Fix bounds calculation bug (#128)

.github/workflows/analyze-and-test.yaml

@@ -10,7 +10,7 @@ jobs:
     name: Flutter analyze
     strategy:
       matrix:
-        flutter: ['stable']
+        flutter: ['beta']
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v2

.github/workflows/publish-on-pub.yaml

@@ -10,12 +10,11 @@ jobs:
       - uses: actions/checkout@v2
       - uses: subosito/flutter-action@v1
         with:
-          channel: 'stable'
+          channel: 'beta'
       - run: flutter pub get
       - run: flutter pub run tool/publish/comment_dependency_overrides.dart
       - run: flutter pub get
-      - run: echo ::set-env name=RELEASE_VERSION::${GITHUB_REF}
-      - run: flutter pub run tool/publish/check_version.dart ${{ env.RELEASE_VERSION }}
+      - run: flutter pub run tool/publish/check_version.dart ${GITHUB_REF}
       - name: Setup credentials
         run: |
           mkdir -p $FLUTTER_HOME/.pub-cache

CHANGELOG.md

@@ -1,3 +1,13 @@
+## [0.8.0]
+- Migrate to null safety
+- Fix some rendering bugs
+
+## [0.7.1]
+- Fix a crash for some lottie file with empty paths.
+
+## [0.7.0+1]
+- Fix Flutter Web compilation error
+
 ## [0.7.0]
 - Performance improvement for complex animations.
 

README.md

@@ -8,7 +8,7 @@ animations exported as json with [Bodymovin](https://github.com/airbnb/lottie-we
 
 This repository is a unofficial conversion of the [Lottie-android](https://github.com/airbnb/lottie-android) library in pure Dart. 
 
-It works on Android, iOS and macOS and web.
+It works on Android, iOS, macOS, linux, windows and web.
 
 ## Usage
 
@@ -64,7 +64,7 @@ class MyApp extends StatefulWidget {
 }
 
 class _MyAppState extends State<MyApp> with TickerProviderStateMixin {
-  AnimationController _controller;
+  late final AnimationController _controller;
 
   @override
   void initState() {
@@ -137,7 +137,7 @@ class MyWidget extends StatefulWidget {
 }
 
 class _MyWidgetState extends State<MyWidget> {
-  Future<LottieComposition> _composition;
+  late final Future<LottieComposition> _composition;
 
   @override
   void initState() {
@@ -176,7 +176,7 @@ a specific position and size.
 class CustomDrawer extends StatelessWidget {
   final LottieComposition composition;
 
-  const CustomDrawer(this.composition, {Key key}) : super(key: key);
+  const CustomDrawer(this.composition, {Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {

README.template.md

@@ -8,7 +8,7 @@ animations exported as json with [Bodymovin](https://github.com/airbnb/lottie-we
 
 This repository is a unofficial conversion of the [Lottie-android](https://github.com/airbnb/lottie-android) library in pure Dart. 
 
-It works on Android, iOS and macOS and web.
+It works on Android, iOS, macOS, linux, windows and web.
 
 ## Usage
 

example/ios/Flutter/Debug.xcconfig

@@ -1,2 +1,3 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
 #include "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
 #include "Generated.xcconfig"

example/ios/Flutter/Release.xcconfig

@@ -1,2 +1,3 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
 #include "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
 #include "Generated.xcconfig"

example/lib/examples/alert_dialog.dart

@@ -23,7 +23,7 @@ class __PageState extends State<_Page> {
   void initState() {
     super.initState();
 
-    SchedulerBinding.instance.addPostFrameCallback((_) => _showLoader());
+    SchedulerBinding.instance!.addPostFrameCallback((_) => _showLoader());
   }
 
   void _showLoader() {

example/lib/examples/animate_no_repeat.dart

@@ -6,7 +6,7 @@ void main() async {
 }
 
 class App extends StatelessWidget {
-  const App({Key key}) : super(key: key);
+  const App({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {

example/lib/examples/animation_controller.dart

@@ -9,7 +9,7 @@ class MyApp extends StatefulWidget {
 }
 
 class _MyAppState extends State<MyApp> with TickerProviderStateMixin {
-  AnimationController _controller;
+  late final AnimationController _controller;
 
   @override
   void initState() {

example/lib/examples/animation_full_control.dart

@@ -17,7 +17,7 @@ class MyApp extends StatefulWidget {
 }
 
 class _MyAppState extends State<MyApp> with TickerProviderStateMixin {
-  AnimationController _controller;
+  late final AnimationController _controller;
 
