Add support for restoring after app kill in iOS

Author: NicolaVerbeeck

CHANGELOG.md

@@ -1,7 +1,8 @@
-## 1.1.0 - 14-10-2021
+## 1.1.0 - xx-xx-2021
 #Added
 - Added more options to android config to specify update interval
 - Added iOS specific options to control activity type and/or distance filter
+- Added iOS specific options to restart the tracking after killing the app
 - Added option to Android specific options to only get updates every x meters
 
 ## 1.0.2 - 22-06-2021

example/lib/main.dart

@@ -16,6 +16,7 @@ Future<void> main() async {
   await BackgroundLocationTrackerManager.initialize(
     _backgroundCallback,
     config: const BackgroundLocationTrackerConfig(
+      loggingEnabled: true,
       androidConfig: AndroidConfig(
         notificationIcon: 'explore',
         trackingInterval: Duration(seconds: 4),
@@ -24,6 +25,7 @@ Future<void> main() async {
       iOSConfig: IOSConfig(
         activityType: ActivityType.FITNESS,
         distanceFilterMeters: 5,
+        restartAfterKill: true,
       ),
     ),
   );

ios/Classes/ForegroundChannel.swift

@@ -51,6 +51,7 @@ public class ForegroundChannel : NSObject {
         let loggingEnabledKey = "logging_enabled"
         let activityTypeKey = "ios_activity_type"
         let distanceFilterKey = "ios_distance_filter"
+        let restartAfterKillKey = "ios_restart_after_kill"
         let map = call.arguments as? [String: Any]
         guard let callbackDispatcherHandle = map?[callBackHandleKey] else {
             result(false)
@@ -60,6 +61,7 @@ public class ForegroundChannel : NSObject {
 
         let loggingEnabled: Bool = map?[loggingEnabledKey] as? Bool ?? false
         SharedPrefsUtil.saveLoggingEnabled(loggingEnabled)
+        SharedPrefsUtil.saveRestartAfterKillEnabled(map?[restartAfterKillKey] as? Bool ?? false)
 
         let activityType: CLActivityType
         switch (map?[activityTypeKey] as? String ?? "AUTOMOTIVE") {

ios/Classes/SharedPrefsUtil.swift

@@ -12,6 +12,7 @@ struct SharedPrefsUtil {
 
     private static let KEY_CALLBACK_HANDLER = "background.location.tracker.manager.CALLBACK_DISPATCHER_HANDLE_KEY"
     private static let KEY_IS_TRACKING = "background.location.tracker.manager.IS_TRACKING"
+    private static let KEY_IS_RESTART_AFTER_KILL = "background.location.tracker.manager.RESTART_AFTER_KILL"
     private static let KEY_LOGGING_ENABLED = "background.location.tracker.manager.LOGGIN_ENABLED"
     private static let KEY_DISTANCE_FILTER = "background.location.tracker.manager.DISTANCE_FILTER"
     private static let KEY_ACTIVITY_TYPE = "background.location.tracker.manager.KEY_ACTIVITY_TYPE"
@@ -38,6 +39,14 @@ struct SharedPrefsUtil {
         return getValue(for: SharedPrefsUtil.KEY_IS_TRACKING) ?? false
     }
 
+    static func restartAfterKill() -> Bool {
+        return getValue(for: SharedPrefsUtil.KEY_IS_RESTART_AFTER_KILL) ?? false
+    }
+    
+    static func saveRestartAfterKillEnabled(_ isRestartEnabled: Bool) {
+        store(isRestartEnabled, key: SharedPrefsUtil.KEY_IS_RESTART_AFTER_KILL)
+    }
+    
     static func saveLoggingEnabled(_ isLoggingEnabled: Bool) {
         store(isLoggingEnabled, key: SharedPrefsUtil.KEY_LOGGING_ENABLED)
     }

ios/Classes/SwiftBackgroundLocationTrackerPlugin.swift

@@ -36,6 +36,11 @@ extension SwiftBackgroundLocationTrackerPlugin: FlutterPlugin {
         let instance = SwiftBackgroundLocationTrackerPlugin()
         registrar.addMethodCallDelegate(instance, channel: methodChannel)
         registrar.addApplicationDelegate(instance)
+        
+        if (SharedPrefsUtil.isTracking() && SharedPrefsUtil.restartAfterKill()) {
+            instance.locationManager.delegate = instance
+            instance.locationManager.startUpdatingLocation()
+        }
     }
 
     public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {

lib/src/channel/foreground_channel.dart

@@ -41,6 +41,7 @@ class ForegroundChannel {
         'android_distance_filter': config.androidConfig.distanceFilterMeters,
         'ios_activity_type': _activityTypeString(config.iOSConfig.activityType),
         'ios_distance_filter': config.iOSConfig.distanceFilterMeters,
+        'ios_restart_after_kill': config.iOSConfig.restartAfterKill,
       },
     );
   }

lib/src/model/config/ios_config.dart

@@ -10,13 +10,18 @@ class IOSConfig {
   /// The type of activity, default to [ActivityType.AUTOMOTIVE]
   final ActivityType activityType;
 
+  /// Restart the location tracker when the app is recreated
+  /// after it has been killed by the user. Defaults to false
+  final bool restartAfterKill;
+
   /// The distance in meters that should be moved before updates are sent.
   /// Defaults to no filter (null)
   final int? distanceFilterMeters;
 
   const IOSConfig({
     this.activityType = ActivityType.AUTOMOTIVE,
     this.distanceFilterMeters,
+    this.restartAfterKill = false,
   });
 }