[Activity Recognition] Fix NullPointerException in the Android plugin

packages/activity_recognition_flutter/android/src/main/java/dk/cachet/activity_recognition_flutter/ActivityRecognitionFlutterPlugin.java

@@ -108,7 +108,7 @@ void startForegroundService() {
         // Pass the notification title/text/icon to the service
         intent.putExtra("title", "MonsensoMonitor")
                 .putExtra("text", "Monsenso Foreground Service")
-                .putExtra("icon", R.drawable.common_full_open_on_phone)
+                .putExtra("icon", android.R.drawable.ic_dialog_info)
                 .putExtra("importance", 3)
                 .putExtra("id", 10);
 
@@ -168,7 +168,7 @@ public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, Strin
         // Log.d("onSharedPreferenceChange", result);
         if (key!= null && key.equals(DETECTED_ACTIVITY)) {
             // Log.d(TAG, "Detected activity: " + result);
-            eventSink.success(result);
+            if (eventSink != null) eventSink.success(result);
         }
     }
   }

packages/activity_recognition_flutter/android/src/main/java/dk/cachet/activity_recognition_flutter/ActivityRecognizedService.java

@@ -33,7 +33,10 @@ protected void onHandleWork(@Nullable Intent intent) {
     // remove override and make onHandleIntent private.
     private void onHandleIntent(@Nullable Intent intent) {
         ActivityRecognitionResult result = ActivityRecognitionResult.extractResult(intent);
+        if (result == null) return;
+
         List<DetectedActivity> activities = result.getProbableActivities();
+        if (activities == null || activities.isEmpty()) return;
 
         DetectedActivity mostLikely = activities.get(0);
 
@@ -54,6 +57,7 @@ private void onHandleIntent(@Nullable Intent intent) {
         SharedPreferences preferences =
                 getApplicationContext().getSharedPreferences(
                         ActivityRecognitionFlutterPlugin.ACTIVITY_RECOGNITION, MODE_PRIVATE);
+        if (preferences == null) return;
 
         preferences.edit().clear()
                 .putString(

packages/activity_recognition_flutter/android/src/main/java/dk/cachet/activity_recognition_flutter/ForegroundService.java

@@ -66,7 +66,7 @@ private void startPluginForegroundService(Bundle extras) {
 
         // Get notification icon
 //        int icon = getResources().getIdentifier((String) extras.get("icon"), "drawable", context.getPackageName());
-        int icon = R.drawable.common_full_open_on_phone;
+        int icon = android.R.drawable.ic_dialog_info;
 
         // Make notification
         Notification notification = new Notification.Builder(context, "foreground.service.channel")

packages/activity_recognition_flutter/example/android/gradle.properties

@@ -1,4 +1,3 @@
 org.gradle.jvmargs=-Xmx1536M
 android.useAndroidX=true
 android.enableJetifier=true
-android.enableR8=true

packages/activity_recognition_flutter/example/pubspec.yaml

@@ -28,7 +28,7 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  permission_handler: ^7.0.0
+  permission_handler: 11.3.1
 
 flutter:
   uses-material-design: true