feat: optimize map zoom calculation and added location update

lib/screens/history_screen.dart

@@ -1,3 +1,4 @@
+import 'dart:math' as math;
 import 'package:flutter/material.dart';
 import 'package:flutter_map/flutter_map.dart';
 import 'package:latlong2/latlong.dart';
@@ -256,6 +257,66 @@ class HistoryScreenState extends State<HistoryScreen> {
     }
   }
 
+  double _calculateOptimalZoom(List<LatLng> positions, {double containerWidth = 400, double containerHeight = 220}) {
+    if (positions.isEmpty) return 15.0;
+    if (positions.length == 1) return 17.0;
+
+    double minLat = positions[0].latitude;
+    double maxLat = positions[0].latitude;
+    double minLng = positions[0].longitude;
+    double maxLng = positions[0].longitude;
+
+    for (final pos in positions) {
+      minLat = math.min(minLat, pos.latitude);
+      maxLat = math.max(maxLat, pos.latitude);
+      minLng = math.min(minLng, pos.longitude);
+      maxLng = math.max(maxLng, pos.longitude);
+    }
+
+    double latToY(double lat) {
+      final latRad = lat * math.pi / 180.0;
+      return math.log(math.tan(latRad) + 1.0/math.cos(latRad));
+    }
+
+    double lngToX(double lng) {
+      return lng * math.pi / 180.0;
+    }
+
+    final minX = lngToX(minLng);
+    final maxX = lngToX(maxLng);
+    final minY = latToY(minLat);
+    final maxY = latToY(maxLat);
+
+    const worldSize = 2.0 * math.pi;
+    
+    final widthWorld = (maxX - minX) / worldSize;
+    final heightWorld = (maxY - minY) / worldSize;
+
+    const paddingRatio = 0.8; 
+
+    final widthZoom = math.log((containerWidth * paddingRatio) / (widthWorld * 256.0)) / math.log(2.0);
+    final heightZoom = math.log((containerHeight * paddingRatio) / (heightWorld * 256.0)) / math.log(2.0);
+
+    final optimalZoom = math.min(widthZoom, heightZoom);
+
+    return math.max(1.0, math.min(20.0, optimalZoom));
+  }
+  
+  double _calculateDistance(LatLng pos1, LatLng pos2) {
+    const earthRadius = 6371000;
+    final lat1 = pos1.latitude * math.pi / 180;
+    final lat2 = pos2.latitude * math.pi / 180;
+    final deltaLat = (pos2.latitude - pos1.latitude) * math.pi / 180;
+    final deltaLng = (pos2.longitude - pos1.longitude) * math.pi / 180;
+    
+    final a = math.sin(deltaLat / 2) * math.sin(deltaLat / 2) +
+              math.cos(lat1) * math.cos(lat2) *
+              math.sin(deltaLng / 2) * math.sin(deltaLng / 2);
+    final c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a));
+    
+    return earthRadius * c;
+  }
+
   String _getLocationInfo(TrainRecord record) {
     List<String> parts = [];
     if (record.route.isNotEmpty && record.route != "<NUL>")
@@ -276,6 +337,7 @@ class HistoryScreenState extends State<HistoryScreen> {
         .toList();
     if (positions.isEmpty) return const SizedBox.shrink();
     final bounds = LatLngBounds.fromPoints(positions);
+    final optimalZoom = _calculateOptimalZoom(positions, containerWidth: 400, containerHeight: 220);
     return Column(children: [
       const SizedBox(height: 8),
       Container(
@@ -286,10 +348,9 @@ class HistoryScreenState extends State<HistoryScreen> {
           child: FlutterMap(
               options: MapOptions(
                   initialCenter: bounds.center,
-                  initialZoom: 10,
+                  initialZoom: optimalZoom,
                   minZoom: 5,
-                  maxZoom: 18,
+                  maxZoom: 18),
-                  cameraConstraint: CameraConstraint.contain(bounds: bounds)),
               children: [
                 TileLayer(
                     urlTemplate:
@@ -495,19 +556,29 @@ class HistoryScreenState extends State<HistoryScreen> {
 
   Widget _buildExpandedContent(TrainRecord record) {
     final position = _parsePosition(record.positionInfo);
-    return Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
+    if (position == null) return const SizedBox.shrink();
-      if (position != null)
+    
-        Column(children: [
+    return FutureBuilder<double>(
+      future: Future(() => _calculateOptimalZoom([position], containerWidth: 400, containerHeight: 220)),
+      builder: (context, zoomSnapshot) {
+        if (!zoomSnapshot.hasData) {
+          return const SizedBox.shrink();
+        }
+        
+        return Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
           const SizedBox(height: 8),
           Container(
               height: 220,
+              width: double.infinity,
               margin: const EdgeInsets.symmetric(vertical: 4),
               decoration: BoxDecoration(
                   borderRadius: BorderRadius.circular(8),
                   color: Colors.grey[900]),
               child: FlutterMap(
-                  options:
+                  options: MapOptions(
-                      MapOptions(initialCenter: position, initialZoom: 15.0),
+                    initialCenter: position, 
+                    initialZoom: zoomSnapshot.data!
+                  ),
                   children: [
                     TileLayer(
                         urlTemplate:
@@ -528,8 +599,9 @@ class HistoryScreenState extends State<HistoryScreen> {
                                   color: Colors.white, size: 20)))
                     ])
                   ]))
-        ])
+        ]);
-    ]);
+      },
+    );
   }
 
