diff --git a/animations/ios/Runner.xcodeproj/project.pbxproj b/animations/ios/Runner.xcodeproj/project.pbxproj
index b7ef4c45fe8..1b8fd3034da 100644
--- a/animations/ios/Runner.xcodeproj/project.pbxproj
+++ b/animations/ios/Runner.xcodeproj/project.pbxproj
@@ -9,11 +9,7 @@
 /* Begin PBXBuildFile section */
 		1498D2341E8E89220040F4C2 /* GeneratedPluginRegistrant.m in Sources */ = {isa = PBXBuildFile; fileRef = 1498D2331E8E89220040F4C2 /* GeneratedPluginRegistrant.m */; };
 		3B3967161E833CAA004F5970 /* AppFrameworkInfo.plist in Resources */ = {isa = PBXBuildFile; fileRef = 3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */; };
-		3B80C3941E831B6300D905FE /* App.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 3B80C3931E831B6300D905FE /* App.framework */; };
-		3B80C3951E831B6300D905FE /* App.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 3B80C3931E831B6300D905FE /* App.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		74858FAF1ED2DC5600515810 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 74858FAE1ED2DC5600515810 /* AppDelegate.swift */; };
-		9705A1C61CF904A100538489 /* Flutter.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 9740EEBA1CF902C7004384FC /* Flutter.framework */; };
-		9705A1C71CF904A300538489 /* Flutter.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 9740EEBA1CF902C7004384FC /* Flutter.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		97C146FC1CF9000F007C117D /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 97C146FA1CF9000F007C117D /* Main.storyboard */; };
 		97C146FE1CF9000F007C117D /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 97C146FD1CF9000F007C117D /* Assets.xcassets */; };
 		97C147011CF9000F007C117D /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 97C146FF1CF9000F007C117D /* LaunchScreen.storyboard */; };
@@ -26,8 +22,6 @@
 			dstPath = "";
 			dstSubfolderSpec = 10;
 			files = (
-				3B80C3951E831B6300D905FE /* App.framework in Embed Frameworks */,
-				9705A1C71CF904A300538489 /* Flutter.framework in Embed Frameworks */,
 			);
 			name = "Embed Frameworks";
 			runOnlyForDeploymentPostprocessing = 0;
@@ -38,13 +32,11 @@
 		1498D2321E8E86230040F4C2 /* GeneratedPluginRegistrant.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = GeneratedPluginRegistrant.h; sourceTree = "<group>"; };
 		1498D2331E8E89220040F4C2 /* GeneratedPluginRegistrant.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = GeneratedPluginRegistrant.m; sourceTree = "<group>"; };
 		3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; name = AppFrameworkInfo.plist; path = Flutter/AppFrameworkInfo.plist; sourceTree = "<group>"; };
-		3B80C3931E831B6300D905FE /* App.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = App.framework; path = Flutter/App.framework; sourceTree = "<group>"; };
 		74858FAD1ED2DC5600515810 /* Runner-Bridging-Header.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "Runner-Bridging-Header.h"; sourceTree = "<group>"; };
 		74858FAE1ED2DC5600515810 /* AppDelegate.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
 		7AFA3C8E1D35360C0083082E /* Release.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; name = Release.xcconfig; path = Flutter/Release.xcconfig; sourceTree = "<group>"; };
 		9740EEB21CF90195004384FC /* Debug.xcconfig */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xcconfig; name = Debug.xcconfig; path = Flutter/Debug.xcconfig; sourceTree = "<group>"; };
 		9740EEB31CF90195004384FC /* Generated.xcconfig */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xcconfig; name = Generated.xcconfig; path = Flutter/Generated.xcconfig; sourceTree = "<group>"; };
-		9740EEBA1CF902C7004384FC /* Flutter.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Flutter.framework; path = Flutter/Flutter.framework; sourceTree = "<group>"; };
 		97C146EE1CF9000F007C117D /* Runner.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Runner.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		97C146FB1CF9000F007C117D /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/Main.storyboard; sourceTree = "<group>"; };
 		97C146FD1CF9000F007C117D /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
@@ -57,8 +49,6 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				9705A1C61CF904A100538489 /* Flutter.framework in Frameworks */,
-				3B80C3941E831B6300D905FE /* App.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -68,9 +58,7 @@
 		9740EEB11CF90186004384FC /* Flutter */ = {
 			isa = PBXGroup;
 			children = (
-				3B80C3931E831B6300D905FE /* App.framework */,
 				3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */,
-				9740EEBA1CF902C7004384FC /* Flutter.framework */,
 				9740EEB21CF90195004384FC /* Debug.xcconfig */,
 				7AFA3C8E1D35360C0083082E /* Release.xcconfig */,
 				9740EEB31CF90195004384FC /* Generated.xcconfig */,
@@ -201,7 +189,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "/bin/sh \"$FLUTTER_ROOT/packages/flutter_tools/bin/xcode_backend.sh\" thin";
+			shellScript = "/bin/sh \"$FLUTTER_ROOT/packages/flutter_tools/bin/xcode_backend.sh\" embed_and_thin";
 		};
 		9740EEB61CF901F6004384FC /* Run Script */ = {
 			isa = PBXShellScriptBuildPhase;
@@ -253,7 +241,6 @@
 /* Begin XCBuildConfiguration section */
 		249021D3217E4FDB00AE95B9 /* Profile */ = {
 			isa = XCBuildConfiguration;
-			baseConfigurationReference = 7AFA3C8E1D35360C0083082E /* Release.xcconfig */;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				CLANG_ANALYZER_NONNULL = YES;
@@ -330,7 +317,6 @@
 		};
 		97C147031CF9000F007C117D /* Debug */ = {
 			isa = XCBuildConfiguration;
-			baseConfigurationReference = 9740EEB21CF90195004384FC /* Debug.xcconfig */;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				CLANG_ANALYZER_NONNULL = YES;
@@ -386,7 +372,6 @@
 		};
 		97C147041CF9000F007C117D /* Release */ = {
 			isa = XCBuildConfiguration;
-			baseConfigurationReference = 7AFA3C8E1D35360C0083082E /* Release.xcconfig */;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				CLANG_ANALYZER_NONNULL = YES;
diff --git a/animations/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata b/animations/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata
index 1d526a16ed0..919434a6254 100644
--- a/animations/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata
+++ b/animations/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata
@@ -2,6 +2,6 @@
 <Workspace
    version = "1.0">
    <FileRef
-      location = "group:Runner.xcodeproj">
+      location = "self:">
    </FileRef>
 </Workspace>
diff --git a/animations/lib/main.dart b/animations/lib/main.dart
index eee14aa142c..b74b957bf3b 100644
--- a/animations/lib/main.dart
+++ b/animations/lib/main.dart
@@ -31,7 +31,11 @@ class Demo {
   final String route;
   final WidgetBuilder builder;
 
