tile overlay');
+
+  @override
+  Widget build(BuildContext context) {
+    return const TileOverlayBody();
+  }
+}
+
+class TileOverlayBody extends StatefulWidget {
+  const TileOverlayBody();
+
+  @override
+  State<StatefulWidget> createState() => TileOverlayBodyState();
+}
+
+class TileOverlayBodyState extends State<TileOverlayBody> {
+  TileOverlayBodyState();
+
+  GoogleMapController controller;
+  TileOverlay _tileOverlay;
+
+  void _onMapCreated(GoogleMapController controller) {
+    this.controller = controller;
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+  }
+
+  void _removeTileOverlay() {
+    setState(() {
+      _tileOverlay = null;
+    });
+  }
+
+  void _addTileOverlay() {
+    final TileOverlay tileOverlay = TileOverlay(
+      tileOverlayId: TileOverlayId("tile_overlay_1"),
+      tileProvider: DebugTileProvider(),
+    );
+    setState(() {
+      _tileOverlay = tileOverlay;
+    });
+  }
+
+  void _clearTileCache() {
+    if (_tileOverlay != null && controller != null) {
+      controller.clearTileCache(_tileOverlay.tileOverlayId);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      mainAxisSize: MainAxisSize.min,
+      mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+      crossAxisAlignment: CrossAxisAlignment.stretch,
+      children: <Widget>[
+        Center(
+          child: SizedBox(
+            width: 350.0,
+            height: 300.0,
+            child: GoogleMap(
+              initialCameraPosition: const CameraPosition(
+                target: LatLng(59.935460, 30.325177),
+                zoom: 7.0,
+              ),
+              tileOverlays:
+                  _tileOverlay != null ? <TileOverlay>{_tileOverlay} : null,
+              onMapCreated: _onMapCreated,
+            ),
+          ),
+        ),
+        FlatButton(
+          child: const Text('Add tile overlay'),
+          onPressed: _addTileOverlay,
+        ),
+        FlatButton(
+          child: const Text('Remove tile overlay'),
+          onPressed: _removeTileOverlay,
+        ),
+        FlatButton(
+          child: const Text('Clear tile cache'),
+          onPressed: _clearTileCache,
+        ),
+      ],
+    );
+  }
+}
+
+class DebugTileProvider implements TileProvider {
+  DebugTileProvider() {
+    boxPaint.isAntiAlias = true;
+    boxPaint.color = Colors.blue;
+    boxPaint.strokeWidth = 2.0;
+    boxPaint.style = PaintingStyle.stroke;
+  }
+
+  static const int width = 100;
+  static const int height = 100;
+  static final Paint boxPaint = Paint();
+  static final TextStyle textStyle = TextStyle(
+    color: Colors.red,
+    fontSize: 20,
+  );
+
+  @override
+  Future<Tile> getTile(int x, int y, int zoom) async {
+    final ui.PictureRecorder recorder = ui.PictureRecorder();
+    final Canvas canvas = Canvas(recorder);
+    final TextSpan textSpan = TextSpan(
+      text: "$x,$y",
+      style: textStyle,
+    );
+    final TextPainter textPainter = TextPainter(
+      text: textSpan,
+      textDirection: TextDirection.ltr,
+    );
+    textPainter.layout(
+      minWidth: 0.0,
+      maxWidth: width.toDouble(),
+    );
+    final Offset offset = const Offset(0, 0);
+    textPainter.paint(canvas, offset);
+    canvas.drawRect(
+        Rect.fromLTRB(0, 0, width.toDouble(), width.toDouble()), boxPaint);
+    final ui.Picture picture = recorder.endRecording();
+    final Uint8List byteData = await picture
+        .toImage(width, height)
+        .then((ui.Image image) =>
+            image.toByteData(format: ui.ImageByteFormat.png))
+        .then((ByteData byteData) => byteData.buffer.asUint8List());
+    return Tile(width, height, byteData);
+  }
+}

packages/google_maps_flutter/google_maps_flutter/lib/google_maps_flutter.dart

@@ -42,7 +42,11 @@ export 'package:google_maps_flutter_platform_interface/google_maps_flutter_platf
         PolygonId,
         Polyline,
         PolylineId,
-        ScreenCoordinate;
+        ScreenCoordinate,
+        Tile,
+        TileOverlayId,
+        TileOverlay,
+        TileProvider;
 
 part 'src/controller.dart';
 part 'src/google_map.dart';

packages/google_maps_flutter/google_maps_flutter/lib/src/controller.dart

@@ -18,6 +18,8 @@ class GoogleMapController {
     @required this.mapId,
   }) : assert(_googleMapsFlutterPlatform != null) {
     _connectStreams(mapId);
+    _googleMapsFlutterPlatform.setGetTileCallback(
+        mapId: mapId, callback: _googleMapState._onGetTile);
   }
 
   /// Initialize control of a [GoogleMap] with [id].
@@ -152,6 +154,32 @@ class GoogleMapController {
         mapId: mapId);
   }
 
+  /// Updates tile overlays configuration.
+  ///
+  /// Change listeners are notified once the update has been made on the
+  /// platform side.
+  ///
+  /// The returned [Future] completes after listeners have been notified.
+  Future<void> _updateTileOverlays(TileOverlayUpdates tileOverlayUpdates) {
+    assert(tileOverlayUpdates != null);
+    return _googleMapsFlutterPlatform.updateTileOverlays(tileOverlayUpdates,
+        mapId: mapId);
+  }
+
+  /// Clears the tile cache so that all tiles will be requested again from the
+  /// [TileProvider].
+  ///
+  /// The current tiles from this tile overlay will also be
+  /// cleared from the map after calling this method. The API maintains a small
+  /// in-memory cache of tiles. If you want to cache tiles for longer, you
+  /// should implement an on-disk cache.
+  Future<void> clearTileCache(TileOverlayId tileOverlayId) async {
+    assert(tileOverlayId != null);
+    return _googleMapsFlutterPlatform.clearTileCache(tileOverlayId,
+        mapId: mapId);
+  }
+
+
   /// Starts an animated change of the map camera position.
   ///
   /// The returned [Future] completes after the change has been started on the

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

@@ -50,6 +50,7 @@ class GoogleMap extends StatefulWidget {
     this.polylines,
     this.circles,
     this.onCameraMoveStarted,
+    this.tileOverlays,
     this.onCameraMove,
     this.onCameraIdle,
     this.onTap,
@@ -120,6 +121,9 @@ class GoogleMap extends StatefulWidget {
   /// Circles to be placed on the map.
   final Set<Circle> circles;
 
+  /// Tile overlays to be placed on the map.
+  final Set<TileOverlay> tileOverlays;
+
   /// Called when the camera starts moving.
   ///
   /// This can be initiated by the following:
@@ -220,6 +224,7 @@ class _GoogleMapState extends State<GoogleMap> {
   Map<PolygonId, Polygon> _polygons = <PolygonId, Polygon>{};
   Map<PolylineId, Polyline> _polylines = <PolylineId, Polyline>{};
   Map<CircleId, Circle> _circles = <CircleId, Circle>{};
+  Map<TileOverlayId, TileOverlay> _tileOverlays = <TileOverlayId, TileOverlay>{};
   _GoogleMapOptions _googleMapOptions;
 
   @override
@@ -232,6 +237,7 @@ class _GoogleMapState extends State<GoogleMap> {
       'polylinesToAdd': serializePolylineSet(widget.polylines),
       'circlesToAdd': serializeCircleSet(widget.circles),
       '_webOnlyMapCreationId': _webOnlyMapCreationId,
+      'tileOverlaysToAdd': serializeTileOverlaySet(widget.tileOverlays),
     };
 
     return _googleMapsFlutterPlatform.buildView(
@@ -249,6 +255,7 @@ class _GoogleMapState extends State<GoogleMap> {
     _polygons = keyByPolygonId(widget.polygons);
     _polylines = keyByPolylineId(widget.polylines);
     _circles = keyByCircleId(widget.circles);
+    _tileOverlays = keyTileOverlayId(widget.tileOverlays);
   }
 
   @override
@@ -266,6 +273,7 @@ class _GoogleMapState extends State<GoogleMap> {
     _updatePolygons();
     _updatePolylines();
     _updateCircles();
+    _updateTileOverlays();
   }
 
   void _updateOptions() async {
@@ -313,6 +321,14 @@ class _GoogleMapState extends State<GoogleMap> {
     _circles = keyByCircleId(widget.circles);
   }
 
+  void _updateTileOverlays() async {
+    final GoogleMapController controller = await _controller.future;
+    // ignore: unawaited_futures
+    controller._updateTileOverlays(TileOverlayUpdates.from(
+        _tileOverlays.values.toSet(), widget.tileOverlays));
+    _tileOverlays = keyTileOverlayId(widget.tileOverlays);
+  }
+
   Future<void> onPlatformViewCreated(int id) async {
     final GoogleMapController controller = await GoogleMapController.init(
       id,
@@ -376,6 +392,21 @@ class _GoogleMapState extends State<GoogleMap> {
       widget.onLongPress(position);
     }
   }
+
+  // Returns the [Tile] from an added [TileOverlay].
+  //
+  // If the TileOverlay or his TileProvider is not found,
+  // a [TileProvider.noTile] is returned.
+  Future<Tile> _onGetTile(
+      String tileOverlayIdRaw, int x, int y, int zoom) async {
+    assert(tileOverlayIdRaw != null);
+    final TileOverlayId tileOverlayId = TileOverlayId(tileOverlayIdRaw);
+    final TileOverlay tileOverlay = _tileOverlays[tileOverlayId];
+    if (tileOverlay == null || tileOverlay.tileProvider == null) {
+      return null;
+    }
+    return await tileOverlay.tileProvider.getTile(x, y, zoom);
+  }
 }
 
 /// Configuration options for the GoogleMaps user interface.

packages/google_maps_flutter/google_maps_flutter/pubspec.yaml

@@ -7,7 +7,8 @@ dependencies:
   flutter:
     sdk: flutter
   flutter_plugin_android_lifecycle: ^1.0.0
-  google_maps_flutter_platform_interface: ^1.1.0
+  google_maps_flutter_platform_interface:
+    path: ../google_maps_flutter_platform_interface
 
 dev_dependencies:
   flutter_test: