Flutter地图路径绘制插件flutter_polyline_points_plus的使用

描述

flutter_polyline_points_plus是flutter_polyline_points的一个分支，它提供了将Google Polyline编码字符串解码为地理坐标列表的功能。此分支的目的是确保插件保持更新，因为原始作者不再维护该插件。

感谢@shkvoretz对Flutter SDK的升级。

开始使用

添加依赖

要使用这个包，在您的pubspec.yaml文件中添加flutter_polyline_points_plus作为依赖项。

dependencies:
  flutter_polyline_points_plus: ^latest_version

导入包

在您的Dart文件中导入flutter_polyline_points_plus：

import 'package:flutter_polyline_points_plus/flutter_polyline_points_plus.dart';

使用方法

第一种方法：通过地理坐标获取路径点

可以通过给定的起点和终点坐标来获取路径点。这会返回一个PolylineResult实例，其中包含API的状态、错误信息以及解码后的点列表。

PolylinePoints polylinePoints = PolylinePoints();
PolylineResult result = await polylinePoints.getRouteBetweenCoordinates(
    googleAPiKey,
    _originLatitude, 
    _originLongitude, 
    _destLatitude, 
    _destLongitude);
print(result.points);

第二种方法：解码Google Polyline编码字符串

可以解码Google提供的Polyline编码字符串（如_p~iF~ps|U_ulLnnqC_mqNvxq@）以获得路径点列表。

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

提示

请确保使用有效的Google API密钥。如果您需要帮助生成项目所需的API密钥，请点击此链接

示例代码

以下是一个完整的示例应用程序，展示了如何在地图上显示路径。

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:flutter_polyline_points_plus/flutter_polyline_points_plus.dart';
import 'package:flutter_dotenv/flutter_dotenv.dart';

void main() async {
  await dotenv.load(fileName: "env/.env");
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

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

class MapScreen extends StatefulWidget {
  const MapScreen({super.key});

  @override
  State<MapScreen> createState() => _MapScreenState();
}

class _MapScreenState extends State<MapScreen> {
  late GoogleMapController mapController;
  final double _originLatitude = 26.48424, _originLongitude = 50.04551;
  final double _destLatitude = 26.46423, _destLongitude = 50.06358;
  Map<MarkerId, Marker> markers = {};
  Map<PolylineId, Polyline> polylines = {};
  List<LatLng> polylineCoordinates = [];
  PolylinePoints polylinePoints = PolylinePoints();

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

  Future<void> _getPolyline() async {
    final googleAPiKey = dotenv.get("GOOGLE_API_KEY");
    assert(googleAPiKey.isNotEmpty, "Please add your google api key on .env");

    PolylineResult result = await polylinePoints.getRouteBetweenCoordinates(
        googleAPiKey,
        PointLatLng(_originLatitude, _originLongitude),
        PointLatLng(_destLatitude, _destLongitude),
        travelMode: TravelMode.driving,
        wayPoints: [PolylineWayPoint(location: "Sabo, Yaba Lagos Nigeria")]);

    if (result.points.isNotEmpty) {
      for (var point in result.points) {
        polylineCoordinates.add(LatLng(point.latitude, point.longitude));
      }
    }
    _addPolyLine();
  }
}

这个例子展示了如何在地图上绘制从起点到终点的路径，并且包含了必要的设置和配置。您可以根据自己的需求调整经纬度和其他参数。