299 lines
10 KiB
Dart
299 lines
10 KiB
Dart
// lib/utils/location_helper.dart
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import 'dart:async';
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import 'dart:math';
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import 'package:flutter/material.dart';
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import 'package:geolocator/geolocator.dart';
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import 'package:qhd_prevention/customWidget/custom_alert_dialog.dart';
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import 'package:qhd_prevention/customWidget/toast_util.dart';
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import 'package:shared_preferences/shared_preferences.dart';
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/// ============ 常量与坐标转换相关（WGS84/GCJ02/BD09） ============
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const double _pi = 3.1415926535897932384626;
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const double _xPi = _pi * 3000.0 / 180.0;
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const double _a = 6378245.0;
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const double _ee = 0.006693421622965943;
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/// 判断是否在中国境内（仅中国境内需要偏移处理）
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bool _outOfChina(double lat, double lon) {
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if (lon < 72.004 || lon > 137.8347) return true;
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if (lat < 0.8293 || lat > 55.8271) return true;
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return false;
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}
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double _transformLat(double x, double y) {
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double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * sqrt(x.abs());
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ret += (20.0 * sin(6.0 * x * _pi) + 20.0 * sin(2.0 * x * _pi)) * 2.0 / 3.0;
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ret += (20.0 * sin(y * _pi) + 40.0 * sin(y / 3.0 * _pi)) * 2.0 / 3.0;
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ret += (160.0 * sin(y / 12.0 * _pi) + 320.0 * sin(y * _pi / 30.0)) * 2.0 / 3.0;
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return ret;
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}
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double _transformLon(double x, double y) {
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double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * sqrt(x.abs());
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ret += (20.0 * sin(6.0 * x * _pi) + 20.0 * sin(2.0 * x * _pi)) * 2.0 / 3.0;
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ret += (20.0 * sin(x * _pi) + 40.0 * sin(x / 3.0 * _pi)) * 2.0 / 3.0;
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ret += (150.0 * sin(x / 12.0 * _pi) + 300.0 * sin(x / 30.0 * _pi)) * 2.0 / 3.0;
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return ret;
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}
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/// WGS84 -> GCJ02
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List<double> wgs84ToGcj02(double lat, double lon) {
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if (_outOfChina(lat, lon)) return [lat, lon];
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double dLat = _transformLat(lon - 105.0, lat - 35.0);
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double dLon = _transformLon(lon - 105.0, lat - 35.0);
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double radLat = lat / 180.0 * _pi;
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double magic = sin(radLat);
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magic = 1 - _ee * magic * magic;
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double sqrtMagic = sqrt(magic);
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dLat = (dLat * 180.0) / ((_a * (1 - _ee)) / (magic * sqrtMagic) * _pi);
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dLon = (dLon * 180.0) / ((_a / sqrtMagic) * cos(radLat) * _pi);
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double mgLat = lat + dLat;
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double mgLon = lon + dLon;
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return [mgLat, mgLon];
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}
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/// GCJ02 -> BD09
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List<double> gcj02ToBd09(double lat, double lon) {
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double x = lon;
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double y = lat;
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double z = sqrt(x * x + y * y) + 0.00002 * sin(y * _xPi);
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double theta = atan2(y, x) + 0.000003 * cos(x * _xPi);
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double bdLon = z * cos(theta) + 0.0065;
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double bdLat = z * sin(theta) + 0.006;
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return [bdLat, bdLon];
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}
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/// 直接 WGS84 -> BD09（先 WGS84->GCJ02，再 GCJ02->BD09）
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List<double> wgs84ToBd09(double lat, double lon) {
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final gcj = wgs84ToGcj02(lat, lon);
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return gcj02ToBd09(gcj[0], gcj[1]);
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}
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/// ============ 定位相关设置 ============
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/// 定位请求超时时间（可根据需要调整）
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const Duration _locationTimeout = Duration(seconds: 10);
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/// ============ 新增：获取 Position（带权限/超时/后备策略） ============
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/// 返回 Position（WGS84）
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Future<Position> getPositionFromGeolocator({
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LocationAccuracy accuracy = LocationAccuracy.high,
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}) async {
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// 1. 权限检查与请求（先请求权限）
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LocationPermission permission = await Geolocator.checkPermission();
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if (permission == LocationPermission.denied) {
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permission = await Geolocator.requestPermission();
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if (permission == LocationPermission.denied) {
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// 用户拒绝（不是永久拒绝）
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throw Exception('定位权限被用户拒绝');
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}
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}
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if (permission == LocationPermission.deniedForever) {
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// 永久拒绝（需要用户手动到设置开启）
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throw Exception('定位权限被永久拒绝');
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}
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// 2. 检查定位服务是否开启（GPS/定位开关）
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bool serviceEnabled = await Geolocator.isLocationServiceEnabled();
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if (!serviceEnabled) {
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throw Exception('定位服务未开启');
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}
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// 3. 尝试获取当前位置（主方案：getCurrentPosition，带超时）
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Position? position;
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try {
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position = await Geolocator.getCurrentPosition(desiredAccuracy: accuracy)
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.timeout(_locationTimeout);
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} on TimeoutException catch (_) {
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position = null;
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} catch (_) {
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position = null;
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}
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// 4. 后备：尝试 getLastKnownPosition（可能是旧位置）
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if (position == null) {
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try {
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position = await Geolocator.getLastKnownPosition();
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} catch (_) {
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position = null;
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}
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}
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// 5. 后备：在 Android 上尝试 forceAndroidLocationManager（某些设备/厂商兼容性问题）
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if (position == null) {
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try {
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position = await Geolocator.getCurrentPosition(
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desiredAccuracy: accuracy,
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forceAndroidLocationManager: true,
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).timeout(_locationTimeout);
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} catch (_) {
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position = null;
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}
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}
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// 6. 最终仍无位置 -> 抛异常
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if (position == null) {
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throw Exception('无法获取位置信息，请检查设备定位设置或权限');
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}
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return position;
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}
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/// 获取 BD09 坐标（保持向后兼容：仍然返回 [bdLat, bdLon]）
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/// 内部改为调用 getPositionFromGeolocator 并转换
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Future<List<double>> getBd09FromGeolocator({
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LocationAccuracy accuracy = LocationAccuracy.high,
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}) async {
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final pos = await getPositionFromGeolocator(accuracy: accuracy);
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return wgs84ToBd09(pos.latitude, pos.longitude);
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}
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/// ============ 错误提示（中文映射） ============
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String _mapExceptionToChineseMessage(Object e) {
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final msg = e?.toString() ?? '';
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if (msg.contains('定位权限被用户拒绝') || msg.contains('Location permissions are denied') || msg.contains('denied')) {
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return '定位权限被拒绝，请允许应用获取定位权限。';
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}
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if (msg.contains('定位权限被永久拒绝') || msg.contains('deniedForever') || msg.contains('permanently denied')) {
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return '定位权限被永久拒绝，请到系统设置手动开启定位权限。';
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}
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if (msg.contains('定位服务未开启') || msg.contains('Location services are disabled')) {
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return '设备定位功能未开启，请打开系统定位后重试。';
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}
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if (msg.contains('无法获取位置信息') || msg.contains('无法获取位置信息')) {
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return '无法获取有效定位，请检查网络/GPS并重试（可尝试切换到高精度模式）。';
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}
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// 默认返回空字符串，调用方根据空串决定是否显示
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return '定位失败：${msg.replaceAll('Exception: ', '')}';
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}
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/// 点位数组计算中心点
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Map<String, double> geographicCentroid(List<dynamic> points) {
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if (points.isEmpty) {
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throw ArgumentError('points 不能为空');
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}
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double x = 0.0, y = 0.0, z = 0.0;
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double altSum = 0.0;
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int altCount = 0;
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for (var p in points) {
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final lon = p[0];
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final lat = p[1];
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final latR = lat * pi / 180.0;
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final lonR = lon * pi / 180.0;
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final cx = cos(latR) * cos(lonR);
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final cy = cos(latR) * sin(lonR);
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final cz = sin(latR);
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x += cx;
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y += cy;
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z += cz;
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if (p.length > 2 && p[2] != null) {
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altSum += p[2];
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altCount++;