-  const Demo({this.name, this.route, this.builder});
+  const Demo({
+    required this.name,
+    required this.route,
+    required this.builder,
+  });
 }
 
 final basicDemos = [
diff --git a/animations/lib/src/basics/01_animated_container.dart b/animations/lib/src/basics/01_animated_container.dart
index 9b84fd4e6d4..e009f43ff84 100644
--- a/animations/lib/src/basics/01_animated_container.dart
+++ b/animations/lib/src/basics/01_animated_container.dart
@@ -18,9 +18,9 @@ class AnimatedContainerDemo extends StatefulWidget {
 }
 
 class _AnimatedContainerDemoState extends State<AnimatedContainerDemo> {
-  Color color;
-  double borderRadius;
-  double margin;
+  late Color color;
+  late double borderRadius;
+  late double margin;
 
   @override
   void initState() {
diff --git a/animations/lib/src/basics/03_animation_controller.dart b/animations/lib/src/basics/03_animation_controller.dart
index a9d46f35bbb..3a88bfebe49 100644
--- a/animations/lib/src/basics/03_animation_controller.dart
+++ b/animations/lib/src/basics/03_animation_controller.dart
@@ -20,7 +20,7 @@ class _AnimationControllerDemoState extends State<AnimationControllerDemo>
   // Widget is not visible.
 
   static const Duration _duration = Duration(seconds: 1);
-  AnimationController controller;
+  late final AnimationController controller;
 
   @override
   void initState() {
diff --git a/animations/lib/src/basics/04_tweens.dart b/animations/lib/src/basics/04_tweens.dart
index 9ed9822aaa6..1984f8b0ca1 100644
--- a/animations/lib/src/basics/04_tweens.dart
+++ b/animations/lib/src/basics/04_tweens.dart
@@ -15,8 +15,8 @@ class _TweenDemoState extends State<TweenDemo>
     with SingleTickerProviderStateMixin {
   static const Duration _duration = Duration(seconds: 1);
   static const double accountBalance = 1000000;
-  AnimationController controller;
-  Animation<double> animation;
+  late final AnimationController controller;
+  late final Animation<double> animation;
 
   @override
   void initState() {
diff --git a/animations/lib/src/basics/05_animated_builder.dart b/animations/lib/src/basics/05_animated_builder.dart
index 70919886c92..10d7f0dbe05 100644
--- a/animations/lib/src/basics/05_animated_builder.dart
+++ b/animations/lib/src/basics/05_animated_builder.dart
@@ -16,8 +16,8 @@ class _AnimatedBuilderDemoState extends State<AnimatedBuilderDemo>
   static const Color beginColor = Colors.deepPurple;
   static const Color endColor = Colors.deepOrange;
   Duration duration = Duration(milliseconds: 800);
-  AnimationController controller;
-  Animation<Color> animation;
+  late AnimationController controller;
+  late Animation<Color?> animation;
 
   @override
   void initState() {
diff --git a/animations/lib/src/basics/06_custom_tween.dart b/animations/lib/src/basics/06_custom_tween.dart
index 4c2ce48e1f9..87471a449b3 100644
--- a/animations/lib/src/basics/06_custom_tween.dart
+++ b/animations/lib/src/basics/06_custom_tween.dart
@@ -5,13 +5,13 @@
 import 'package:flutter/material.dart';
 
 class TypewriterTween extends Tween<String> {
-  TypewriterTween({String begin = '', String end})
+  TypewriterTween({String begin = '', String end = ''})
       : super(begin: begin, end: end);
 
   @override
   String lerp(double t) {
-    var cutoff = (end.length * t).round();
-    return end.substring(0, cutoff);
+    var cutoff = (end!.length * t).round();
+    return end!.substring(0, cutoff);
   }
 }
 
@@ -26,8 +26,8 @@ class _CustomTweenDemoState extends State<CustomTweenDemo>
     with SingleTickerProviderStateMixin {
   static const Duration _duration = Duration(seconds: 3);
   static const String message = loremIpsum;
-  AnimationController controller;
-  Animation<String> animation;
+  late final AnimationController controller;
+  late final Animation<String> animation;
 
   @override
   void initState() {
diff --git a/animations/lib/src/basics/07_tween_sequence.dart b/animations/lib/src/basics/07_tween_sequence.dart
index 231458777b2..59f98d6a145 100644
--- a/animations/lib/src/basics/07_tween_sequence.dart
+++ b/animations/lib/src/basics/07_tween_sequence.dart
@@ -14,8 +14,8 @@ class TweenSequenceDemo extends StatefulWidget {
 class _TweenSequenceDemoState extends State<TweenSequenceDemo>
     with SingleTickerProviderStateMixin {
   static const Duration duration = Duration(seconds: 3);
-  AnimationController controller;
-  Animation<Color> animation;
+  late final AnimationController controller;
+  late final Animation<Color?> animation;
 
   static final colors = [
     Colors.red,
@@ -31,7 +31,7 @@ class _TweenSequenceDemoState extends State<TweenSequenceDemo>
   void initState() {
     super.initState();
 
-    final sequenceItems = <TweenSequenceItem<Color>>[];
+    final sequenceItems = <TweenSequenceItem<Color?>>[];
 
     for (var i = 0; i < colors.length; i++) {
       final beginColor = colors[i];
@@ -39,7 +39,7 @@ class _TweenSequenceDemoState extends State<TweenSequenceDemo>
       final weight = 1 / colors.length;
 
       sequenceItems.add(
-        TweenSequenceItem<Color>(
+        TweenSequenceItem<Color?>(
           tween: ColorTween(begin: beginColor, end: endColor),
           weight: weight,
         ),
@@ -47,7 +47,7 @@ class _TweenSequenceDemoState extends State<TweenSequenceDemo>
     }
 
     controller = AnimationController(duration: duration, vsync: this);
-    animation = TweenSequence<Color>(sequenceItems).animate(controller);
+    animation = TweenSequence<Color?>(sequenceItems).animate(controller);
   }
 
   @override
diff --git a/animations/lib/src/basics/08_fade_transition.dart b/animations/lib/src/basics/08_fade_transition.dart
index 4d04dad19a1..15e5817cf53 100644
--- a/animations/lib/src/basics/08_fade_transition.dart
+++ b/animations/lib/src/basics/08_fade_transition.dart
@@ -15,9 +15,9 @@ class FadeTransitionDemo extends StatefulWidget {
 
 class _FadeTransitionDemoState extends State<FadeTransitionDemo>
     with SingleTickerProviderStateMixin {
-  AnimationController _controller;
-  Animation<double> _animation;
-  CurvedAnimation _curve;
+  late final AnimationController _controller;
+  late final Animation<double> _animation;
+  late final CurvedAnimation _curve;
 
   @override
   void initState() {
diff --git a/animations/lib/src/misc/animated_list.dart b/animations/lib/src/misc/animated_list.dart
index 7c9aff2aee6..7c115c5202b 100644
--- a/animations/lib/src/misc/animated_list.dart
+++ b/animations/lib/src/misc/animated_list.dart
@@ -14,23 +14,31 @@ class AnimatedListDemo extends StatefulWidget {
 
 class _AnimatedListDemoState extends State<AnimatedListDemo> {
   final GlobalKey<AnimatedListState> _listKey = GlobalKey();
-  final listData = initialListData;
+  final listData = [
+    UserModel(0, 'Govind', 'Dixit'),
+    UserModel(1, 'Greta', 'Stoll'),
+    UserModel(2, 'Monty', 'Carlo'),
+    UserModel(3, 'Petey', 'Cruiser'),
+    UserModel(4, 'Barry', 'Cade'),
+  ];
+  final initialListSize = 5;
 
   void addUser() {
     setState(() {
       var index = listData.length;
       listData.add(
-        UserModel(firstName: 'New', lastName: 'Person'),
+        UserModel(++_maxIdValue, 'New', 'Person'),
       );
-      _listKey.currentState
+      _listKey.currentState!
           .insertItem(index, duration: Duration(milliseconds: 300));
     });
   }
 
-  void deleteUser(int index) {
+  void deleteUser(int id) {
     setState(() {
+      final index = listData.indexWhere((u) => u.id == id);
       var user = listData.removeAt(index);
-      _listKey.currentState.removeItem(
+      _listKey.currentState!.removeItem(
         index,
         (context, animation) {
           return FadeTransition(
@@ -49,7 +57,7 @@ class _AnimatedListDemoState extends State<AnimatedListDemo> {
     });
   }
 
