Flutter道路距离计算插件gmaps_by_road_distance_calculator的使用

Flutter道路距离计算插件gmaps_by_road_distance_calculator的使用

功能

gmaps_by_road_distance_calculator 是一个Flutter插件，用于通过Google Maps API计算两个点之间的道路距离。它支持多种出行方式，如驾车、步行、骑行等。

开始使用

要使用此插件，您需要先获取一个Google Maps Platform API密钥。您可以在Google Cloud Console中创建一个项目并启用Maps SDK for Web和Directions API来获取API密钥。此外，您还可以根据需求选择不同的出行方式。

使用方法

以下是一个完整的示例代码，展示了如何使用gmaps_by_road_distance_calculator插件来计算两个点之间的道路距离。我们将创建一个简单的Flutter应用程序，用户可以输入起点和终点的经纬度，并选择出行方式，然后点击按钮计算距离。

import 'package:flutter/material.dart';
import 'package:gmaps_by_road_distance_calculator/gmaps_by_road_distance_calculator.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      title: '道路距离计算器',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: DistanceCalculatorPage(),
    );
  }
}

class DistanceCalculatorPage extends StatefulWidget {
  [@override](/user/override)
  _DistanceCalculatorPageState createState() => _DistanceCalculatorPageState();
}

class _DistanceCalculatorPageState extends State<DistanceCalculatorPage> {
  final TextEditingController _startLatController = TextEditingController();
  final TextEditingController _startLngController = TextEditingController();
  final TextEditingController _destLatController = TextEditingController();
  final TextEditingController _destLngController = TextEditingController();

  String _distanceResult = '';
  TravelModes _selectedTravelMode = TravelModes.driving;

  // 创建ByRoadDistanceCalculator实例
  ByRoadDistanceCalculator _distanceCalculator = ByRoadDistanceCalculator();

  Future<void> _calculateDistance() async {
    try {
      // 获取用户输入的经纬度
      double startLat = double.parse(_startLatController.text);
      double startLng = double.parse(_startLngController.text);
      double destLat = double.parse(_destLatController.text);
      double destLng = double.parse(_destLngController.text);

      // 调用getDistance方法计算距离
      var result = await _distanceCalculator.getDistance(
        'YOUR_API_KEY', // 替换为您的Google Maps API密钥
        startLat,
        startLng,
        destLat,
        destLng,
        travelMode: _selectedTravelMode,
      );

      // 更新UI显示结果
      setState(() {
        _distanceResult = '距离: ${result.distance} 米\n时长: ${result.duration}';
      });
    } catch (e) {
      // 处理异常情况
      setState(() {
        _distanceResult = '计算失败: $e';
      });
    }
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('道路距离计算器'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: [
            TextField(
              controller: _startLatController,
              decoration: InputDecoration(labelText: '起点纬度'),
              keyboardType: TextInputType.number,
            ),
            TextField(
              controller: _startLngController,
              decoration: InputDecoration(labelText: '起点经度'),
              keyboardType: TextInputType.number,
            ),
            TextField(
              controller: _destLatController,
              decoration: InputDecoration(labelText: '终点纬度'),
              keyboardType: TextInputType.number,
            ),
            TextField(
              controller: _destLngController,
              decoration: InputDecoration(labelText: '终点经度'),
              keyboardType: TextInputType.number,
            ),
            DropdownButtonFormField<TravelModes>(
              value: _selectedTravelMode,
              onChanged: (TravelModes? newValue) {
                setState(() {
                  _selectedTravelMode = newValue!;
                });
              },
              items: TravelModes.values.map((TravelModes mode) {
                return DropdownMenuItem<TravelModes>(
                  value: mode,
                  child: Text(mode.toString().split('.').last),
                );
              }).toList(),
              decoration: InputDecoration(labelText: '出行方式'),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: _calculateDistance,
              child: Text('计算距离'),
            ),
            SizedBox(height: 20),
            Text(_distanceResult),
          ],
        ),
      ),
    );
  }
}