Flutter地理位置编码插件geohash的使用

geohash 是一个用于地理编码的库，它被 Elasticsearch 等工具广泛用于地理查询。本文将介绍如何在 Flutter 中使用该库进行地理位置的编码和解码。

使用方法

以下是一个简单的使用示例：

导入依赖

首先，在 pubspec.yaml 文件中添加 geohash 依赖：

dependencies:
  geohash: ^0.0.4

然后运行 flutter pub get 来安装依赖。

编码与解码地理位置

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

void main() {
  // 初始化应用程序
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: GeoHashExample(),
    );
  }
}

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

class _GeoHashExampleState extends State<GeoHashExample> {
  String _encoded = '';
  String _decodedLat = '';
  String _decodedLng = '';

  void _encodeLocation() {
    // 编码经纬度为 geohash
    setState(() {
      _encoded = Geohash.encode(40, -120); // 示例：纽约的经纬度
    });
  }

  void _decodeLocation() {
    // 解码 geohash 为经纬度
    final decoded = Geohash.decode(_encoded);
    setState(() {
      _decodedLat = decoded.latitude.toString();
      _decodedLng = decoded.longitude.toString();
    });
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('GeoHash 示例'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            // 显示编码结果
            Text('Geohash 编码: $_encoded'),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: _encodeLocation,
              child: Text('编码位置'),
            ),
            SizedBox(height: 20),
            // 显示解码结果
            Text('解码后的纬度: $_decodedLat'),
            Text('解码后的经度: $_decodedLng'),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: _decodeLocation,
              child: Text('解码位置'),
            ),
          ],
        ),
      ),
    );
  }
}

功能和问题报告

如果需要功能请求或发现任何问题，请前往 GitHub 仓库 提交 issue。

完整示例代码

以下是完整的示例代码，可以直接运行：

// Copyright (c) 2015, <your name>. All rights reserved. Use of this source code
// is governed by a BSD-style license that can be found in the LICENSE file.

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

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

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: GeoHashExample(),
    );
  }
}

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

class _GeoHashExampleState extends State<GeoHashExample> {
  String _encoded = '';
  String _decodedLat = '';
  String _decodedLng = '';

  void _encodeLocation() {
    setState(() {
      _encoded = Geohash.encode(40, -120); // 示例：纽约的经纬度
    });
  }

  void _decodeLocation() {
    final decoded = Geohash.decode(_encoded);
    setState(() {
      _decodedLat = decoded.latitude.toString();
      _decodedLng = decoded.longitude.toString();
    });
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('GeoHash 示例'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Text('Geohash 编码: $_encoded'),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: _encodeLocation,
              child: Text('编码位置'),
            ),
            SizedBox(height: 20),
            Text('解码后的纬度: $_decodedLat'),
            Text('解码后的经度: $_decodedLng'),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: _decodeLocation,
              child: Text('解码位置'),
            ),
          ],
        ),
      ),
    );
  }
}