diff --git a/.github/workflows/analyze.yml b/.github/workflows/analyze.yml
index 8508bd3bf..5d09a9f88 100644
--- a/.github/workflows/analyze.yml
+++ b/.github/workflows/analyze.yml
@@ -9,7 +9,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: subosito/flutter-action@v1
         with:
-          flutter-version: "2.2.1"
+          flutter-version: "2.5.1"
       - name: Install pub dependencies
         run: |
           for d in `pwd`/packages/*/; do
diff --git a/packages/webview_flutter/CHANGELOG.md b/packages/webview_flutter/CHANGELOG.md
index ed67c1134..add91cc14 100644
--- a/packages/webview_flutter/CHANGELOG.md
+++ b/packages/webview_flutter/CHANGELOG.md
@@ -40,4 +40,7 @@
 
 ## 0.3.6
 * Update LWE binary (3dff8724bfb4b2b0b9e7c4e3976a9b02e74ee13c)
-* Fix various issue
\ No newline at end of file
+* Fix various issue
+
+## 0.3.7
+* Update webivew_flutter to 2.1.1
\ No newline at end of file
diff --git a/packages/webview_flutter/README.md b/packages/webview_flutter/README.md
index ff3201454..ab2a59da1 100644
--- a/packages/webview_flutter/README.md
+++ b/packages/webview_flutter/README.md
@@ -22,7 +22,7 @@ This package is not an _endorsed_ implementation of `webview_flutter`. Therefore
 
 ```yaml
 dependencies:
-  webview_flutter_tizen: ^0.3.5
+  webview_flutter_tizen: ^0.3.7
 ```
 
 ## Example
diff --git a/packages/webview_flutter/example/integration_test/webview_flutter_test.dart b/packages/webview_flutter/example/integration_test/webview_flutter_test.dart
index f454c92b4..dc782c3dc 100644
--- a/packages/webview_flutter/example/integration_test/webview_flutter_test.dart
+++ b/packages/webview_flutter/example/integration_test/webview_flutter_test.dart
@@ -1,9 +1,7 @@
-// Copyright 2018 The Chromium Authors. All rights reserved.
+// Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.9
-
 import 'dart:math';
 import 'dart:typed_data';
 
@@ -12,15 +10,14 @@ import 'package:flutter/src/foundation/basic_types.dart';
 import 'package:flutter/src/gestures/recognizer.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:webview_flutter/platform_interface.dart';
+import 'package:webview_flutter_platform_interface/webview_flutter_platform_interface.dart';
 import 'package:webview_flutter/webview_flutter.dart';
 import 'package:webview_flutter_tizen/webview_flutter_tizen.dart';
-import 'package:integration_test/integration_test.dart';
 
 typedef void VoidCallback();
 
 void main() {
-  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+  TestWidgetsFlutterBinding.ensureInitialized();
 
   final _FakePlatformViewsController fakePlatformViewsController =
       _FakePlatformViewsController();
@@ -45,7 +42,7 @@ void main() {
   });
 
   testWidgets('Initial url', (WidgetTester tester) async {
-    WebViewController controller;
+    late WebViewController controller;
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://youtube.com',
@@ -65,7 +62,7 @@ void main() {
     ));
 
     final FakePlatformWebView platformWebView =
-        fakePlatformViewsController.lastCreatedView;
+        fakePlatformViewsController.lastCreatedView!;
 
     expect(platformWebView.javascriptMode, JavascriptMode.unrestricted);
 
@@ -77,7 +74,7 @@ void main() {
   });
 
   testWidgets('Load url', (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         onWebViewCreated: (WebViewController webViewController) {
@@ -88,13 +85,13 @@ void main() {
 
     expect(controller, isNotNull);
 
-    await controller.loadUrl('https://flutter.io');
+    await controller!.loadUrl('https://flutter.io');
 
-    expect(await controller.currentUrl(), 'https://flutter.io');
+    expect(await controller!.currentUrl(), 'https://flutter.io');
   });
 
   testWidgets('Invalid urls', (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         onWebViewCreated: (WebViewController webViewController) {
@@ -105,19 +102,18 @@ void main() {
 
     expect(controller, isNotNull);
 
-    expect(() => controller.loadUrl(null), throwsA(anything));
-    expect(await controller.currentUrl(), isNull);
+    expect(await controller!.currentUrl(), isNull);
 
-    expect(() => controller.loadUrl(''), throwsA(anything));
-    expect(await controller.currentUrl(), isNull);
+    expect(() => controller!.loadUrl(''), throwsA(anything));
+    expect(await controller!.currentUrl(), isNull);
 
     // Missing schema.
-    expect(() => controller.loadUrl('flutter.io'), throwsA(anything));
-    expect(await controller.currentUrl(), isNull);
+    expect(() => controller!.loadUrl('flutter.io'), throwsA(anything));
+    expect(await controller!.currentUrl(), isNull);
   });
 
   testWidgets('Headers in loadUrl', (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         onWebViewCreated: (WebViewController webViewController) {
@@ -131,13 +127,13 @@ void main() {
     final Map<String, String> headers = <String, String>{
       'CACHE-CONTROL': 'ABC'
     };
-    await controller.loadUrl('https://flutter.io', headers: headers);
-    expect(await controller.currentUrl(), equals('https://flutter.io'));
+    await controller!.loadUrl('https://flutter.io', headers: headers);
+    expect(await controller!.currentUrl(), equals('https://flutter.io'));
   });
 
   testWidgets("Can't go back before loading a page",
       (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         onWebViewCreated: (WebViewController webViewController) {
@@ -148,13 +144,13 @@ void main() {
 
     expect(controller, isNotNull);
 
-    final bool canGoBackNoPageLoaded = await controller.canGoBack();
+    final bool canGoBackNoPageLoaded = await controller!.canGoBack();
 
     expect(canGoBackNoPageLoaded, false);
   });
 
   testWidgets("Clear Cache", (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         onWebViewCreated: (WebViewController webViewController) {
@@ -164,15 +160,15 @@ void main() {
     );
 
     expect(controller, isNotNull);
-    expect(fakePlatformViewsController.lastCreatedView.hasCache, true);
+    expect(fakePlatformViewsController.lastCreatedView!.hasCache, true);
 
-    await controller.clearCache();
+    await controller!.clearCache();
 
-    expect(fakePlatformViewsController.lastCreatedView.hasCache, false);
+    expect(fakePlatformViewsController.lastCreatedView!.hasCache, false);
   });
 
   testWidgets("Can't go back with no history", (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://flutter.io',
@@ -183,13 +179,13 @@ void main() {
     );
 
     expect(controller, isNotNull);
-    final bool canGoBackFirstPageLoaded = await controller.canGoBack();
+    final bool canGoBackFirstPageLoaded = await controller!.canGoBack();
 
     expect(canGoBackFirstPageLoaded, false);
   });
 
   testWidgets('Can go back', (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://flutter.io',
@@ -201,15 +197,15 @@ void main() {
 
     expect(controller, isNotNull);
 
-    await controller.loadUrl('https://www.google.com');
-    final bool canGoBackSecondPageLoaded = await controller.canGoBack();
+    await controller!.loadUrl('https://www.google.com');
+    final bool canGoBackSecondPageLoaded = await controller!.canGoBack();
 
     expect(canGoBackSecondPageLoaded, true);
   });
 
   testWidgets("Can't go forward before loading a page",
       (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         onWebViewCreated: (WebViewController webViewController) {
@@ -220,13 +216,13 @@ void main() {
 
     expect(controller, isNotNull);
 
-    final bool canGoForwardNoPageLoaded = await controller.canGoForward();
+    final bool canGoForwardNoPageLoaded = await controller!.canGoForward();
 
     expect(canGoForwardNoPageLoaded, false);
   });
 
   testWidgets("Can't go forward with no history", (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://flutter.io',
@@ -237,13 +233,13 @@ void main() {
     );
 
     expect(controller, isNotNull);
-    final bool canGoForwardFirstPageLoaded = await controller.canGoForward();
+    final bool canGoForwardFirstPageLoaded = await controller!.canGoForward();
 
     expect(canGoForwardFirstPageLoaded, false);
   });
 
   testWidgets('Can go forward', (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://flutter.io',
@@ -255,15 +251,15 @@ void main() {
 
     expect(controller, isNotNull);
 
-    await controller.loadUrl('https://youtube.com');
-    await controller.goBack();
-    final bool canGoForwardFirstPageBacked = await controller.canGoForward();
+    await controller!.loadUrl('https://youtube.com');
+    await controller!.goBack();
+    final bool canGoForwardFirstPageBacked = await controller!.canGoForward();
 
     expect(canGoForwardFirstPageBacked, true);
   });
 
   testWidgets('Go back', (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://youtube.com',
@@ -275,19 +271,19 @@ void main() {
 
     expect(controller, isNotNull);
 
-    expect(await controller.currentUrl(), 'https://youtube.com');
+    expect(await controller!.currentUrl(), 'https://youtube.com');
 
-    await controller.loadUrl('https://flutter.io');
+    await controller!.loadUrl('https://flutter.io');
 
-    expect(await controller.currentUrl(), 'https://flutter.io');
+    expect(await controller!.currentUrl(), 'https://flutter.io');
 
-    await controller.goBack();
+    await controller!.goBack();
 
-    expect(await controller.currentUrl(), 'https://youtube.com');
+    expect(await controller!.currentUrl(), 'https://youtube.com');
   });
 
   testWidgets('Go forward', (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://youtube.com',
@@ -299,23 +295,23 @@ void main() {
 
     expect(controller, isNotNull);
 
-    expect(await controller.currentUrl(), 'https://youtube.com');
+    expect(await controller!.currentUrl(), 'https://youtube.com');
 
-    await controller.loadUrl('https://flutter.io');
+    await controller!.loadUrl('https://flutter.io');
 
-    expect(await controller.currentUrl(), 'https://flutter.io');
+    expect(await controller!.currentUrl(), 'https://flutter.io');
 
-    await controller.goBack();
+    await controller!.goBack();
 
-    expect(await controller.currentUrl(), 'https://youtube.com');
+    expect(await controller!.currentUrl(), 'https://youtube.com');
 
-    await controller.goForward();
+    await controller!.goForward();
 
-    expect(await controller.currentUrl(), 'https://flutter.io');
+    expect(await controller!.currentUrl(), 'https://flutter.io');
   });
 
   testWidgets('Current URL', (WidgetTester tester) async {
-    WebViewController controller;
+    WebViewController? controller;
     await tester.pumpWidget(
       WebView(
         onWebViewCreated: (WebViewController webViewController) {
@@ -327,20 +323,20 @@ void main() {
     expect(controller, isNotNull);
 
     // Test a WebView without an explicitly set first URL.
-    expect(await controller.currentUrl(), isNull);
+    expect(await controller!.currentUrl(), isNull);
 
-    await controller.loadUrl('https://youtube.com');
-    expect(await controller.currentUrl(), 'https://youtube.com');
+    await controller!.loadUrl('https://youtube.com');
+    expect(await controller!.currentUrl(), 'https://youtube.com');
 
-    await controller.loadUrl('https://flutter.io');
-    expect(await controller.currentUrl(), 'https://flutter.io');
+    await controller!.loadUrl('https://flutter.io');
+    expect(await controller!.currentUrl(), 'https://flutter.io');
 
-    await controller.goBack();
-    expect(await controller.currentUrl(), 'https://youtube.com');
+    await controller!.goBack();
+    expect(await controller!.currentUrl(), 'https://youtube.com');
   });
 
   testWidgets('Reload url', (WidgetTester tester) async {
-    WebViewController controller;
+    late WebViewController controller;
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://flutter.io',
@@ -351,7 +347,7 @@ void main() {
     );
 
     final FakePlatformWebView platformWebView =
-        fakePlatformViewsController.lastCreatedView;
+        fakePlatformViewsController.lastCreatedView!;
 
     expect(platformWebView.currentUrl, 'https://flutter.io');
     expect(platformWebView.amountOfReloadsOnCurrentUrl, 0);
@@ -367,7 +363,7 @@ void main() {
   });
 
   testWidgets('evaluate Javascript', (WidgetTester tester) async {
-    WebViewController controller;
+    late WebViewController controller;
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://flutter.io',
@@ -380,15 +376,11 @@ void main() {
     expect(
         await controller.evaluateJavascript("fake js string"), "fake js string",
         reason: 'should get the argument');
-    expect(
-      () => controller.evaluateJavascript(null),
-      throwsA(anything),
-    );
   });
 
   testWidgets('evaluate Javascript with JavascriptMode disabled',
       (WidgetTester tester) async {
-    WebViewController controller;
+    late WebViewController controller;
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://flutter.io',
@@ -402,10 +394,6 @@ void main() {
       () => controller.evaluateJavascript('fake js string'),
       throwsA(anything),
     );
-    expect(
-      () => controller.evaluateJavascript(null),
-      throwsA(anything),
-    );
   });
 
   testWidgets('Cookies can be cleared once', (WidgetTester tester) async {
@@ -437,19 +425,17 @@ void main() {
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://youtube.com',
-        // TODO(iskakaushik): Remove this when collection literals makes it to stable.
-        // ignore: prefer_collection_literals
-        javascriptChannels: <JavascriptChannel>[
+        javascriptChannels: <JavascriptChannel>{
           JavascriptChannel(
               name: 'Tts', onMessageReceived: (JavascriptMessage msg) {}),
           JavascriptChannel(
               name: 'Alarm', onMessageReceived: (JavascriptMessage msg) {}),
-        ].toSet(),
+        },
       ),
     );
 
     final FakePlatformWebView platformWebView =
-        fakePlatformViewsController.lastCreatedView;
+        fakePlatformViewsController.lastCreatedView!;
 
     expect(platformWebView.javascriptChannelNames,
         unorderedEquals(<String>['Tts', 'Alarm']));
@@ -477,14 +463,12 @@ void main() {
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://youtube.com',
-        // TODO(iskakaushik): Remove this when collection literals makes it to stable.
-        // ignore: prefer_collection_literals
-        javascriptChannels: <JavascriptChannel>[
+        javascriptChannels: <JavascriptChannel>{
           JavascriptChannel(
               name: 'Alarm', onMessageReceived: (JavascriptMessage msg) {}),
           JavascriptChannel(
               name: 'Alarm', onMessageReceived: (JavascriptMessage msg) {}),
-        ].toSet(),
+        },
       ),
     );
     expect(tester.takeException(), isNot(null));
@@ -494,35 +478,31 @@ void main() {
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://youtube.com',
-        // TODO(iskakaushik): Remove this when collection literals makes it to stable.
-        // ignore: prefer_collection_literals
-        javascriptChannels: <JavascriptChannel>[
+        javascriptChannels: <JavascriptChannel>{
           JavascriptChannel(
               name: 'Tts', onMessageReceived: (JavascriptMessage msg) {}),
           JavascriptChannel(
               name: 'Alarm', onMessageReceived: (JavascriptMessage msg) {}),
-        ].toSet(),
+        },
       ),
     );
 
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://youtube.com',
-        // TODO(iskakaushik): Remove this when collection literals makes it to stable.
-        // ignore: prefer_collection_literals
-        javascriptChannels: <JavascriptChannel>[
+        javascriptChannels: <JavascriptChannel>{
           JavascriptChannel(
               name: 'Tts', onMessageReceived: (JavascriptMessage msg) {}),
           JavascriptChannel(
               name: 'Alarm2', onMessageReceived: (JavascriptMessage msg) {}),
           JavascriptChannel(
               name: 'Alarm3', onMessageReceived: (JavascriptMessage msg) {}),
-        ].toSet(),
+        },
       ),
     );
 
     final FakePlatformWebView platformWebView =
-        fakePlatformViewsController.lastCreatedView;
+        fakePlatformViewsController.lastCreatedView!;
 
     expect(platformWebView.javascriptChannelNames,
         unorderedEquals(<String>['Tts', 'Alarm2', 'Alarm3']));
@@ -537,12 +517,10 @@ void main() {
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://youtube.com',
-        // TODO(iskakaushik): Remove this when collection literals makes it to stable.
-        // ignore: prefer_collection_literals
-        javascriptChannels: <JavascriptChannel>[
+        javascriptChannels: <JavascriptChannel>{
           JavascriptChannel(
               name: 'Tts', onMessageReceived: (JavascriptMessage msg) {}),
-        ].toSet(),
+        },
       ),
     );
 
@@ -555,17 +533,15 @@ void main() {
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://youtube.com',
-        // TODO(iskakaushik): Remove this when collection literals makes it to stable.
-        // ignore: prefer_collection_literals
-        javascriptChannels: <JavascriptChannel>[
+        javascriptChannels: <JavascriptChannel>{
           JavascriptChannel(
               name: 'Tts', onMessageReceived: (JavascriptMessage msg) {}),
-        ].toSet(),
+        },
       ),
     );
 
     final FakePlatformWebView platformWebView =
-        fakePlatformViewsController.lastCreatedView;
+        fakePlatformViewsController.lastCreatedView!;
 
     expect(platformWebView.javascriptChannelNames,
         unorderedEquals(<String>['Tts']));
@@ -577,9 +553,7 @@ void main() {
     await tester.pumpWidget(
       WebView(
         initialUrl: 'https://youtube.com',
-        // TODO(iskakaushik): Remove this when collection literals makes it to stable.
-        // ignore: prefer_collection_literals
-        javascriptChannels: <JavascriptChannel>[
+        javascriptChannels: <JavascriptChannel>{
           JavascriptChannel(
               name: 'Tts',
               onMessageReceived: (JavascriptMessage msg) {
@@ -590,12 +564,12 @@ void main() {
               onMessageReceived: (JavascriptMessage msg) {
                 alarmMessagesReceived.add(msg.message);
               }),
-        ].toSet(),
+        },
       ),
     );
 
     final FakePlatformWebView platformWebView =
-        fakePlatformViewsController.lastCreatedView;
+        fakePlatformViewsController.lastCreatedView!;
 
     expect(ttsMessagesReceived, isEmpty);
     expect(alarmMessagesReceived, isEmpty);
@@ -608,7 +582,7 @@ void main() {
 
   group('$PageStartedCallback', () {
     testWidgets('onPageStarted is not null', (WidgetTester tester) async {
-      String returnedUrl;
+      String? returnedUrl;
 
       await tester.pumpWidget(WebView(
         initialUrl: 'https://youtube.com',
@@ -618,7 +592,7 @@ void main() {
       ));
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       platformWebView.fakeOnPageStartedCallback();
 
@@ -632,7 +606,7 @@ void main() {
       ));
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       // The platform side will always invoke a call for onPageStarted. This is
       // to test that it does not crash on a null callback.
@@ -640,7 +614,7 @@ void main() {
     });
 
     testWidgets('onPageStarted changed', (WidgetTester tester) async {
-      String returnedUrl;
+      String? returnedUrl;
 
       await tester.pumpWidget(WebView(
         initialUrl: 'https://youtube.com',
@@ -655,7 +629,7 @@ void main() {
       ));
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       platformWebView.fakeOnPageStartedCallback();
 
@@ -665,7 +639,7 @@ void main() {
 
   group('$PageFinishedCallback', () {
     testWidgets('onPageFinished is not null', (WidgetTester tester) async {
-      String returnedUrl;
+      String? returnedUrl;
 
       await tester.pumpWidget(WebView(
         initialUrl: 'https://youtube.com',
@@ -675,7 +649,7 @@ void main() {
       ));
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       platformWebView.fakeOnPageFinishedCallback();
 
@@ -689,7 +663,7 @@ void main() {
       ));
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       // The platform side will always invoke a call for onPageFinished. This is
       // to test that it does not crash on a null callback.
@@ -697,7 +671,7 @@ void main() {
     });
 
     testWidgets('onPageFinished changed', (WidgetTester tester) async {
-      String returnedUrl;
+      String? returnedUrl;
 
       await tester.pumpWidget(WebView(
         initialUrl: 'https://youtube.com',
@@ -712,7 +686,7 @@ void main() {
       ));
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       platformWebView.fakeOnPageFinishedCallback();
 
@@ -720,6 +694,62 @@ void main() {
     });
   });
 
+  group('$PageLoadingCallback', () {
+    testWidgets('onLoadingProgress is not null', (WidgetTester tester) async {
+      int? loadingProgress;
+
+      await tester.pumpWidget(WebView(
+        initialUrl: 'https://youtube.com',
+        onProgress: (int progress) {
+          loadingProgress = progress;
+        },
+      ));
+
+      final FakePlatformWebView? platformWebView =
+          fakePlatformViewsController.lastCreatedView;
+
+      platformWebView?.fakeOnProgressCallback(50);
+
+      expect(loadingProgress, 50);
+    });
+
+    testWidgets('onLoadingProgress is null', (WidgetTester tester) async {
+      await tester.pumpWidget(const WebView(
+        initialUrl: 'https://youtube.com',
+        onProgress: null,
+      ));
+
+      final FakePlatformWebView platformWebView =
+          fakePlatformViewsController.lastCreatedView!;
+
+      // This is to test that it does not crash on a null callback.
+      platformWebView.fakeOnProgressCallback(50);
+    });
+
+    testWidgets('onLoadingProgress changed', (WidgetTester tester) async {
+      int? loadingProgress;
+
+      await tester.pumpWidget(WebView(
+        initialUrl: 'https://youtube.com',
+        onProgress: (int progress) {},
+      ));
+
+      await tester.pumpWidget(WebView(
+        initialUrl: 'https://youtube.com',
+        onProgress: (int progress) {
+          loadingProgress = progress;
+        },
+      ));
+
+      final FakePlatformWebView platformWebView =
+          fakePlatformViewsController.lastCreatedView!;
+
+      platformWebView.fakeOnProgressCallback(50);
+
+      expect(loadingProgress, 50);
+    });
+  });
+
   group('navigationDelegate', () {
     testWidgets('hasNavigationDelegate', (WidgetTester tester) async {
       await tester.pumpWidget(const WebView(
@@ -727,13 +757,14 @@ void main() {
       ));
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       expect(platformWebView.hasNavigationDelegate, false);
 
       await tester.pumpWidget(WebView(
         initialUrl: 'https://youtube.com',
-        navigationDelegate: (NavigationRequest r) => null,
+        navigationDelegate: (NavigationRequest r) =>
+            NavigationDecision.navigate,
       ));
 
       expect(platformWebView.hasNavigationDelegate, true);
@@ -753,7 +784,7 @@ void main() {
           }));
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       expect(platformWebView.hasNavigationDelegate, true);
 
@@ -778,7 +809,7 @@ void main() {
       ));
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       expect(platformWebView.debuggingEnabled, true);
     });
@@ -787,7 +818,7 @@ void main() {
       await tester.pumpWidget(const WebView());
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       expect(platformWebView.debuggingEnabled, false);
     });
@@ -797,7 +828,7 @@ void main() {
       await tester.pumpWidget(WebView(key: key));
 
       final FakePlatformWebView platformWebView =
-          fakePlatformViewsController.lastCreatedView;
+          fakePlatformViewsController.lastCreatedView!;
 
       await tester.pumpWidget(WebView(
         key: key,
@@ -833,8 +864,8 @@ void main() {
         ),
       );
 
-      final MyWebViewPlatform builder = WebView.platform;
-      final MyWebViewPlatformController platform = builder.lastPlatformBuilt;
+      final MyWebViewPlatform builder = WebView.platform as MyWebViewPlatform;
+      final MyWebViewPlatformController platform = builder.lastPlatformBuilt!;
 
       expect(
           platform.creationParams,
@@ -844,17 +875,14 @@ void main() {
               javascriptMode: JavascriptMode.disabled,
               hasNavigationDelegate: false,
               debuggingEnabled: false,
-              userAgent: WebSetting<String>.of(null),
+              userAgent: WebSetting<String?>.of(null),
               gestureNavigationEnabled: true,
             ),
-            // TODO(iskakaushik): Remove this when collection literals makes it to stable.
-            // ignore: prefer_collection_literals
-            javascriptChannelNames: Set<String>(),
           )));
     });
 
     testWidgets('loadUrl', (WidgetTester tester) async {
-      WebViewController controller;
+      late WebViewController controller;
       await tester.pumpWidget(
         WebView(
           initialUrl: 'https://youtube.com',
@@ -864,8 +892,8 @@ void main() {
         ),
       );
 
-      final MyWebViewPlatform builder = WebView.platform;
-      final MyWebViewPlatformController platform = builder.lastPlatformBuilt;
+      final MyWebViewPlatform builder = WebView.platform as MyWebViewPlatform;
+      final MyWebViewPlatformController platform = builder.lastPlatformBuilt!;
 
       final Map<String, String> headers = <String, String>{
         'header': 'value',
@@ -885,7 +913,7 @@ void main() {
     ));
 
     final FakePlatformWebView platformWebView =
-        fakePlatformViewsController.lastCreatedView;
+        fakePlatformViewsController.lastCreatedView!;
 
     expect(platformWebView.userAgent, isNull);
 
@@ -900,9 +928,9 @@ void main() {
 }
 
 class FakePlatformWebView {
-  FakePlatformWebView(int id, Map<dynamic, dynamic> params) {
+  FakePlatformWebView(int? id, Map<dynamic, dynamic> params) {
     if (params.containsKey('initialUrl')) {
-      final String initialUrl = params['initialUrl'];
+      final String? initialUrl = params['initialUrl'];
       if (initialUrl != null) {
         history.add(initialUrl);
         currentPosition++;
@@ -922,20 +950,20 @@ class FakePlatformWebView {
     channel.setMockMethodCallHandler(onMethodCall);
   }
 
-  MethodChannel channel;
+  late MethodChannel channel;
 
-  List<String> history = <String>[];
+  List<String?> history = <String?>[];
   int currentPosition = -1;
   int amountOfReloadsOnCurrentUrl = 0;
   bool hasCache = true;
 
-  String get currentUrl => history.isEmpty ? null : history[currentPosition];
-  JavascriptMode javascriptMode;
-  List<String> javascriptChannelNames;
+  String? get currentUrl => history.isEmpty ? null : history[currentPosition];
+  JavascriptMode? javascriptMode;
+  List<String>? javascriptChannelNames;
 
-  bool hasNavigationDelegate;
-  bool debuggingEnabled;
-  String userAgent;
+  bool? hasNavigationDelegate;
+  bool? debuggingEnabled;
+  String? userAgent;
 
   Future<dynamic> onMethodCall(MethodCall call) {
     switch (call.method) {
@@ -957,34 +985,28 @@ class FakePlatformWebView {
         break;
       case 'canGoBack':
         return Future<bool>.sync(() => currentPosition > 0);
-        break;
       case 'canGoForward':
         return Future<bool>.sync(() => currentPosition < history.length - 1);
-        break;
       case 'goBack':
         currentPosition = max(-1, currentPosition - 1);
         return Future<void>.sync(() {});
-        break;
       case 'goForward':
         currentPosition = min(history.length - 1, currentPosition + 1);
         return Future<void>.sync(() {});
       case 'reload':
         amountOfReloadsOnCurrentUrl++;
         return Future<void>.sync(() {});
-        break;
       case 'currentUrl':
-        return Future<String>.value(currentUrl);
-        break;
+        return Future<String?>.value(currentUrl);
       case 'evaluateJavascript':
         return Future<dynamic>.value(call.arguments);
-        break;
       case 'addJavascriptChannels':
         final List<String> channelNames = List<String>.from(call.arguments);
-        javascriptChannelNames.addAll(channelNames);
+        javascriptChannelNames!.addAll(channelNames);
         break;
       case 'removeJavascriptChannels':
         final List<String> channelNames = List<String>.from(call.arguments);
-        javascriptChannelNames
+        javascriptChannelNames!
             .removeWhere((String channel) => channelNames.contains(channel));
         break;
       case 'clearCache':
@@ -1002,14 +1024,15 @@ class FakePlatformWebView {
     };
     final ByteData data = codec
         .encodeMethodCall(MethodCall('javascriptChannelMessage', arguments));
-    ServicesBinding.instance.defaultBinaryMessenger
-        .handlePlatformMessage(channel.name, data, (ByteData data) {});
+    _ambiguate(ServicesBinding.instance)!
+        .defaultBinaryMessenger
+        .handlePlatformMessage(channel.name, data, (ByteData? data) {});
   }
 
   // Fakes a main frame navigation that was initiated by the webview, e.g when
   // the user clicks a link in the currently loaded page.
   void fakeNavigate(String url) {
-    if (!hasNavigationDelegate) {
+    if (!hasNavigationDelegate!) {
       print('no navigation delegate');
       _loadUrl(url);
       return;
@@ -1021,9 +1044,10 @@ class FakePlatformWebView {
     };
     final ByteData data =
         codec.encodeMethodCall(MethodCall('navigationRequest', arguments));
-    ServicesBinding.instance.defaultBinaryMessenger
-        .handlePlatformMessage(channel.name, data, (ByteData data) {
-      final bool allow = codec.decodeEnvelope(data);
+    _ambiguate(ServicesBinding.instance)!
+        .defaultBinaryMessenger
+        .handlePlatformMessage(channel.name, data, (ByteData? data) {
+      final bool allow = codec.decodeEnvelope(data!);
       if (allow) {
         _loadUrl(url);
       }
@@ -1038,11 +1062,13 @@ class FakePlatformWebView {
       <dynamic, dynamic>{'url': currentUrl},
     ));
 
-    ServicesBinding.instance.defaultBinaryMessenger.handlePlatformMessage(
-      channel.name,
-      data,
-      (ByteData data) {},
-    );
+    _ambiguate(ServicesBinding.instance)!
+        .defaultBinaryMessenger
+        .handlePlatformMessage(
+          channel.name,
+          data,
+          (ByteData? data) {},
+        );
   }
 
   void fakeOnPageFinishedCallback() {
@@ -1053,14 +1079,29 @@ class FakePlatformWebView {
       <dynamic, dynamic>{'url': currentUrl},
     ));
 
-    ServicesBinding.instance.defaultBinaryMessenger.handlePlatformMessage(
-      channel.name,
-      data,
-      (ByteData data) {},
-    );
+    _ambiguate(ServicesBinding.instance)!
+        .defaultBinaryMessenger
+        .handlePlatformMessage(
+          channel.name,
+          data,
+          (ByteData? data) {},
+        );
+  }
+
+  void fakeOnProgressCallback(int progress) {
+    final StandardMethodCodec codec = const StandardMethodCodec();
+
+    final ByteData data = codec.encodeMethodCall(MethodCall(
+      'onProgress',
+      <dynamic, dynamic>{'progress': progress},
+    ));
+
+    _ambiguate(ServicesBinding.instance)!
+        .defaultBinaryMessenger
+        .handlePlatformMessage(channel.name, data, (ByteData? data) {});
   }
 
-  void _loadUrl(String url) {
+  void _loadUrl(String? url) {
     history = history.sublist(0, currentPosition + 1);
     history.add(url);
     currentPosition++;
@@ -1069,13 +1110,13 @@ class FakePlatformWebView {
 }
 
 class _FakePlatformViewsController {
-  FakePlatformWebView lastCreatedView;
+  FakePlatformWebView? lastCreatedView;
 
   Future<dynamic> fakePlatformViewsMethodHandler(MethodCall call) {
     switch (call.method) {
       case 'create':
         final Map<dynamic, dynamic> args = call.arguments;
-        final Map<dynamic, dynamic> params = _decodeParams(args['params']);
+        final Map<dynamic, dynamic> params = _decodeParams(args['params'])!;
         lastCreatedView = FakePlatformWebView(
           args['id'],
           params,
@@ -1091,7 +1132,7 @@ class _FakePlatformViewsController {
   }
 }
 
-Map<dynamic, dynamic> _decodeParams(Uint8List paramsMessage) {
+Map<dynamic, dynamic>? _decodeParams(Uint8List paramsMessage) {
   final ByteBuffer buffer = paramsMessage.buffer;
   final ByteData messageBytes = buffer.asByteData(
     paramsMessage.offsetInBytes,
@@ -1122,9 +1163,8 @@ class _FakeCookieManager {
         return Future<bool>.sync(() {
           return hadCookies;
         });
-        break;
     }
-    return Future<bool>.sync(() => null);
+    return Future<bool>.sync(() => true);
   }
 
   void reset() {
@@ -1133,26 +1173,27 @@ class _FakeCookieManager {
 }
 
 class MyWebViewPlatform implements WebViewPlatform {
-  MyWebViewPlatformController lastPlatformBuilt;
+  MyWebViewPlatformController? lastPlatformBuilt;
 
   @override
   Widget build({
-    BuildContext context,
-    CreationParams creationParams,
-    @required WebViewPlatformCallbacksHandler webViewPlatformCallbacksHandler,
-    @required WebViewPlatformCreatedCallback onWebViewPlatformCreated,
-    Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers,
+    BuildContext? context,
+    CreationParams? creationParams,
+    required WebViewPlatformCallbacksHandler webViewPlatformCallbacksHandler,
+    required JavascriptChannelRegistry javascriptChannelRegistry,
+    WebViewPlatformCreatedCallback? onWebViewPlatformCreated,
+    Set<Factory<OneSequenceGestureRecognizer>>? gestureRecognizers,
   }) {
     assert(onWebViewPlatformCreated != null);
     lastPlatformBuilt = MyWebViewPlatformController(
         creationParams, gestureRecognizers, webViewPlatformCallbacksHandler);
-    onWebViewPlatformCreated(lastPlatformBuilt);
+    onWebViewPlatformCreated!(lastPlatformBuilt);
     return Container();
   }
 
   @override
   Future<bool> clearCookies() {
-    return Future<bool>.sync(() => null);
+    return Future<bool>.sync(() => true);
   }
 }
 
@@ -1161,25 +1202,24 @@ class MyWebViewPlatformController extends WebViewPlatformController {
       WebViewPlatformCallbacksHandler platformHandler)
       : super(platformHandler);
 
-  CreationParams creationParams;
-  Set<Factory<OneSequenceGestureRecognizer>> gestureRecognizers;
+  CreationParams? creationParams;
+  Set<Factory<OneSequenceGestureRecognizer>>? gestureRecognizers;
 
-  String lastUrlLoaded;
-  Map<String, String> lastRequestHeaders;
+  String? lastUrlLoaded;
+  Map<String, String>? lastRequestHeaders;
 
   @override
-  Future<void> loadUrl(String url, Map<String, String> headers) {
+  Future<void> loadUrl(String url, Map<String, String>? headers) async {
     equals(1, 1);
     lastUrlLoaded = url;
     lastRequestHeaders = headers;
-    return null;
   }
 }
 
 class MatchesWebSettings extends Matcher {
   MatchesWebSettings(this._webSettings);
 
-  final WebSettings _webSettings;
+  final WebSettings? _webSettings;
 
   @override
   Description describe(Description description) =>
@@ -1188,13 +1228,13 @@ class MatchesWebSettings extends Matcher {
   @override
   bool matches(
       covariant WebSettings webSettings, Map<dynamic, dynamic> matchState) {
-    return _webSettings.javascriptMode == webSettings.javascriptMode &&
-        _webSettings.hasNavigationDelegate ==
+    return _webSettings!.javascriptMode == webSettings.javascriptMode &&
+        _webSettings!.hasNavigationDelegate ==
             webSettings.hasNavigationDelegate &&
-        _webSettings.debuggingEnabled == webSettings.debuggingEnabled &&
-        _webSettings.gestureNavigationEnabled ==
+        _webSettings!.debuggingEnabled == webSettings.debuggingEnabled &&
+        _webSettings!.gestureNavigationEnabled ==
             webSettings.gestureNavigationEnabled &&
-        _webSettings.userAgent == webSettings.userAgent;
+        _webSettings!.userAgent == webSettings.userAgent;
   }
 }
 
@@ -1212,8 +1252,15 @@ class MatchesCreationParams extends Matcher {
       Map<dynamic, dynamic> matchState) {
     return _creationParams.initialUrl == creationParams.initialUrl &&
         MatchesWebSettings(_creationParams.webSettings)
-            .matches(creationParams.webSettings, matchState) &&
+            .matches(creationParams.webSettings!, matchState) &&
         orderedEquals(_creationParams.javascriptChannelNames)
             .matches(creationParams.javascriptChannelNames, matchState);
   }
 }
+
+/// This allows a value of type T or T? to be treated as a value of type T?.
+///
+/// We use this so that APIs that have become non-nullable can still be used
+/// with `!` and `?` on the stable branch.
+// TODO(ianh): Remove this once we roll stable in late 2021.
+T? _ambiguate<T>(T? value) => value;
diff --git a/packages/webview_flutter/example/pubspec.yaml b/packages/webview_flutter/example/pubspec.yaml
index 39f3042b9..3b72359a3 100644
--- a/packages/webview_flutter/example/pubspec.yaml
+++ b/packages/webview_flutter/example/pubspec.yaml
@@ -2,20 +2,23 @@ name: webview_flutter_tizen_example
 description: Demonstrates how to use the webview_flutter_tizen plugin.
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=2.0.0"
+  sdk: ">=2.14.0 <3.0.0"
+  flutter: ">=2.5.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  webview_flutter: ^2.0.4
+  webview_flutter: ^2.1.1
   webview_flutter_tizen:
     path: ../
 
 dev_dependencies:
   flutter_driver:
     sdk: flutter
-  integration_test: ^1.0.1
+  flutter_test:
+    sdk: flutter
+  integration_test:
+    sdk: flutter
   integration_test_tizen:
     path: ../../integration_test/
   pedantic: ^1.10.0
diff --git a/packages/webview_flutter/lib/src/platform_view.dart b/packages/webview_flutter/lib/src/platform_view.dart
index c607cf57e..e5474e966 100644
--- a/packages/webview_flutter/lib/src/platform_view.dart
+++ b/packages/webview_flutter/lib/src/platform_view.dart
@@ -41,8 +41,8 @@ class _PlatformViewGestureRecognizer extends OneSequenceGestureRecognizer {
   _PlatformViewGestureRecognizer(
     _HandlePointerEvent handlePointerEvent,
     this.gestureRecognizerFactories, {
-    PointerDeviceKind? kind,
-  }) : super(kind: kind) {
+    Set<PointerDeviceKind>? supportedDevices,
+  }) : super(supportedDevices: supportedDevices) {
     team = GestureArenaTeam()..captain = this;
     _gestureRecognizers = gestureRecognizerFactories.map(
       (Factory<OneSequenceGestureRecognizer> recognizerFactory) {
diff --git a/packages/webview_flutter/lib/src/platform_view_tizen.dart b/packages/webview_flutter/lib/src/platform_view_tizen.dart
index 03722f7bc..7bc568f55 100644
--- a/packages/webview_flutter/lib/src/platform_view_tizen.dart
+++ b/packages/webview_flutter/lib/src/platform_view_tizen.dart
@@ -10,6 +10,8 @@
 // Imported from above files, the content has been minimally modified.
 // (e.g. Rename keyword 'Android' -> 'Tizen' )
 
+// ignore_for_file: public_member_api_docs
+
 part of '../webview_flutter_tizen.dart';
 
 class TizenView extends StatefulWidget {
diff --git a/packages/webview_flutter/lib/webview_flutter_tizen.dart b/packages/webview_flutter/lib/webview_flutter_tizen.dart
index f9dc36cc0..c765b3d14 100644
--- a/packages/webview_flutter/lib/webview_flutter_tizen.dart
+++ b/packages/webview_flutter/lib/webview_flutter_tizen.dart
@@ -15,7 +15,8 @@ import 'package:flutter/rendering.dart';
 
 import 'package:webview_flutter/webview_flutter.dart';
 import 'package:webview_flutter/platform_interface.dart';
-import 'package:webview_flutter/src/webview_method_channel.dart';
+import 'package:webview_flutter_platform_interface/src/method_channel/webview_method_channel.dart';
+import 'package:webview_flutter_platform_interface/webview_flutter_platform_interface.dart';
 
 part 'src/platform_view.dart';
 part 'src/platform_view_tizen.dart';
@@ -25,6 +26,7 @@ part 'src/platform_view_tizen.dart';
 /// This is used as the default implementation for [WebView.platform] on Tizen. It uses a method channel to
 /// communicate with the platform code.
 class TizenWebView implements WebViewPlatform {
+  /// Sets a tizen [WebViewPlatform].
   static void register() {
     WebView.platform = TizenWebView();
   }
@@ -33,9 +35,10 @@ class TizenWebView implements WebViewPlatform {
   Widget build({
     required BuildContext context,
     required CreationParams creationParams,
+    required WebViewPlatformCallbacksHandler webViewPlatformCallbacksHandler,
+    required JavascriptChannelRegistry javascriptChannelRegistry,
     WebViewPlatformCreatedCallback? onWebViewPlatformCreated,
     Set<Factory<OneSequenceGestureRecognizer>>? gestureRecognizers,
-    required WebViewPlatformCallbacksHandler webViewPlatformCallbacksHandler,
   }) {
     assert(webViewPlatformCallbacksHandler != null);
     return GestureDetector(
@@ -48,10 +51,13 @@ class TizenWebView implements WebViewPlatform {
             return;
           }
           onWebViewPlatformCreated(MethodChannelWebViewPlatform(
-              id, webViewPlatformCallbacksHandler));
+            id,
+            webViewPlatformCallbacksHandler,
+            javascriptChannelRegistry,
+          ));
         },
         gestureRecognizers: gestureRecognizers,
-        layoutDirection: TextDirection.rtl,
+        layoutDirection: Directionality.maybeOf(context) ?? TextDirection.rtl,
         creationParams:
             MethodChannelWebViewPlatform.creationParamsToMap(creationParams),
         creationParamsCodec: const StandardMessageCodec(),
diff --git a/packages/webview_flutter/pubspec.yaml b/packages/webview_flutter/pubspec.yaml
index 666d7d4b3..9a4ad11be 100644
--- a/packages/webview_flutter/pubspec.yaml
+++ b/packages/webview_flutter/pubspec.yaml
@@ -1,16 +1,17 @@
 name: webview_flutter_tizen
 description: Tizen implementation of the webview plugin
 homepage: https://github.com/flutter-tizen/plugins
-version: 0.3.6
+version: 0.3.7
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=2.0.0"
+  sdk: ">=2.14.0 <3.0.0"
+  flutter: ">=2.5.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  webview_flutter: ^2.0.4
+  webview_flutter_platform_interface: ^1.0.0
+  webview_flutter: ^2.1.1
 
 dev_dependencies:
   flutter_test: