sqllite database save magnetic declination data

lib/states/region.dart

@@ -1,7 +1,13 @@
 import 'dart:convert';
+import 'dart:io';
 
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_pickers/address_picker/locations_data.dart';
+import 'package:path/path.dart';
 import 'package:shared_preferences/shared_preferences.dart';
+import 'package:sqflite/sqflite.dart';
 
 import '../models/region.dart';
 
@@ -14,6 +20,10 @@ class RegionProvider extends ChangeNotifier {
   String _cityName = '';
   String _tempProvinceName = '';
   String _tempCityName = '';
+  double _declination = 0.0;
+  double _tempDeclination = 0.0;
+
+  Database db;
 
   String get provinceName => _provinceName;
 
@@ -23,39 +33,93 @@ class RegionProvider extends ChangeNotifier {
 
   String get tempCityName => _tempCityName;
 
+  double get tempDeclination => _tempDeclination;
+
+  double get declination => _declination;
+
   final Future<SharedPreferences> _prefs = SharedPreferences.getInstance();
 
-  loadRegionData() {
-    _prefs.then((prefs) {
-      if (prefs.getString('REGION') != null) {
-        final region =
-            RegionData.fromJson(jsonDecode(prefs.getString('REGION')));
-        _provinceName = region.provinceName;
-        _cityName = region.cityName;
-        _tempProvinceName = region.provinceName;
-        _tempCityName = region.cityName;
-        notifyListeners();
+  loadRegionData() async {
+    db = await loadDatabase();
+    final prefs = await _prefs;
+    if (prefs.getString('REGION') != null) {
+      final region = RegionData.fromJson(jsonDecode(prefs.getString('REGION')));
+      _provinceName = region.provinceName;
+      _cityName = region.cityName;
+      _tempProvinceName = region.provinceName;
+      _tempCityName = region.cityName;
+      // WidgetsFlutterBinding.ensureInitialized();
+      List<String> cityCode = Address.getCityCodeByName(
+          provinceName: _provinceName, cityName: _cityName);
+      if (cityCode.length == 2) {
+        List<Map<String, Object>> decMap = await db.rawQuery(
+            "SELECT declination FROM magnetic_declination WHERE cityId == ${cityCode[1]}");
+        _declination = decMap[0]['declination'];
+        _tempDeclination = decMap[0]['declination'];
+      } else {
+        _declination = 0.0;
+        _tempDeclination = 0.0;
       }
-    });
+
+      notifyListeners();
+    }
   }
 
-  updateRegion(pname, cname) {
-    // _provinceName = pname;
-    // _cityName = cname;
+  Future<Database> loadDatabase() async {
+    var databasesPath = await getDatabasesPath();
+    var path = join(databasesPath, "magnetic_declination.db");
+    var exists = await databaseExists(path);
+    if (!exists) {
+      print("Creating new copy from asset");
+      try {
+        await Directory(dirname(path)).create(recursive: true);
+      } catch (_) {}
+      // Copy from asset
+      ByteData data =
+          await rootBundle.load(join("assets", "magnetic_declination.db"));
+      List<int> bytes =
+          data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
+      // Write and flush the bytes written
+      await File(path).writeAsBytes(bytes, flush: true);
+    } else {
+      print("Opening existing database");
+    }
+// open the database
+    Database _db = await openDatabase(path, readOnly: true);
+    return _db;
+  }
+
+  // 存储临时的省市名称，不会保存本地
+  void updateRegion(pname, cname) async {
     _tempProvinceName = pname;
     _tempCityName = cname;
-
+    List<String> cityCode = Address.getCityCodeByName(
+        provinceName: _tempProvinceName, cityName: _tempCityName);
+    print(cityCode);
+    if (cityCode.length == 2) {
+      List<Map<String, Object>> decMap = await db.rawQuery(
+          "SELECT declination FROM magnetic_declination WHERE cityId == ${cityCode[1]}");
+      print(decMap);
+      _tempDeclination = decMap[0]['declination'];
+    } else {
+      _tempDeclination = 0.0;
+    }
     notifyListeners();
   }
 
+  //更新磁偏角
+  void updateDeclination(pname, cname) {}
+
   //将临时变量保存到正式变量，并保存本地
-  saveRegion() {
+  void saveRegion() {
     _provinceName = _tempProvinceName;
     _cityName = _tempCityName;
+    _declination = _tempDeclination;
     print(_tempCityName);
     final region = <String, dynamic>{
       "provinceName": _tempProvinceName,
-      'cityName': _tempCityName
+      'cityName': _tempCityName,
+      // 'declination': _tempDeclination
     };
     _prefs.then((prefs) {
       prefs.setString('REGION', jsonEncode(region));
@@ -64,16 +128,18 @@ class RegionProvider extends ChangeNotifier {
   }
 
   // 覆盖临时的变量
-  resetTemp() async {
+  void resetTemp() async {
     _tempProvinceName = _provinceName;
     _tempCityName = _cityName;
+    _tempDeclination = _declination;
     notifyListeners();
   }
 
   // 将临时的省市名设为空
-  clearTemp() {
+  void clearTemp() {
     _tempProvinceName = '';
     _tempCityName = '';
+    _tempDeclination = 0.0;
     notifyListeners();
   }
 }

lib/states/token.dart

@@ -12,7 +12,7 @@ class TokenProvider extends ChangeNotifier {
 
   bool get isLogin => _loginBean != null;
 
-  loadToken() {
+  void loadToken() {
     Map<String, dynamic> map = SPUtil.getObject("token_bean");
     if (map != null) {
       //加载缓存
@@ -21,13 +21,15 @@ class TokenProvider extends ChangeNotifier {
     notifyListeners();
   }
 
-  clearToken() {
+  void clearToken() {
     _loginBean = null;
+    SPUtil.remove("token_bean");
     notifyListeners();
   }
 
-  setToken(LoginBean lb) {
+  void setToken(LoginBean lb) {
     _loginBean = lb;
+    SPUtil.saveObject("token_bean", lb);
     notifyListeners();
   }
 }