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}
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}
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final cnt = points.length.toDouble();
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x /= cnt;
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y /= cnt;
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z /= cnt;
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final hyp = sqrt(x * x + y * y);
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final centroidLat = atan2(z, hyp) * 180.0 / pi;
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final centroidLon = atan2(y, x) * 180.0 / pi;
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final result = <String, double>{
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'lon': centroidLon,
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'lat': centroidLat,
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};
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if (altCount > 0) {
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result['alt'] = altSum / altCount;
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}
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return result;
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}
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/// ============ 主业务方法：获取并保存 BD09（同时处理 UI 提示/引导） ============
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/// 现在会同时保存：WGS84（原始） / GCJ02 / BD09，以及保存时间戳（bd_saved_at）
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Future<void> fetchAndSaveBd09(BuildContext context) async {
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try {
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// 获取原始位置（WGS84）
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final Position position = await getPositionFromGeolocator();
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final double wgsLat = position.latitude;
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final double wgsLon = position.longitude;
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// 计算 GCJ02（在中国境内会偏移，否则返回原始）
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final gcj = wgs84ToGcj02(wgsLat, wgsLon);
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final double gcjLat = gcj[0];
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final double gcjLon = gcj[1];
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// 计算 BD09
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final bd = gcj02ToBd09(gcjLat, gcjLon);
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final double bdLat = bd[0];
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final double bdLon = bd[1];
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// 保存到 SharedPreferences（同时保存原始 WGS84、GCJ02、BD09，以及保存时间）
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final prefs = await SharedPreferences.getInstance();
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await prefs.setString('wgs84_lat', wgsLat.toString());
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await prefs.setString('wgs84_lon', wgsLon.toString());
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await prefs.setString('gcj02_lat', gcjLat.toString());
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await prefs.setString('gcj02_lon', gcjLon.toString());
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await prefs.setString('bd_lat', bdLat.toString());
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await prefs.setString('bd_lon', bdLon.toString());
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await prefs.setInt('bd_saved_at', DateTime.now().millisecondsSinceEpoch);
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// 成功提示（按需开启）
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// ToastUtil.showNormal(context, '定位成功：$bdLat, $bdLon');
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} on Exception catch (e) {
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final msg = e.toString();
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// 定位权限被永久拒绝 -> 引导用户打开应用设置
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if (msg.contains('定位权限被永久拒绝') || msg.contains('deniedForever') || msg.contains('permanently denied')) {
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final open = await CustomAlertDialog.showConfirm(
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context,
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title: '定位权限',
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content: '定位权限被永久拒绝，需要手动到应用设置开启定位权限，是否现在打开设置？',
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cancelText: '取消',
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confirmText: '去设置',
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);
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if (open == true) {
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await Geolocator.openAppSettings();
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}
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}
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// 定位服务未开启 -> 引导用户打开系统定位设置
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else if (msg.contains('定位服务未开启') || msg.contains('Location services are disabled')) {
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final open = await CustomAlertDialog.showConfirm(
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context,
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title: '打开定位',
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content: '检测到设备定位服务未开启，是否打开系统定位设置？',
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cancelText: '取消',
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confirmText: '去打开',
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);
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if (open == true) {
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await Geolocator.openLocationSettings();
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}
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}
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// 其它错误 -> 以 toast 显示中文提示（如果映射为空则显示原错误）
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else {
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final userMsg = _mapExceptionToChineseMessage(e);
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if (userMsg.isNotEmpty) {
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// ToastUtil.showError(context, userMsg);
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} else {
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// ToastUtil.showError(context, '定位失败：${e.toString()}');
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}
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}
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} catch (e) {
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// 捕获任何未预期异常
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// ToastUtil.showError(context, '发生未知错误：${e.toString()}');
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} finally {
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// 如需隐藏 loading 可在此处处理
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}
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}
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