Flutter路线规划插件flutter_polyline_points的使用

flutter_polyline_points

flutter_polyline_points 是一个Flutter插件，它可以将Google编码的polyline字符串解码为适合在地图上显示路线/多段线的地理坐标列表。

开始使用

这个包包含了函数用于解码Google编码的polyline字符串，返回一个表示两个地理位置之间路径的坐标列表。

添加依赖

要使用此包，请按照官方文档中的说明，在pubspec.yaml文件中添加flutter_polyline_points作为依赖项。

dependencies:
  flutter_polyline_points: ^latest_version # 替换为最新版本号

导入包

在Dart文件中导入包：

import 'package:flutter_polyline_points/flutter_polyline_points.dart';

使用方法

方法一：通过地理坐标获取点列表

该方法根据地理坐标返回PolylineResult实例，其中包含API状态、错误信息以及解码后的点列表。

PolylinePoints polylinePoints = PolylinePoints();
PolylineResult result = await polylinePoints.getRouteBetweenCoordinates(
  googleApiKey: "YOUR_GOOGLE_API_KEY",
  request: PolylineRequest(
    origin: PointLatLng(_originLatitude, _originLongitude),
    destination: PointLatLng(_destLatitude, _destLongitude),
    mode: TravelMode.driving,
    wayPoints: [PolylineWayPoint(location: "Sabo, Yaba Lagos Nigeria")],
  ),
);
print(result.points);

方法二：解码编码的polyline字符串

直接解码给定的Google polyline字符串。

List<PointLatLng> result = polylinePoints.decodePolyline("_p~iF~ps|U_ulLnnqC_mqNvxq`@");
print(result);

方法三：获取带有替代路线的polyline

此方法返回多个PolylineResult，每个代表一条可能的路线。

List<PolylineResult> results = await PolylinePoints().getRouteBetweenCoordinates(
  googleApiKey: "YOUR_GOOGLE_API_KEY",
  request: PolylineRequest(
    origin: PointLatLng(_originLatitude, _originLongitude),
    destination: PointLatLng(_destLatitude, _destLongitude),
    mode: TravelMode.driving,
    wayPoints: [PolylineWayPoint(location: "Sabo, Yaba Lagos Nigeria")],
  ),
);
print(results.length);

提示

请确保使用有效的Google API密钥。如果需要帮助生成API密钥，请访问官方文档。

完整示例代码

下面是一个完整的示例应用程序，它展示了如何在地图上绘制路线。

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:flutter_polyline_points/flutter_polyline_points.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Polyline example',
      theme: ThemeData(
        primarySwatch: Colors.orange,
      ),
      home: MapScreen(),
    );
  }
}

class MapScreen extends StatefulWidget {
  @override
  _MapScreenState createState() => _MapScreenState();
}

class _MapScreenState extends State<MapScreen> {
  late GoogleMapController mapController;
  double _originLatitude = 6.5212402, _originLongitude = 3.3679965;
  double _destLatitude = 6.849660, _destLongitude = 3.648190;
  Map<MarkerId, Marker> markers = {};
  Map<PolylineId, Polyline> polylines = {};
  List<LatLng> polylineCoordinates = [];
  PolylinePoints polylinePoints = PolylinePoints();
  String googleAPiKey = "YOUR_GOOGLE_API_KEY";

  @override
  void initState() {
    super.initState();

    // 添加起点标记
    _addMarker(LatLng(_originLatitude, _originLongitude), "origin", BitmapDescriptor.defaultMarker);

    // 添加终点标记
    _addMarker(LatLng(_destLatitude, _destLongitude), "destination", BitmapDescriptor.defaultMarkerWithHue(90));
    _getPolyline();
  }

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Scaffold(
        body: GoogleMap(
          initialCameraPosition: CameraPosition(
            target: LatLng(_originLatitude, _originLongitude),
            zoom: 15,
          ),
          myLocationEnabled: true,
          tiltGesturesEnabled: true,
          compassEnabled: true,
          scrollGesturesEnabled: true,
          zoomGesturesEnabled: true,
          onMapCreated: _onMapCreated,
          markers: Set<Marker>.of(markers.values),
          polylines: Set<Polyline>.of(polylines.values),
        ),
      ),
    );
  }

  void _onMapCreated(GoogleMapController controller) async {
    mapController = controller;
  }

  void _addMarker(LatLng position, String id, BitmapDescriptor descriptor) {
    MarkerId markerId = MarkerId(id);
    Marker marker = Marker(markerId: markerId, icon: descriptor, position: position);
    markers[markerId] = marker;
  }

  void _addPolyLine() {
    PolylineId id = PolylineId("poly");
    Polyline polyline = Polyline(polylineId: id, color: Colors.red, points: polylineCoordinates);
    polylines[id] = polyline;
    setState(() {});
  }

  Future<void> _getPolyline() async {
    PolylineResult result = await polylinePoints.getRouteBetweenCoordinates(
      googleApiKey: googleAPiKey,
      request: PolylineRequest(
        origin: PointLatLng(_originLatitude, _originLongitude),
        destination: PointLatLng(_destLatitude, _destLongitude),
        mode: TravelMode.driving,
        wayPoints: [PolylineWayPoint(location: "Sabo, Yaba Lagos Nigeria")],
      ),
    );

    if (result.points.isNotEmpty) {
      result.points.forEach((PointLatLng point) {
        polylineCoordinates.add(LatLng(point.latitude, point.longitude));
      });
    }
    _addPolyLine();
  }
}

以上代码创建了一个简单的Flutter应用，该应用在地图上显示了从起点到终点的路线，并且可以在地图上看到起点和终点的标记。请确保替换YOUR_GOOGLE_API_KEY为您自己的Google API密钥。