   LatLng? _parsePosition(String? positionInfo) {

lib/screens/map_screen.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:flutter_map/flutter_map.dart';
 import 'package:latlong2/latlong.dart';
@@ -26,8 +27,8 @@ class _MapScreenState extends State<MapScreen> {
   bool _isMapInitialized = false;
   bool _isFollowingLocation = false;
   bool _isLocationPermissionGranted = false;
+  Timer? _locationTimer;
 
-  static const LatLng _defaultPosition = LatLng(39.9042, 116.4074);
 
   @override
   void initState() {
@@ -35,12 +36,13 @@ class _MapScreenState extends State<MapScreen> {
     _initializeMap();
     _loadTrainRecords();
     _loadSettings();
-    _requestLocationPermission();
+    _startLocationUpdates();
   }
 
   @override
   void dispose() {
     _saveSettings();
+    _locationTimer?.cancel();
     super.dispose();
   }
 
@@ -49,6 +51,9 @@ class _MapScreenState extends State<MapScreen> {
   Future<void> _requestLocationPermission() async {
     bool serviceEnabled = await Geolocator.isLocationServiceEnabled();
     if (!serviceEnabled) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('请开启定位服务')),
+      );
       return;
     }
 
@@ -58,6 +63,9 @@ class _MapScreenState extends State<MapScreen> {
     }
 
     if (permission == LocationPermission.deniedForever) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('定位权限被拒绝，请在设置中开启')),
+      );
       return;
     }
 
@@ -78,12 +86,39 @@ class _MapScreenState extends State<MapScreen> {
         _userLocation = LatLng(position.latitude, position.longitude);
       });
 
-      if (!_isMapInitialized && _userLocation != null) {
+    } catch (e) {
-        _mapController.move(_userLocation!, _currentZoom);
+    }
-      }
-    } catch (e) {}
   }
 
+  void _startLocationUpdates() {
+    _requestLocationPermission();
+    
+    _locationTimer = Timer.periodic(const Duration(seconds: 30), (timer) {
+      if (_isLocationPermissionGranted) {
+        _getCurrentLocation();
+      }
+    });
+  }
+
+  Future<void> _forceUpdateLocation() async {
+    
+    try {
+      Position position = await Geolocator.getCurrentPosition(
+        desiredAccuracy: LocationAccuracy.best,
+      );
+
+      final newLocation = LatLng(position.latitude, position.longitude);
+      
+      setState(() {
+        _userLocation = newLocation;
+      });
+
+      _mapController.move(newLocation, 15.0);
+    } catch (e) {
+    }
+  }
+
+
   Future<void> _loadSettings() async {
     try {
       final settings = await DatabaseService.instance.getAllSettings();
@@ -159,13 +194,12 @@ class _MapScreenState extends State<MapScreen> {
     } else if (_lastTrainLocation != null) {
       targetLocation = _lastTrainLocation;
     } else {
-      targetLocation = _defaultPosition;
+      _isMapInitialized = true;
+      return;
     }
 
-    WidgetsBinding.instance.addPostFrameCallback((_) {
+    _centerMap(targetLocation!, zoom: _currentZoom);
-      _centerMap(targetLocation!, zoom: _currentZoom);
+    _isMapInitialized = true;
-      _isMapInitialized = true;
-    });
   }
 
   void _centerMap(LatLng location, {double? zoom}) {
@@ -313,7 +347,7 @@ class _MapScreenState extends State<MapScreen> {
   }
 
   void _centerToMyLocation() {
-    _centerMap(_lastTrainLocation ?? _defaultPosition, zoom: 15.0);
+    _centerMap(_lastTrainLocation ?? const LatLng(39.9042, 116.4074), zoom: 15.0);
   }
 
   void _centerToLastTrain() {
@@ -537,11 +571,12 @@ class _MapScreenState extends State<MapScreen> {
           FlutterMap(
             mapController: _mapController,
             options: MapOptions(
-              initialCenter: _lastTrainLocation ?? _defaultPosition,
+              initialCenter: _lastTrainLocation ?? const LatLng(39.9042, 116.4074),
               initialZoom: _currentZoom,
               initialRotation: _currentRotation,
               minZoom: 4.0,
               maxZoom: 18.0,
+
               onPositionChanged: (MapCamera camera, bool hasGesture) {
                 if (hasGesture) {
                   setState(() {
@@ -552,28 +587,6 @@ class _MapScreenState extends State<MapScreen> {
                   _saveSettings();
                 }
               },
-              onTap: (_, point) {
-                for (final record in _trainRecords) {
-                  final coords = record.getCoordinates();
-                  final dmsCoords = _parseDmsCoordinate(record.positionInfo);
-                  LatLng? recordPosition;
-
-                  if (dmsCoords != null) {
-                    recordPosition = dmsCoords;
-                  } else if (coords['lat'] != 0.0 && coords['lng'] != 0.0) {
-                    recordPosition = LatLng(coords['lat']!, coords['lng']!);
-                  }
-
-                  if (recordPosition != null) {
-                    final distance = const Distance()
-                        .as(LengthUnit.Meter, recordPosition, point);
-                    if (distance < 50) {
-                      _showTrainDetailsDialog(record, recordPosition);
-                      break;
-                    }
-                  }
-                }
-              },
             ),
             children: [
               TileLayer(
@@ -622,10 +635,7 @@ class _MapScreenState extends State<MapScreen> {
                   heroTag: 'myLocation',
                   backgroundColor: const Color(0xFF1E1E1E),
                   onPressed: () {
-                    _getCurrentLocation();
+                    _forceUpdateLocation();
-                    if (_userLocation != null) {
-                      _centerMap(_userLocation!, zoom: 15.0);
-                    }
                   },
                   child: const Icon(Icons.my_location, color: Colors.white),
                 ),