-  Widget _buildItem(UserModel user, [int index]) {
+  Widget _buildItem(UserModel user) {
     return ListTile(
       key: ValueKey<UserModel>(user),
       title: Text(user.firstName),
@@ -59,7 +67,7 @@ class _AnimatedListDemoState extends State<AnimatedListDemo> {
       ),
       trailing: IconButton(
         icon: Icon(Icons.delete),
-        onPressed: () => deleteUser(index),
+        onPressed: () => deleteUser(user.id),
       ),
     );
   }
@@ -79,11 +87,11 @@ class _AnimatedListDemoState extends State<AnimatedListDemo> {
       body: SafeArea(
         child: AnimatedList(
           key: _listKey,
-          initialItemCount: initialListData.length,
+          initialItemCount: 5,
           itemBuilder: (context, index, animation) {
             return FadeTransition(
               opacity: animation,
-              child: _buildItem(listData[index], index),
+              child: _buildItem(listData[index]),
             );
           },
         ),
@@ -93,31 +101,15 @@ class _AnimatedListDemoState extends State<AnimatedListDemo> {
 }
 
 class UserModel {
-  const UserModel({this.firstName, this.lastName});
+  UserModel(
+    this.id,
+    this.firstName,
+    this.lastName,
+  );
 
+  final int id;
   final String firstName;
   final String lastName;
 }
 
-List<UserModel> initialListData = [
-  UserModel(
-    firstName: 'Govind',
-    lastName: 'Dixit',
-  ),
-  UserModel(
-    firstName: 'Greta',
-    lastName: 'Stoll',
-  ),
-  UserModel(
-    firstName: 'Monty',
-    lastName: 'Carlo',
-  ),
-  UserModel(
-    firstName: 'Petey',
-    lastName: 'Cruiser',
-  ),
-  UserModel(
-    firstName: 'Barry',
-    lastName: 'Cade',
-  ),
-];
+int _maxIdValue = 4;
diff --git a/animations/lib/src/misc/animated_positioned.dart b/animations/lib/src/misc/animated_positioned.dart
index 641ff91eb81..a514e96a6f9 100644
--- a/animations/lib/src/misc/animated_positioned.dart
+++ b/animations/lib/src/misc/animated_positioned.dart
@@ -14,8 +14,8 @@ class AnimatedPositionedDemo extends StatefulWidget {
 }
 
 class _AnimatedPositionedDemoState extends State<AnimatedPositionedDemo> {
-  double topPosition;
-  double leftPosition;
+  late double topPosition;
+  late double leftPosition;
 
   double generateTopPosition(double top) => Random().nextDouble() * top;
 
@@ -41,40 +41,38 @@ class _AnimatedPositionedDemoState extends State<AnimatedPositionedDemo> {
     final appBar = AppBar(title: Text('AnimatedPositioned'));
     final topPadding = MediaQuery.of(context).padding.top;
     // AnimatedPositioned animates changes to a widget's position within a Stack
-    return SafeArea(
-      child: Scaffold(
-        appBar: appBar,
-        body: Container(
-          height: size.height,
-          width: size.width,
-          child: Stack(
-            children: [
-              AnimatedPositioned(
-                top: topPosition,
-                left: leftPosition,
-                duration: Duration(seconds: 1),
-                child: InkWell(
-                  onTap: () => changePosition(
-                      size.height -
-                          (appBar.preferredSize.height + topPadding + 50),
-                      size.width - 150),
-                  child: Container(
-                    alignment: Alignment.center,
-                    width: 150,
-                    height: 50,
-                    child: Text(
-                      'Click Me',
-                      style: TextStyle(
-                        color:
-                            Theme.of(context).buttonTheme.colorScheme.onPrimary,
-                      ),
+    return Scaffold(
+      appBar: appBar,
+      body: Container(
+        height: size.height,
+        width: size.width,
+        child: Stack(
+          children: [
+            AnimatedPositioned(
+              top: topPosition,
+              left: leftPosition,
+              duration: Duration(seconds: 1),
+              child: InkWell(
+                onTap: () => changePosition(
+                    size.height -
+                        (appBar.preferredSize.height + topPadding + 50),
+                    size.width - 150),
+                child: Container(
+                  alignment: Alignment.center,
+                  width: 150,
+                  height: 50,
+                  child: Text(
+                    'Click Me',
+                    style: TextStyle(
+                      color:
+                          Theme.of(context).buttonTheme.colorScheme!.onPrimary,
                     ),
-                    color: Theme.of(context).primaryColor,
                   ),
+                  color: Theme.of(context).primaryColor,
                 ),
               ),
-            ],
-          ),
+            ),
+          ],
         ),
       ),
     );
diff --git a/animations/lib/src/misc/animated_switcher.dart b/animations/lib/src/misc/animated_switcher.dart
index 4c316d23000..bbd6e445ca4 100644
--- a/animations/lib/src/misc/animated_switcher.dart
+++ b/animations/lib/src/misc/animated_switcher.dart
@@ -30,8 +30,8 @@ class AnimatedSwitcherDemo extends StatefulWidget {
 }
 
 class _AnimatedSwitcherDemoState extends State<AnimatedSwitcherDemo> {
-  Widget container;
-  int keyCount;
+  late Widget container;
+  late int keyCount;
 
   @override
   void initState() {
@@ -53,7 +53,7 @@ class _AnimatedSwitcherDemoState extends State<AnimatedSwitcherDemo> {
             child: Text(
               'Change Widget',
               style: TextStyle(
-                  color: Theme.of(context).buttonTheme.colorScheme.onPrimary),
+                  color: Theme.of(context).buttonTheme.colorScheme!.onPrimary),
             ),
           ),
         ],
diff --git a/animations/lib/src/misc/card_swipe.dart b/animations/lib/src/misc/card_swipe.dart
index d024816fb58..56f7d55c69d 100644
--- a/animations/lib/src/misc/card_swipe.dart
+++ b/animations/lib/src/misc/card_swipe.dart
@@ -15,7 +15,7 @@ class CardSwipeDemo extends StatefulWidget {
 }
 
 class _CardSwipeDemoState extends State<CardSwipeDemo> {
-  List<String> fileNames;
+  late List<String> fileNames;
 
   @override
   void initState() {
@@ -102,8 +102,8 @@ class SwipeableCard extends StatefulWidget {
   final VoidCallback onSwiped;
 
   SwipeableCard({
-    this.onSwiped,
-    this.imageAssetName,
+    required this.onSwiped,
+    required this.imageAssetName,
   });
 
   @override
@@ -112,9 +112,9 @@ class SwipeableCard extends StatefulWidget {
 
 class _SwipeableCardState extends State<SwipeableCard>
     with SingleTickerProviderStateMixin {
-  AnimationController _controller;
-  Animation<Offset> _animation;
-  double _dragStartX;
+  late AnimationController _controller;
+  late Animation<Offset> _animation;
+  late double _dragStartX;
   bool _isSwipingLeft = false;
 
   @override
@@ -155,18 +155,29 @@ class _SwipeableCardState extends State<SwipeableCard>
     }
 
     setState(() {
+      final size = context.size;
+
+      if (size == null) {
+        return;
+      }
+
       // Calculate the amount dragged in unit coordinates (between 0 and 1)
       // using this widgets width.
       _controller.value =
-          (details.localPosition.dx - _dragStartX).abs() / context.size.width;
+          (details.localPosition.dx - _dragStartX).abs() / size.width;
     });
   }
 
   /// Runs the fling / spring animation using the final velocity of the drag
   /// gesture.
   void _dragEnd(DragEndDetails details) {
-    var velocity =
-        (details.velocity.pixelsPerSecond.dx / context.size.width).abs();
+    final size = context.size;
+
+    if (size == null) {
+      return;
+    }
+
+    var velocity = (details.velocity.pixelsPerSecond.dx / size.width).abs();
     _animate(velocity: velocity);
   }
 
diff --git a/animations/lib/src/misc/carousel.dart b/animations/lib/src/misc/carousel.dart
index f89217b7dbb..712aecc3070 100644
--- a/animations/lib/src/misc/carousel.dart
+++ b/animations/lib/src/misc/carousel.dart
@@ -46,15 +46,15 @@ typedef OnCurrentItemChangedCallback = void Function(int currentItem);
 class Carousel extends StatefulWidget {
   final IndexedWidgetBuilder itemBuilder;
 
