diff --git a/example/lib/base_map.dart b/example/lib/base_map.dart
index 17d7162..4301205 100644
--- a/example/lib/base_map.dart
+++ b/example/lib/base_map.dart
@@ -89,10 +89,10 @@ class _BaseMapPageState extends State<BaseMapPage> {
     ));
   }
 
-  _onSymbolTap(LatLng position, String caption) {
+  _onSymbolTap(LatLng? position, String? caption) {
     ScaffoldMessenger.of(context).showSnackBar(SnackBar(
       content: Text(
-          '[onSymbolTap] caption: $caption, lat: ${position.latitude}, lon: ${position.longitude}'),
+          '[onSymbolTap] caption: $caption, lat: ${position?.latitude}, lon: ${position?.longitude}'),
       duration: Duration(milliseconds: 500),
       backgroundColor: Colors.black,
     ));
@@ -203,8 +203,8 @@ class _BaseMapPageState extends State<BaseMapPage> {
   // }
 
   void _onCameraChange(
-      LatLng latLng, CameraChangeReason reason, bool isAnimated) {
-    print('카메라 움직임 >>> 위치 : ${latLng.latitude}, ${latLng.longitude}'
+      LatLng? latLng, CameraChangeReason reason, bool? isAnimated) {
+    print('카메라 움직임 >>> 위치 : ${latLng?.latitude}, ${latLng?.longitude}'
         '\n원인: $reason'
         '\n에니메이션 여부: $isAnimated');
   }
diff --git a/example/lib/circle_map.dart b/example/lib/circle_map.dart
index c3d8981..6f5120c 100644
--- a/example/lib/circle_map.dart
+++ b/example/lib/circle_map.dart
@@ -14,7 +14,7 @@ class _CircleMapPageState extends State<CircleMapPage> {
   List<CircleOverlay> _circles = [];
   double _sliderValue = 40.0;
 
-  int _selectedCircleIndex;
+  late int _selectedCircleIndex;
 
   @override
   Widget build(BuildContext context) {
diff --git a/example/lib/marker_map_page.dart b/example/lib/marker_map_page.dart
index 58c709b..dcff60e 100644
--- a/example/lib/marker_map_page.dart
+++ b/example/lib/marker_map_page.dart
@@ -19,7 +19,7 @@ class _MarkerMapPageState extends State<MarkerMapPage> {
 
   @override
   void initState() {
-    WidgetsBinding.instance.addPostFrameCallback((_) {
+    WidgetsBinding.instance!.addPostFrameCallback((_) {
       OverlayImage.fromAssetImage(
         assetName: 'icon/marker.png',
       ).then((image) {
@@ -173,14 +173,14 @@ class _MarkerMapPageState extends State<MarkerMapPage> {
     }
   }
 
-  void _onMarkerTap(Marker marker, Map<String, int> iconSize) {
-    int pos = _markers.indexWhere((m) => m.markerId == marker.markerId);
+  void _onMarkerTap(Marker? marker, Map<String, int?> iconSize) {
+    int pos = _markers.indexWhere((m) => m.markerId == marker?.markerId);
     setState(() {
       _markers[pos].captionText = '선택됨';
     });
     if (_currentMode == MODE_REMOVE) {
       setState(() {
-        _markers.removeWhere((m) => m.markerId == marker.markerId);
+        _markers.removeWhere((m) => m.markerId == marker?.markerId);
       });
     }
   }
diff --git a/example/lib/path_map.dart b/example/lib/path_map.dart
index 5fce3a0..b087fca 100644
--- a/example/lib/path_map.dart
+++ b/example/lib/path_map.dart
@@ -196,11 +196,11 @@ class _PathMapPageState extends State<PathMapPage> {
     }
   }
 
-  void _onMarkerTap(Marker marker, Map<String, int> iconSize) {
+  void _onMarkerTap(Marker? marker, Map<String, int?> iconSize) {
     if (_currentMode == MODE_REMOVE && _coordinates.length > 2) {
       setState(() {
-        _coordinates.remove(marker.position);
-        _markers.removeWhere((m) => m.markerId == marker.markerId);
+        _coordinates.remove(marker?.position);
+        _markers.removeWhere((m) => m.markerId == marker?.markerId);
       });
     }
   }
diff --git a/example/lib/polygon_map.dart b/example/lib/polygon_map.dart
index 978e411..b825f72 100644
--- a/example/lib/polygon_map.dart
+++ b/example/lib/polygon_map.dart
@@ -13,9 +13,9 @@ class _PolygonMapState extends State<PolygonMap>
   bool _isAdding = false;
 
   Completer<NaverMapController> _controller = Completer();
-  AnimationController _animationController;
-  Animation _colorTwin;
-  Animation _rotation;
+  late AnimationController _animationController;
+  late Animation _colorTwin;
+  late Animation<double> _rotation;
 
   List<Marker> _markers = [];
   List<PolygonOverlay> _polygon = [];
@@ -165,7 +165,7 @@ class _PolygonMapState extends State<PolygonMap>
       if (_markers.length >= 3) {
         _polygon.add(PolygonOverlay(
           DateTime.now().millisecondsSinceEpoch.toString(),
-          _markers.map((e) => e.position).toList(),
+          _markers.map((e) => e.position!).toList(),
           color: Colors.transparent,
           outlineWidth: 3,
           outlineColor: Colors.redAccent,
diff --git a/example/lib/text_field_page.dart b/example/lib/text_field_page.dart
index 9b638ea..b49282b 100644
--- a/example/lib/text_field_page.dart
+++ b/example/lib/text_field_page.dart
@@ -22,26 +22,26 @@ class _TextFieldPageState extends State<TextFieldPage> {
   }
 
   _mapView() => NaverMap(
-    useSurface: kReleaseMode,
-    initLocationTrackingMode: LocationTrackingMode.Follow,
-  );
+        useSurface: kReleaseMode,
+        initLocationTrackingMode: LocationTrackingMode.Follow,
+      );
 
   _textFieldView() => Align(
-    alignment: Alignment.topCenter,
-    child: SafeArea(
-      bottom: false,
-      child: Container(
-        decoration: BoxDecoration(
-          color: Colors.white,
-          borderRadius: BorderRadius.circular(50),
+        alignment: Alignment.topCenter,
+        child: SafeArea(
+          bottom: false,
+          child: Container(
+            decoration: BoxDecoration(
+              color: Colors.white,
+              borderRadius: BorderRadius.circular(50),
+            ),
+            margin: EdgeInsets.all(24),
+            padding: EdgeInsets.symmetric(horizontal: 24, vertical: 8),
+            child: TextField(
+              decoration: InputDecoration.collapsed(hintText: ''),
+              maxLines: 1,
+            ),
+          ),
         ),
-        margin: EdgeInsets.all(24),
-        padding: EdgeInsets.symmetric(horizontal: 24, vertical: 8),
-        child: TextField(
-          decoration: InputDecoration.collapsed(hintText: ''),
-          maxLines: 1,
-        ),
-      ),
-    ),
-  );
+      );
 }