Fix: This package does not work on NullSafety Project

example/android/app/build.gradle

@@ -26,7 +26,7 @@ apply plugin: 'kotlin-android'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 31
 
     sourceSets {
         main.java.srcDirs += 'src/main/kotlin'

example/lib/location_callback_handler.dart

@@ -1,7 +1,5 @@
 import 'dart:async';
-
 import 'package:background_locator/location_dto.dart';
-
 import 'location_service_repository.dart';
 
 class LocationCallbackHandler {

example/lib/location_service_repository.dart

@@ -39,25 +39,26 @@ class LocationServiceRepository {
     }
     print("$_count");
     await setLogLabel("start");
-    final SendPort send = IsolateNameServer.lookupPortByName(isolateName);
+    final SendPort? send = IsolateNameServer.lookupPortByName(isolateName);
     send?.send(null);
   }
 
   Future<void> dispose() async {
     print("***********Dispose callback handler");
     print("$_count");
     await setLogLabel("end");
-    final SendPort send = IsolateNameServer.lookupPortByName(isolateName);
+    final SendPort? send = IsolateNameServer.lookupPortByName(isolateName);
     send?.send(null);
   }
 
-  Future<void> callback(LocationDto locationDto) async {
-    print('$_count location in dart: ${locationDto.toString()}');
-    await setLogPosition(_count, locationDto);
-    final SendPort send = IsolateNameServer.lookupPortByName(isolateName);
-    send?.send(locationDto);
-    _count++;
-
+  Future<void> callback(dynamic locationDto) async {
+    if (locationDto is LocationDto) {
+      print('$_count location in dart: ${locationDto.toString()}');
+      await setLogPosition(_count, locationDto);
+      final SendPort? send = IsolateNameServer.lookupPortByName(isolateName);
+      send?.send(locationDto);
+      _count++;
+    }
   }
 
   static Future<void> setLogLabel(String label) async {
@@ -73,7 +74,7 @@ class LocationServiceRepository {
   }
 
   static double dp(double val, int places) {
-    double mod = pow(10.0, places);
+    double mod = pow(10.0, places).toDouble();
     return ((val * mod).round().toDouble() / mod);
   }
 

example/lib/main.dart

@@ -1,5 +1,4 @@
 import 'dart:async';
-import 'dart:ffi';
 import 'dart:isolate';
 import 'dart:ui';
 
@@ -9,7 +8,7 @@ import 'package:background_locator/settings/android_settings.dart';
 import 'package:background_locator/settings/ios_settings.dart';
 import 'package:background_locator/settings/locator_settings.dart';
 import 'package:flutter/material.dart';
-import 'package:location_permissions/location_permissions.dart';
+import 'package:permission_handler/permission_handler.dart';
 
 import 'file_manager.dart';
 import 'location_callback_handler.dart';
@@ -26,8 +25,8 @@ class _MyAppState extends State<MyApp> {
   ReceivePort port = ReceivePort();
 
   String logStr = '';
-  bool isRunning;
-  LocationDto lastLocation;
+  bool isRunning = false;
+  LocationDto? lastLocation;
 
   @override
   void initState() {
@@ -56,20 +55,18 @@ class _MyAppState extends State<MyApp> {
     super.dispose();
   }
 
-  Future<void> updateUI(LocationDto data) async {
+  Future<void> updateUI(LocationDto? data) async {
     final log = await FileManager.readLogFile();
 
     await _updateNotificationText(data);
 
     setState(() {
-      if (data != null) {
-        lastLocation = data;
-      }
+      lastLocation = data;
       logStr = log;
     });
   }
 
-  Future<void> _updateNotificationText(LocationDto data) async {
+  Future<void> _updateNotificationText(LocationDto? data) async {
     if (data == null) {
       return;
     }
@@ -125,12 +122,10 @@ class _MyAppState extends State<MyApp> {
       ),
     );
     String msgStatus = "-";
-    if (isRunning != null) {
-      if (isRunning) {
-        msgStatus = 'Is running';
-      } else {
-        msgStatus = 'Is not running';
-      }
+    if (isRunning) {
+      msgStatus = 'Is running';
+    } else {
+      msgStatus = 'Is not running';
     }
     final status = Text("Status: $msgStatus");
 