-  const Carousel({Key key, @required this.itemBuilder});
+  const Carousel({Key? key, required this.itemBuilder}) : super(key: key);
 
   @override
   _CarouselState createState() => _CarouselState();
 }
 
 class _CarouselState extends State<Carousel> {
-  PageController _controller;
-  int _currentPage;
+  late final PageController _controller;
+  late int _currentPage;
   bool _pageHasChanged = false;
 
   @override
@@ -81,11 +81,11 @@ class _CarouselState extends State<Carousel> {
       itemBuilder: (context, index) => AnimatedBuilder(
         animation: _controller,
         builder: (context, child) {
-          var result = _pageHasChanged ? _controller.page : _currentPage * 1.0;
+          var result = _pageHasChanged ? _controller.page! : _currentPage * 1.0;
 
           // The horizontal position of the page between a 1 and 0
           var value = result - index;
-          value = (1 - (value.abs() * .5)).clamp(0.0, 1.0) as double;
+          value = (1 - (value.abs() * .5)).clamp(0.0, 1.0);
 
           return Center(
             child: SizedBox(
diff --git a/animations/lib/src/misc/curved_animation.dart b/animations/lib/src/misc/curved_animation.dart
index 06558ebde89..52edbdebb68 100644
--- a/animations/lib/src/misc/curved_animation.dart
+++ b/animations/lib/src/misc/curved_animation.dart
@@ -15,14 +15,15 @@ class CurvedAnimationDemo extends StatefulWidget {
 class CurveChoice {
   final Curve curve;
   final String name;
-  const CurveChoice({this.curve, this.name});
+
+  const CurveChoice({required this.curve, required this.name});
 }
 
 class _CurvedAnimationDemoState extends State<CurvedAnimationDemo>
     with SingleTickerProviderStateMixin {
-  AnimationController controller;
-  Animation<double> animationRotation;
-  Animation<Offset> animationTranslation;
+  late final AnimationController controller;
+  late final Animation<double> animationRotation;
+  late final Animation<Offset> animationTranslation;
   static const _duration = Duration(seconds: 4);
   List<CurveChoice> curves = [
     CurveChoice(curve: Curves.bounceIn, name: 'Bounce In'),
@@ -38,8 +39,8 @@ class _CurvedAnimationDemoState extends State<CurvedAnimationDemo>
     CurveChoice(curve: Curves.easeInCirc, name: 'Ease In Circle'),
     CurveChoice(curve: Curves.easeOutCirc, name: 'Ease Out Circle'),
   ];
-  CurveChoice selectedForwardCurve, selectedReverseCurve;
-  CurvedAnimation curvedAnimation;
+  late CurveChoice selectedForwardCurve, selectedReverseCurve;
+  late final CurvedAnimation curvedAnimation;
 
   @override
   void initState() {
@@ -100,10 +101,12 @@ class _CurvedAnimationDemoState extends State<CurvedAnimationDemo>
                   value: curve, child: Text(curve.name));
             }).toList(),
             onChanged: (newCurve) {
-              setState(() {
-                selectedForwardCurve = newCurve;
-                curvedAnimation.curve = selectedForwardCurve.curve;
-              });
+              if (newCurve != null) {
+                setState(() {
+                  selectedForwardCurve = newCurve;
+                  curvedAnimation.curve = selectedForwardCurve.curve;
+                });
+              }
             },
             value: selectedForwardCurve,
           ),
@@ -118,10 +121,12 @@ class _CurvedAnimationDemoState extends State<CurvedAnimationDemo>
                   value: curve, child: Text(curve.name));
             }).toList(),
             onChanged: (newCurve) {
-              setState(() {
-                selectedReverseCurve = newCurve;
-                curvedAnimation.reverseCurve = selectedReverseCurve.curve;
-              });
+              if (newCurve != null) {
+                setState(() {
+                  selectedReverseCurve = newCurve;
+                  curvedAnimation.reverseCurve = selectedReverseCurve.curve;
+                });
+              }
             },
             value: selectedReverseCurve,
           ),
diff --git a/animations/lib/src/misc/hero_animation.dart b/animations/lib/src/misc/hero_animation.dart
index 8579cb2ff4f..fabac4cc4cc 100644
--- a/animations/lib/src/misc/hero_animation.dart
+++ b/animations/lib/src/misc/hero_animation.dart
@@ -18,7 +18,7 @@ class HeroAnimationDemo extends StatelessWidget {
           tag: 'hero-page-child',
           child: _createHeroContainer(
             size: 50.0,
-            color: Colors.grey[300],
+            color: Colors.grey.shade300,
           ),
         ),
         onTap: () => Navigator.of(context)
@@ -47,7 +47,10 @@ class HeroPage extends StatelessWidget {
   }
 }
 
