fix MissingPluginException on unsupported platforms (#149)

Author: tlserver

lib/src/data/data_stream_factory.dart

@@ -9,6 +9,7 @@ import '../exceptions/incorrect_setup_exception.dart';
 import '../exceptions/permission_denied_exception.dart' as lm;
 import '../exceptions/permission_requesting_exception.dart' as lm;
 import '../exceptions/service_disabled_exception.dart';
+import '../exceptions/unsupported_exception.dart';
 import '../widgets/current_location_layer.dart';
 import 'data.dart';
 
@@ -63,8 +64,12 @@ class LocationMarkerDataStreamFactory {
   /// Create a heading stream which is used as default value of
   /// [CurrentLocationLayer.headingStream].
   Stream<OrientationEvent> defaultHeadingStreamSource() {
-    RotationSensor.samplingPeriod = SensorInterval.uiInterval;
-    return RotationSensor.orientationStream;
+    if (RotationSensor.isPlatformSupported) {
+      RotationSensor.samplingPeriod = SensorInterval.uiInterval;
+      return RotationSensor.orientationStream;
+    } else {
+      return Stream.error(UnsupportedException());
+    }
   }
 }
 

lib/src/exceptions/unsupported_exception.dart

@@ -0,0 +1,14 @@
+import 'package:flutter/foundation.dart';
+
+/// An exception thrown when an operation is not supported on the current
+/// platform.
+class UnsupportedException implements Exception {
+  /// Create an UnsupportedException.
+  const UnsupportedException();
+
+  @override
+  String toString() {
+    final platform = kIsWeb ? 'web' : defaultTargetPlatform.name;
+    return 'FlutterRotationSensor does not support the $platform platform.';
+  }
+}

lib/src/widgets/current_location_layer.dart

@@ -13,6 +13,7 @@ import '../exceptions/incorrect_setup_exception.dart';
 import '../exceptions/permission_denied_exception.dart';
 import '../exceptions/permission_requesting_exception.dart';
 import '../exceptions/service_disabled_exception.dart';
+import '../exceptions/unsupported_exception.dart';
 import '../options/align_on_update.dart';
 import '../options/focal_point.dart';
 import '../options/indicators.dart';
@@ -413,6 +414,10 @@ class _CurrentLocationLayerState extends State<CurrentLocationLayer>
             setState(() => _status = _Status.permissionDenied);
           case ServiceDisabledException _:
             setState(() => _status = _Status.serviceDisabled);
+          case UnsupportedException unsupportedException:
+            if (kDebugMode) {
+              print(unsupportedException);
+            }
         }
         _headingSubscription?.cancel();
       },
@@ -455,7 +460,12 @@ class _CurrentLocationLayerState extends State<CurrentLocationLayer>
           }
         }
       },
-      onError: (_) {
+      onError: (error) {
+        if (error is UnsupportedException) {
+          if (kDebugMode) {
+            print(error);
+          }
+        }
         if (_animatingHeading != null) {
           setState(() => _animatingHeading = null);
         }