@@ -180,32 +175,40 @@ class _MyAppState extends State<MyApp> {
   }
 
   Future<bool> _checkLocationPermission() async {
-    final access = await LocationPermissions().checkPermissionStatus();
-    switch (access) {
-      case PermissionStatus.unknown:
-      case PermissionStatus.denied:
-      case PermissionStatus.restricted:
-        final permission = await LocationPermissions().requestPermissions(
-          permissionLevel: LocationPermissionLevel.locationAlways,
-        );
-        if (permission == PermissionStatus.granted) {
-          return true;
-        } else {
-          return false;
+    try {
+      /// Check service
+      /// Check Permission
+      PermissionStatus status = await Permission.location.status;
+      PermissionStatus statusAlways = await Permission.locationAlways.status;
+      if (statusAlways.isGranted) {
+        return true;
+      }
+      if (status.isDenied) {
+        /// Request if Denied
+        status = await Permission.location.request();
+      }
+      // At first, make request for foreground location access.
+      // And then you can request background location access.
+      if (status.isGranted) {
+        if (!statusAlways.isGranted) {
+          statusAlways = await Permission.locationAlways.request();
+          statusAlways = await Permission.locationAlways.status;
         }
-        break;
-      case PermissionStatus.granted:
+      }
+      if (statusAlways.isGranted) {
         return true;
-        break;
-      default:
+      } else {
         return false;
-        break;
+      }
+    } catch (e) {
+      return false;
     }
   }
 
-  Future<void> _startLocator() async{
+  Future<void> _startLocator() async {
     Map<String, dynamic> data = {'countInit': 1};
-    return await BackgroundLocator.registerLocationUpdate(LocationCallbackHandler.callback,
+    return await BackgroundLocator.registerLocationUpdate(
+        LocationCallbackHandler.callback,
         initCallback: LocationCallbackHandler.initCallback,
         initDataCallback: data,
         disposeCallback: LocationCallbackHandler.disposeCallback,

example/pubspec.yaml

@@ -3,7 +3,7 @@ description: Demonstrates how to use the background_locator plugin.
 publish_to: 'none'
 
 environment:
-  sdk: ">=2.8.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter:
@@ -21,7 +21,7 @@ dev_dependencies:
     path: ../
 
   path_provider: ^2.0.8
-  location_permissions: ^3.0.0+1
+  permission_handler: ^9.1.0
 
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec

example/test/widget_test.dart

@@ -1,26 +1 @@
-// This is a basic Flutter widget test.
-//
-// To perform an interaction with a widget in your test, use the WidgetTester
-// utility that Flutter provides. For example, you can send tap and scroll
-// gestures. You can also use WidgetTester to find child widgets in the widget
-// tree, read text, and verify that the values of widget properties are correct.
 
-import 'package:background_locator_example/main.dart';
-import 'package:flutter/material.dart';
-import 'package:flutter_test/flutter_test.dart';
-
-void main() {
-  testWidgets('Verify Platform version', (WidgetTester tester) async {
-    // Build our app and trigger a frame.
-    await tester.pumpWidget(MyApp());
-
-    // Verify that platform version is retrieved.
-    expect(
-      find.byWidgetPredicate(
-        (Widget widget) =>
-            widget is Text && widget.data.startsWith('Running on:'),
-      ),
-      findsOneWidget,
-    );
-  });
-}

lib/location_dto.dart

@@ -40,7 +40,7 @@ class LocationDto {
       json[Keys.ARG_HEADING],
       json[Keys.ARG_TIME],
       isLocationMocked,
-      json[Keys.ARG_PROVIDER],
+      json[Keys.ARG_PROVIDER] ?? '',
     );
   }