-StatelessWidget _createHeroContainer({double size, Color color}) {
+StatelessWidget _createHeroContainer({
+  required double size,
+  required Color color,
+}) {
   return Container(
     height: size,
     width: size,
diff --git a/animations/lib/src/misc/physics_card_drag.dart b/animations/lib/src/misc/physics_card_drag.dart
index 99443a8a3b6..8edd1b29e16 100644
--- a/animations/lib/src/misc/physics_card_drag.dart
+++ b/animations/lib/src/misc/physics_card_drag.dart
@@ -27,7 +27,7 @@ class PhysicsCardDragDemo extends StatelessWidget {
 /// released.
 class DraggableCard extends StatefulWidget {
   final Widget child;
-  DraggableCard({this.child});
+  DraggableCard({required this.child});
 
   @override
   _DraggableCardState createState() => _DraggableCardState();
@@ -35,7 +35,7 @@ class DraggableCard extends StatefulWidget {
 
 class _DraggableCardState extends State<DraggableCard>
     with SingleTickerProviderStateMixin {
-  AnimationController _controller;
+  late final AnimationController _controller;
 
   /// The alignment of the card as it is dragged or being animated.
   ///
@@ -44,7 +44,7 @@ class _DraggableCardState extends State<DraggableCard>
   /// this value is set to the value of the [_animation].
   var _dragAlignment = Alignment.center;
 
-  Animation<Alignment> _animation;
+  late Animation<Alignment> _animation;
 
   final _spring = const SpringDescription(
     mass: 10,
diff --git a/animations/lib/src/misc/repeating_animation.dart b/animations/lib/src/misc/repeating_animation.dart
index f27fd73bb8e..31b3dda061f 100644
--- a/animations/lib/src/misc/repeating_animation.dart
+++ b/animations/lib/src/misc/repeating_animation.dart
@@ -13,8 +13,8 @@ class RepeatingAnimationDemo extends StatefulWidget {
 
 class RepeatingAnimationDemoState extends State<RepeatingAnimationDemo>
     with SingleTickerProviderStateMixin {
-  AnimationController _controller;
-  Animation<BorderRadius> _borderRadius;
+  late final AnimationController _controller;
+  late final Animation<BorderRadius> _borderRadius;
 
   @override
   void initState() {
diff --git a/animations/pubspec.lock b/animations/pubspec.lock
index 144924780fb..9ccea16347d 100644
--- a/animations/pubspec.lock
+++ b/animations/pubspec.lock
@@ -49,7 +49,7 @@ packages:
       name: cupertino_icons
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.0"
+    version: "1.0.2"
   fake_async:
     dependency: transitive
     description:
@@ -94,7 +94,7 @@ packages:
       name: pedantic
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.2"
+    version: "1.10.0"
   sky_engine:
     dependency: transitive
     description: flutter
diff --git a/animations/pubspec.yaml b/animations/pubspec.yaml
index c587d9a5a6f..b1449dc3f61 100644
--- a/animations/pubspec.yaml
+++ b/animations/pubspec.yaml
@@ -3,12 +3,12 @@ description: A new Flutter project.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.10.0 <3.0.0"
+  sdk: ">=2.12.0-0 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  cupertino_icons: ^1.0.0
+  cupertino_icons: ^1.0.2
 
 dev_dependencies:
   flutter_test: