Add Polyline

flutter_map/lib/flutter_map.dart

@@ -10,6 +10,7 @@ import 'package:flutter_map/src/map/map.dart';
 export 'src/layer/layer.dart';
 export 'src/layer/tile_layer.dart';
 export 'src/layer/marker_layer.dart';
+export 'src/layer/polyline_layer.dart';
 export 'src/map/map.dart';
 
 class FlutterMap extends StatefulWidget {
@@ -58,6 +59,9 @@ class _FlutterMapState extends State<FlutterMap>
     if (options is MarkerLayerOptions) {
       return new MarkerLayer(options, mapState);
     }
+    if (options is PolylineLayerOptions) {
+      return new PolylineLayer(options,mapState);;
+    }
     return null;
   }
 }

flutter_map/lib/src/layer/polyline_layer.dart

@@ -0,0 +1,84 @@
+import 'package:flutter/widgets.dart';
+import 'package:latlong/latlong.dart';
+import 'package:flutter_map/flutter_map.dart';
+import 'dart:ui';
+
+
+class PolylineLayerOptions extends LayerOptions {
+  final List<Polyline> polylines;
+  PolylineLayerOptions({this.polylines = const []});
+}
+
+class Polyline {
+  final List<LatLng> points;
+  List<Offset> offsets;
+  final double strokeWidth;
+  final Color color;
+  Polyline({
+    this.points,
+    this.strokeWidth = 1.0,
+    this.color = const Color(0xFF00FF00),
+  });
+}
+
+class PolylineLayer extends StatelessWidget {
+  final PolylineLayerOptions polylineOpts;
+  final MapState map;
+  PolylineLayer(this.polylineOpts, this.map);
+
+  Widget build(BuildContext context) {
+    return new StreamBuilder<int>(
+      stream: map.onMoved, // a Stream<int> or null
+      builder: (BuildContext context, AsyncSnapshot<int> snapshot) {
+        for (var polylineOpt in this.polylineOpts.polylines) {
+          polylineOpt.offsets = [];
+          var i = 0;
+          for (var point in polylineOpt.points) {
+            i++;
+            var pos = map.project(point);
+            pos = pos.multiplyBy(map.getZoomScale(map.zoom, map.zoom)) -
+                map.getPixelOrigin();
+            polylineOpt.offsets.add(new Offset(pos.x, pos.y));
+            if (i != 1 && i != polylineOpt.points.length) {
+              polylineOpt.offsets.add(new Offset(pos.x, pos.y));
+            }
+          }
+        }
+        var polylines = <Widget>[];
+        for (var polylineOpt in this.polylineOpts.polylines) {
+          polylines.add(
+            new CustomPaint(
+                painter: new PolylinePainter(polylineOpt),
+                child: new Container(
+                  child: new Text(
+                      "                                                                                                   "),
+                )),
+          );
+        }
+        return new Container(
+          child: new Stack(
+            children: polylines,
+          ),
+        );
+      },
+    );
+  }
+}
+
+class PolylinePainter extends CustomPainter {
+  final Polyline polylineOpt;
+  PolylinePainter(this.polylineOpt);
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    if (polylineOpt.offsets == null) {
+      return;
+    }
+    final Paint paint = new Paint()..color = polylineOpt.color;
+    paint.strokeWidth = polylineOpt.strokeWidth;
+    canvas.drawPoints(PointMode.lines, polylineOpt.offsets, paint);
+  }
+
+  @override
+  bool shouldRepaint(PolylinePainter other) => false;
+}