   @override
   void initState() {
@@ -86,7 +86,7 @@ class _MyAppState extends State<MyApp> with TickerProviderStateMixin {
               ],
             ),
             const SizedBox(height: 30),
-            RaisedButton(
+            ElevatedButton(
               child: Text('Loop between frames'),
               onPressed: () {
                 // Loop between 2 specifics frames
@@ -97,7 +97,7 @@ class _MyAppState extends State<MyApp> with TickerProviderStateMixin {
                   min: start,
                   max: stop,
                   reverse: true,
-                  period: _controller.duration * (stop - start),
+                  period: _controller.duration! * (stop - start),
                 );
               },
             ),

example/lib/examples/custom_draw.dart

@@ -22,7 +22,7 @@ class MyWidget extends StatefulWidget {
 }
 
 class _MyWidgetState extends State<MyWidget> {
-  Future<LottieComposition> _composition;
+  late final Future<LottieComposition> _composition;
 
   @override
   void initState() {
@@ -57,7 +57,7 @@ class _MyWidgetState extends State<MyWidget> {
 class CustomDrawer extends StatelessWidget {
   final LottieComposition composition;
 
-  const CustomDrawer(this.composition, {Key key}) : super(key: key);
+  const CustomDrawer(this.composition, {Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {

example/lib/examples/custom_load.dart

@@ -23,7 +23,7 @@ class MyWidget extends StatefulWidget {
 }
 
 class _MyWidgetState extends State<MyWidget> {
-  Future<LottieComposition> _composition;
+  late final Future<LottieComposition> _composition;
 
   @override
   void initState() {

example/lib/examples/dynamic_properties.dart

@@ -8,7 +8,7 @@ void main() async {
 }
 
 class App extends StatefulWidget {
-  const App({Key key}) : super(key: key);
+  const App({Key? key}) : super(key: key);
 
   @override
   _AppState createState() => _AppState();
@@ -50,7 +50,7 @@ class _AppState extends State<App> with TickerProviderStateMixin {
               value: _useDelegates,
               onChanged: (newValue) {
                 setState(() {
-                  _useDelegates = newValue;
+                  _useDelegates = newValue!;
                 });
               },
             ),

example/lib/examples/dynamic_text.dart

@@ -7,14 +7,14 @@ void main() async {
 }
 
 class App extends StatefulWidget {
-  const App({Key key}) : super(key: key);
+  const App({Key? key}) : super(key: key);
 
   @override
   _AppState createState() => _AppState();
 }
 
 class _AppState extends State<App> with TickerProviderStateMixin {
-  TextEditingController _textController;
+  late final TextEditingController _textController;
 
   @override
   void initState() {

example/lib/examples/hide_after_complete.dart

@@ -6,14 +6,14 @@ void main() async {
 }
 
 class App extends StatefulWidget {
-  const App({Key key}) : super(key: key);
+  const App({Key? key}) : super(key: key);
 
   @override
   _AppState createState() => _AppState();
 }
 
 class _AppState extends State<App> with TickerProviderStateMixin {
-  AnimationController _animationController;
+  late final AnimationController _animationController;
   bool _showAnimation = true;
 
   @override

example/lib/examples/markers.dart

@@ -9,14 +9,14 @@ void main() async {
 }
 
 class App extends StatefulWidget {
-  const App({Key key}) : super(key: key);
+  const App({Key? key}) : super(key: key);
 
   @override
   _AppState createState() => _AppState();
 }
 
 class _AppState extends State<App> with TickerProviderStateMixin {
-  Future<LottieComposition> _composition;
+  late final Future<LottieComposition> _composition;
 
   @override
   void initState() {
@@ -35,9 +35,9 @@ class _AppState extends State<App> with TickerProviderStateMixin {
         body: FutureBuilder<LottieComposition>(
           future: _composition,
           builder: (context, snapshot) {
-            if (snapshot.hasError) return ErrorWidget(snapshot.error);
+            if (snapshot.hasError) return ErrorWidget(snapshot.error!);
             if (!snapshot.hasData) return CircularProgressIndicator();
-            return _LottieDetails(snapshot.data);
+            return _LottieDetails(snapshot.data!);
           },
         ),
       ),
@@ -48,7 +48,7 @@ class _AppState extends State<App> with TickerProviderStateMixin {
 class _LottieDetails extends StatefulWidget {
   final LottieComposition composition;
 
-  const _LottieDetails(this.composition, {Key key}) : super(key: key);
+  const _LottieDetails(this.composition, {Key? key}) : super(key: key);
 
   @override
   _LottieDetailsState createState() => _LottieDetailsState();
@@ -56,7 +56,7 @@ class _LottieDetails extends StatefulWidget {
 
 class _LottieDetailsState extends State<_LottieDetails>
     with TickerProviderStateMixin {
-  AnimationController _controller;
+  late final AnimationController _controller;
 
   @override
   void initState() {
@@ -87,15 +87,15 @@ class _LottieDetailsState extends State<_LottieDetails>
           title: Text('Composition duration'),
           trailing: Text(widget.composition.durationFrames.toStringAsFixed(1)),
         ),
-        RaisedButton(
+        ElevatedButton(
           child: Text('touchDownEnd - touchUpCancel'),
           onPressed: () => _playBetween('touchDownEnd', 'touchUpCancel'),
         ),
-        RaisedButton(
+        ElevatedButton(
           child: Text('touchDownStart - touchDownEnd'),
           onPressed: () => _playBetween('touchDownStart', 'touchDownEnd'),
         ),
-        RaisedButton(
+        ElevatedButton(
           child: Text('touchDownEnd - touchUpEnd'),
           onPressed: () => _playBetween('touchDownEnd', 'touchUpEnd'),
         ),
@@ -112,8 +112,8 @@ class _LottieDetailsState extends State<_LottieDetails>
   }
 
   void _playBetween(String marker1, String marker2) {
-    var start = widget.composition.getMarker(marker1).start;
-    var end = widget.composition.getMarker(marker2).start;
+    var start = widget.composition.getMarker(marker1)!.start;
+    var end = widget.composition.getMarker(marker2)!.start;
 
     _controller.value = start;
     _controller.animateTo(end,

example/lib/examples/repeat.dart

@@ -0,0 +1,63 @@
+import 'package:flutter/material.dart';
+import 'package:lottie/lottie.dart';
+
+void main() => runApp(MyApp());
+
+class MyApp extends StatefulWidget {
+  @override
+  _MyAppState createState() => _MyAppState();
+}
+
+class _MyAppState extends State<MyApp> with TickerProviderStateMixin {
+  late final AnimationController _controller;
+  int _repeatIndex = 0;
+
+  @override
+  void initState() {
+    super.initState();
+
+    _controller = AnimationController(vsync: this)
+      ..addStatusListener((status) {
+        if (status == AnimationStatus.completed) {
+          setState(() {
+            _repeatIndex++;
+          });
+          if (_repeatIndex < 5) {
+            _controller.reset();
+            _controller.forward();
+          }
+        }
+      });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      home: Scaffold(
+        body: ListView(
+          children: [
+            Lottie.asset(
+              'assets/AndroidWave.json',
+              controller: _controller,
+              width: 150,
+              height: 150,
+              onLoaded: (composition) {
+                // Configure the AnimationController with the duration of the
+                // Lottie file and start the animation.
+                _controller.duration = composition.duration;
+                _controller.forward();
+              },
+            ),
+            Center(child: Text('Repeat: $_repeatIndex')),
+          ],
+        ),
+      ),
+    );
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+}

example/lib/examples/run_once.dart

@@ -12,7 +12,7 @@ void main() async {
 }
 
 class App extends StatefulWidget {
-  const App({Key key}) : super(key: key);
+  const App({Key? key}) : super(key: key);
 
   @override
   _AppState createState() => _AppState();
@@ -20,7 +20,7 @@ class App extends StatefulWidget {
 
 class _AppState extends State<App> with TickerProviderStateMixin {
   int _index = 0;
-  AnimationController _animationController;
+  late final AnimationController _animationController;
 
   @override
   void initState() {

example/lib/examples/save_frames.dart

@@ -1,3 +1,5 @@
+//@dart=2.10
+
 import 'dart:io';
 import 'dart:ui';
 import 'package:flutter/material.dart';
@@ -26,7 +28,7 @@ class _MyAppState extends State<MyApp> {
           child: Column(
             crossAxisAlignment: CrossAxisAlignment.stretch,
             children: [
-              RaisedButton(
+              ElevatedButton(
                 child: Text('Export all frames'),
                 onPressed: _export,
               ),

example/lib/main_app.dart

@@ -42,8 +42,10 @@ class App extends StatelessWidget {
                 ),
               ),
               onTap: () {
-                Navigator.of(context).push(MaterialPageRoute<void>(
-                    builder: (context) => Detail(assetName)));
+                Navigator.push(
+                    context,
+                    MaterialPageRoute<void>(
+                        builder: (context) => Detail(assetName)));
               },
             );
           },
@@ -56,7 +58,7 @@ class App extends StatelessWidget {
 class _Item extends StatelessWidget {
   final Widget child;
 
-  const _Item({Key key, this.child}) : super(key: key);
+  const _Item({Key? key, required this.child}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -81,26 +83,18 @@ class _Item extends StatelessWidget {
 class Detail extends StatefulWidget {
   final String assetName;
 
-  const Detail(this.assetName, {Key key}) : super(key: key);
+  const Detail(this.assetName, {Key? key}) : super(key: key);
 
   @override
   _DetailState createState() => _DetailState();
 }
 
 class _DetailState extends State<Detail> with TickerProviderStateMixin {
-  AnimationController _controller;
-
-  @override
-  void initState() {
-    super.initState();
-
-    _controller = AnimationController(vsync: this);
-  }
+  late final _controller = AnimationController(vsync: this);
 
   @override
   void dispose() {
     _controller.dispose();
-
     super.dispose();
   }
 

example/lib/sizing_example.dart

@@ -13,7 +13,7 @@ void main() async {
 class App extends StatelessWidget {
   final LottieComposition composition;
 
-  const App({Key key, this.composition}) : super(key: key);
+  const App({Key? key, required this.composition}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -97,13 +97,13 @@ class App extends StatelessWidget {
 
 class _Lottie extends StatefulWidget {
   final LottieComposition composition;
-  final double width;
-  final double height;
-  final BoxFit fit;
-  final AlignmentGeometry alignment;
+  final double? width;
+  final double? height;
+  final BoxFit? fit;
+  final AlignmentGeometry? alignment;
 
   const _Lottie(this.composition,
-      {Key key, this.width, this.height, this.fit, this.alignment})
+      {Key? key, this.width, this.height, this.fit, this.alignment})
       : super(key: key);
 
   @override
@@ -111,7 +111,7 @@ class _Lottie extends StatefulWidget {
 }
 
 class __LottieState extends State<_Lottie> with TickerProviderStateMixin {
-  AnimationController _controller;
+  late AnimationController _controller;
 
   @override
   void initState() {

example/lib/tests/airbnb.dart

@@ -6,7 +6,7 @@ void main() async {
 }
 
 class App extends StatelessWidget {
-  const App({Key key}) : super(key: key);
+  const App({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {

example/lib/tests/we_accept.dart

@@ -6,7 +6,7 @@ void main() async {
 }
 
 class App extends StatelessWidget {
-  const App({Key key}) : super(key: key);
+  const App({Key? key}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {

example/macos/Flutter/Flutter-Debug.xcconfig

@@ -1,2 +1,3 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
 #include "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
 #include "ephemeral/Flutter-Generated.xcconfig"

example/macos/Flutter/Flutter-Release.xcconfig

@@ -1,2 +1,3 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
 #include "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
 #include "ephemeral/Flutter-Generated.xcconfig"

example/macos/Podfile.lock

@@ -1,27 +1,28 @@
 PODS:
-  - FlutterMacOS (1.0.0)
+  - FlutterMacOS (1.22.4)
   - path_provider (0.0.1)
   - path_provider_macos (0.0.1):
     - FlutterMacOS
 
 DEPENDENCIES:
-  - FlutterMacOS (from `Flutter/ephemeral/.symlinks/flutter/darwin-x64-profile`)
   - path_provider (from `Flutter/ephemeral/.symlinks/plugins/path_provider/macos`)
   - path_provider_macos (from `Flutter/ephemeral/.symlinks/plugins/path_provider_macos/macos`)
 
+SPEC REPOS:
+  trunk:
+    - FlutterMacOS
+
 EXTERNAL SOURCES:
-  FlutterMacOS:
-    :path: Flutter/ephemeral/.symlinks/flutter/darwin-x64-profile
   path_provider:
     :path: Flutter/ephemeral/.symlinks/plugins/path_provider/macos
   path_provider_macos:
     :path: Flutter/ephemeral/.symlinks/plugins/path_provider_macos/macos
 
 SPEC CHECKSUMS:
-  FlutterMacOS: 15bea8a44d2fa024068daa0140371c020b4b6ff9
+  FlutterMacOS: ac210ef71944b3f04789076d70d4c72c7ec0c619
   path_provider: e0848572d1d38b9a7dd099e79cf83f5b7e2cde9f
   path_provider_macos: a0a3fd666cb7cd0448e936fb4abad4052961002b
 
 PODFILE CHECKSUM: d8ba9b3e9e93c62c74a660b46c6fcb09f03991a7
 
-COCOAPODS: 1.9.1
+COCOAPODS: 1.10.1

example/macos/Runner.xcodeproj/project.pbxproj

@@ -26,10 +26,6 @@
 		33CC10F32044A3C60003C045 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 33CC10F22044A3C60003C045 /* Assets.xcassets */; };
 		33CC10F62044A3C60003C045 /* MainMenu.xib in Resources */ = {isa = PBXBuildFile; fileRef = 33CC10F42044A3C60003C045 /* MainMenu.xib */; };
 		33CC11132044BFA00003C045 /* MainFlutterWindow.swift in Sources */ = {isa = PBXBuildFile; fileRef = 33CC11122044BFA00003C045 /* MainFlutterWindow.swift */; };
-		33D1A10422148B71006C7A3E /* FlutterMacOS.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 33D1A10322148B71006C7A3E /* FlutterMacOS.framework */; };
-		33D1A10522148B93006C7A3E /* FlutterMacOS.framework in Bundle Framework */ = {isa = PBXBuildFile; fileRef = 33D1A10322148B71006C7A3E /* FlutterMacOS.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
-		D73912F022F37F9E000D13A0 /* App.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = D73912EF22F37F9E000D13A0 /* App.framework */; };
-		D73912F222F3801D000D13A0 /* App.framework in Bundle Framework */ = {isa = PBXBuildFile; fileRef = D73912EF22F37F9E000D13A0 /* App.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		F03CC91740A974D36C2A6384 /* Pods_Runner.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 0BC6FF5FCD90624533CC60DB /* Pods_Runner.framework */; };
 /* End PBXBuildFile section */
 
@@ -50,8 +46,6 @@
 			dstPath = "";
 			dstSubfolderSpec = 10;
 			files = (
-				D73912F222F3801D000D13A0 /* App.framework in Bundle Framework */,
-				33D1A10522148B93006C7A3E /* FlutterMacOS.framework in Bundle Framework */,
 			);
 			name = "Bundle Framework";
 			runOnlyForDeploymentPostprocessing = 0;
@@ -73,14 +67,12 @@
 		33CEB47222A05771004F2AC0 /* Flutter-Debug.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = "Flutter-Debug.xcconfig"; sourceTree = "<group>"; };
 		33CEB47422A05771004F2AC0 /* Flutter-Release.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = "Flutter-Release.xcconfig"; sourceTree = "<group>"; };
 		33CEB47722A0578A004F2AC0 /* Flutter-Generated.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; name = "Flutter-Generated.xcconfig"; path = "ephemeral/Flutter-Generated.xcconfig"; sourceTree = "<group>"; };
-		33D1A10322148B71006C7A3E /* FlutterMacOS.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = FlutterMacOS.framework; path = Flutter/ephemeral/FlutterMacOS.framework; sourceTree = SOURCE_ROOT; };
 		33E51913231747F40026EE4D /* DebugProfile.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; path = DebugProfile.entitlements; sourceTree = "<group>"; };
 		33E51914231749380026EE4D /* Release.entitlements */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.entitlements; path = Release.entitlements; sourceTree = "<group>"; };
 		33E5194F232828860026EE4D /* AppInfo.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = AppInfo.xcconfig; sourceTree = "<group>"; };
 		5B4C0E87024EC2686CA05E23 /* Pods-Runner.profile.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Runner.profile.xcconfig"; path = "Target Support Files/Pods-Runner/Pods-Runner.profile.xcconfig"; sourceTree = "<group>"; };
 		7AFA3C8E1D35360C0083082E /* Release.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = Release.xcconfig; sourceTree = "<group>"; };
 		9740EEB21CF90195004384FC /* Debug.xcconfig */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xcconfig; path = Debug.xcconfig; sourceTree = "<group>"; };
-		D73912EF22F37F9E000D13A0 /* App.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = App.framework; path = Flutter/ephemeral/App.framework; sourceTree = SOURCE_ROOT; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -88,8 +80,6 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				D73912F022F37F9E000D13A0 /* App.framework in Frameworks */,
-				33D1A10422148B71006C7A3E /* FlutterMacOS.framework in Frameworks */,
 				F03CC91740A974D36C2A6384 /* Pods_Runner.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -145,8 +135,6 @@
 				33CEB47222A05771004F2AC0 /* Flutter-Debug.xcconfig */,
 				33CEB47422A05771004F2AC0 /* Flutter-Release.xcconfig */,
 				33CEB47722A0578A004F2AC0 /* Flutter-Generated.xcconfig */,
-				D73912EF22F37F9E000D13A0 /* App.framework */,
-				33D1A10322148B71006C7A3E /* FlutterMacOS.framework */,
 			);
 			path = Flutter;
 			sourceTree = "<group>";
@@ -281,7 +269,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "echo \"$PRODUCT_NAME.app\" > \"$PROJECT_DIR\"/Flutter/ephemeral/.app_filename\n";
+			shellScript = "echo \"$PRODUCT_NAME.app\" > \"$PROJECT_DIR\"/Flutter/ephemeral/.app_filename && \"$FLUTTER_ROOT\"/packages/flutter_tools/bin/macos_assemble.sh embed\n";
 		};
 		33CC111E2044C6BF0003C045 /* ShellScript */ = {
 			isa = PBXShellScriptBuildPhase;
@@ -330,10 +318,10 @@
 			buildActionMask = 2147483647;
 			files = (
 			);
-			inputFileListPaths = (
+			inputPaths = (
 			);
 			name = "[CP] Embed Pods Frameworks";
-			outputFileListPaths = (
+			outputPaths = (
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;

example/pubspec.lock

@@ -7,77 +7,63 @@ packages:
       name: archive
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.13"
-  args:
-    dependency: transitive
-    description:
-      name: args
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.6.0"
+    version: "3.0.0-nullsafety.0"
   async:
     dependency: transitive
     description:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.5.0-nullsafety.1"
+    version: "2.5.0-nullsafety.3"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0-nullsafety.3"
   characters:
     dependency: transitive
     description:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.3"
+    version: "1.1.0-nullsafety.5"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0-nullsafety.3"
   clock:
     dependency: transitive
     description:
       name: clock
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0-nullsafety.3"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.15.0-nullsafety.3"
-  convert:
-    dependency: transitive
-    description:
-      name: convert
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.1"
+    version: "1.15.0-nullsafety.5"
   crypto:
     dependency: transitive
     description:
       name: crypto
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.5"
+    version: "3.0.0-nullsafety.0"
   fake_async:
     dependency: transitive
     description:
       name: fake_async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0-nullsafety.3"
   ffi:
     dependency: transitive
     description:
@@ -103,7 +89,7 @@ packages:
       name: flutter_colorpicker
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.4"
+    version: "0.4.0-nullsafety.0"
   flutter_test:
     dependency: "direct dev"
     description: flutter
@@ -115,7 +101,7 @@ packages:
       name: golden_toolkit
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.6.0"
+    version: "0.9.0-nullsafety.0"
   http:
     dependency: "direct main"
     description:
@@ -143,42 +129,42 @@ packages:
       name: logging
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.11.4"
+    version: "1.0.0-nullsafety.0"
   lottie:
     dependency: "direct main"
     description:
       path: ".."
       relative: true
     source: path
-    version: "0.7.0"
+    version: "0.8.0-nullsafety.0"
   matcher:
     dependency: transitive
     description:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.10-nullsafety.1"
+    version: "0.12.10-nullsafety.3"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0-nullsafety.6"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.1"
+    version: "1.8.0-nullsafety.3"
   path_provider:
     dependency: "direct main"
     description:
       name: path_provider
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.21"
+    version: "1.6.27"
   path_provider_linux:
     dependency: transitive
     description:
@@ -192,21 +178,21 @@ packages:
       name: path_provider_macos
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.0.4+4"
+    version: "0.0.4+8"
   path_provider_platform_interface:
     dependency: transitive
     description:
       name: path_provider_platform_interface
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.3"
+    version: "1.0.4"
   path_provider_windows:
     dependency: transitive
     description:
       name: path_provider_windows
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.0.4+1"
+    version: "0.0.4+3"
   pedantic:
     dependency: transitive
     description:
@@ -246,63 +232,63 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.2"
+    version: "1.8.0-nullsafety.4"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.10.0-nullsafety.1"
+    version: "1.10.0-nullsafety.6"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0-nullsafety.3"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0-nullsafety.3"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0-nullsafety.3"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19-nullsafety.2"
+    version: "0.2.19-nullsafety.6"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0-nullsafety.5"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.3"
+    version: "2.1.0-nullsafety.5"
   win32:
     dependency: transitive
     description:
       name: win32
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.7.3"
+    version: "1.7.4"
   xdg_directories:
     dependency: transitive
     description:
@@ -311,5 +297,5 @@ packages:
     source: hosted
     version: "0.1.2"
 sdks:
-  dart: ">=2.10.0-110 <2.11.0"
-  flutter: ">=1.12.13+hotfix.5 <2.0.0"
+  dart: ">=2.12.0-29.10.beta <3.0.0"
+  flutter: ">=1.24.0-10.2.pre"

example/pubspec.yaml

@@ -1,14 +1,14 @@
 name: lottie_example
 description: A sample app for the Lottie player
-version: 0.0.1
+publish_to: none
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0-0 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  flutter_colorpicker:
+  flutter_colorpicker: ^0.4.0-nullsafety.0
   http:
   lottie:
     path: ../
@@ -17,7 +17,7 @@ dependencies:
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  golden_toolkit:
+  golden_toolkit: ^0.9.0-nullsafety.0
 
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec
@@ -31,6 +31,7 @@ flutter:
     - assets/lottiefiles/
     - assets/Mobilo/
     - assets/Tests/
+    - assets/Tests/images/
     - assets/Logo/
     - assets/Images/
     - assets/Images/WeAccept/

example/test/dynamic_properties_test.dart

@@ -7,7 +7,7 @@ import 'package:lottie/lottie.dart';
 import 'utils.dart';
 
 void main() {
-  LottieComposition composition;
+  late LottieComposition composition;
 
   setUpAll(() async {
     composition = await LottieComposition.fromBytes(
@@ -15,7 +15,7 @@ void main() {
   });
 
   void testGolden(String description, ValueDelegate delegate,
-      {double progress}) async {
+      {double? progress}) async {
     var screenshotName = description
         .toLowerCase()
         .replaceAll(RegExp('[^a-z0-9 ]'), '')
@@ -288,8 +288,8 @@ void main() {
     testGolden(
         'Opacity interpolation ($progress)',
         ValueDelegate.transformOpacity(['Shape Layer 1', 'Rectangle'],
-            callback: (frameInfo) => lerpDouble(
-                    10, 100, Curves.linear.transform(frameInfo.overallProgress))
+            callback: (frameInfo) => lerpDouble(10, 100,
+                    Curves.linear.transform(frameInfo.overallProgress))!
                 .round()),
         progress: progress);
   }

example/test/flutter_test_config.dart

@@ -1,7 +1,7 @@
 import 'dart:async';
 import 'package:golden_toolkit/golden_toolkit.dart';
 
-Future<void> main(FutureOr<void> Function() testMain) async {
+Future<void> testExecutable(FutureOr<void> Function() testMain) async {
   await loadAppFonts();
   return testMain();
 }

example/test/golden_test.dart

@@ -16,7 +16,8 @@ void main() {
       var size = Size(500, 400);
       tester.binding.window.physicalSizeTestValue = size;
       tester.binding.window.devicePixelRatioTestValue = 1.0;
-      var composition = await tester.runAsync(() => FileLottie(asset).load());
+      var composition =
+          (await tester.runAsync(() => FileLottie(asset).load()))!;
 
       await tester.pumpWidget(FilmStrip(composition, size: size));
 

example/test/utils.dart

@@ -3,11 +3,11 @@ import 'package:lottie/lottie.dart';
 
 class FilmStrip extends StatelessWidget {
   final LottieComposition composition;
-  final LottieDelegates delegates;
+  final LottieDelegates? delegates;
   final Size size;
 
   const FilmStrip(this.composition,
-      {Key key, @required this.size, this.delegates})
+      {Key? key, required this.size, this.delegates})
       : super(key: key);
 
   @override

lib/src/animation/content/base_stroke_content.dart

@@ -34,21 +34,20 @@ abstract class BaseStrokeContent
   final List<double> _dashPatternValues;
   final Paint paint = Paint()..style = PaintingStyle.stroke;
 
-  final BaseKeyframeAnimation<dynamic, double> _widthAnimation;
-  final BaseKeyframeAnimation<dynamic, int> _opacityAnimation;
-  final List<BaseKeyframeAnimation<dynamic, double>> _dashPatternAnimations;
-  final BaseKeyframeAnimation<dynamic,
-      double> /*?*/ _dashPatternOffsetAnimation;
-  BaseKeyframeAnimation<ColorFilter, ColorFilter> /*?*/ _colorFilterAnimation;
+  final BaseKeyframeAnimation<Object, double> _widthAnimation;
+  final BaseKeyframeAnimation<Object, int> _opacityAnimation;
+  final List<BaseKeyframeAnimation<Object, double>> _dashPatternAnimations;
+  final BaseKeyframeAnimation<Object, double>? _dashPatternOffsetAnimation;
+  BaseKeyframeAnimation<ColorFilter, ColorFilter?>? _colorFilterAnimation;
 
   BaseStrokeContent(this.lottieDrawable, this.layer,
-      {StrokeCap cap,
-      StrokeJoin join,
-      double miterLimit,
-      AnimatableIntegerValue opacity,
-      AnimatableDoubleValue width,
-      List<AnimatableDoubleValue> dashPattern,
-      AnimatableDoubleValue dashOffset})
+      {required StrokeCap cap,
+      required StrokeJoin join,
+      required double miterLimit,
+      required AnimatableIntegerValue opacity,
+      required AnimatableDoubleValue width,
+      required List<AnimatableDoubleValue> dashPattern,
+      AnimatableDoubleValue? dashOffset})
       : _widthAnimation = width.createAnimation(),
         _opacityAnimation = opacity.createAnimation(),
         _dashPatternOffsetAnimation = dashOffset?.createAnimation(),
@@ -76,7 +75,7 @@ abstract class BaseStrokeContent
       _dashPatternAnimations[i].addUpdateListener(onUpdateListener);
     }
     if (_dashPatternOffsetAnimation != null) {
-      _dashPatternOffsetAnimation.addUpdateListener(onUpdateListener);
+      _dashPatternOffsetAnimation!.addUpdateListener(onUpdateListener);
     }
   }
 
@@ -86,7 +85,7 @@ abstract class BaseStrokeContent
 
   @override
   void setContents(List<Content> contentsBefore, List<Content> contentsAfter) {
-    TrimPathContent trimPathContentBefore;
+    TrimPathContent? trimPathContentBefore;
     for (var i = contentsBefore.length - 1; i >= 0; i--) {
       var content = contentsBefore[i];
       if (content is TrimPathContent &&
@@ -98,7 +97,7 @@ abstract class BaseStrokeContent
       trimPathContentBefore.addListener(onUpdateListener);
     }
 
-    _PathGroup currentPathGroup;
+    _PathGroup? currentPathGroup;
     for (var i = contentsAfter.length - 1; i >= 0; i--) {
       var content = contentsAfter[i];
       if (content is TrimPathContent &&
@@ -119,7 +118,8 @@ abstract class BaseStrokeContent
   }
 
   @override
-  void draw(Canvas canvas, Size size, Matrix4 parentMatrix, {int parentAlpha}) {
+  void draw(Canvas canvas, Size size, Matrix4 parentMatrix,
+      {required int parentAlpha}) {
     L.beginSection('StrokeContent#draw');
     if (parentMatrix.hasZeroScaleAxis) {
       L.endSection('StrokeContent#draw');
@@ -136,7 +136,7 @@ abstract class BaseStrokeContent
     }
 
     if (_colorFilterAnimation != null) {
-      paint.colorFilter = _colorFilterAnimation.value;
+      paint.colorFilter = _colorFilterAnimation!.value;
     }
 
     for (var i = 0; i < _pathGroups.length; i++) {
@@ -175,18 +175,17 @@ abstract class BaseStrokeContent
     var pathMetrics = _path.computeMetrics().toList();
     var totalLength = pathMetrics.fold<double>(0.0, (a, b) => a + b.length);
 
-    var offsetLength = totalLength * pathGroup.trimPath.offset.value / 360.0;
-    var startLength =
-        totalLength * pathGroup.trimPath.start.value / 100.0 + offsetLength;
-    var endLength =
-        totalLength * pathGroup.trimPath.end.value / 100.0 + offsetLength;
+    var trimPath = pathGroup.trimPath!;
+    var offsetLength = totalLength * trimPath.offset.value / 360.0;
+    var startLength = totalLength * trimPath.start.value / 100.0 + offsetLength;
+    var endLength = totalLength * trimPath.end.value / 100.0 + offsetLength;
 
     var currentLength = 0.0;
     for (var j = pathGroup.paths.length - 1; j >= 0; j--) {
       _trimPathPath
           .set(pathGroup.paths[j].getPath().transform(parentMatrix.storage));
       var pathMetrics = _trimPathPath.computeMetrics().toList();
-      var length = pathMetrics.first.length;
+      var length = pathMetrics.isNotEmpty ? pathMetrics.first.length : 0;
       if (endLength > totalLength &&
           endLength - totalLength < currentLength + length &&
           currentLength < endLength - totalLength) {
@@ -229,7 +228,7 @@ abstract class BaseStrokeContent
   }
 
   @override
-  Rect getBounds(Matrix4 parentMatrix, {bool applyParents}) {
+  Rect getBounds(Matrix4 parentMatrix, {required bool applyParents}) {
     L.beginSection('StrokeContent#getBounds');
     _path.reset();
     for (var i = 0; i < _pathGroups.length; i++) {
@@ -242,11 +241,10 @@ abstract class BaseStrokeContent
     var bounds = _path.getBounds();
 
     var width = _widthAnimation.value;
-    bounds = Rect.fromLTWH(bounds.left - width / 2.0, bounds.top - width / 2.0,
+    bounds = Rect.fromLTRB(bounds.left - width / 2.0, bounds.top - width / 2.0,
         bounds.right + width / 2.0, bounds.bottom + width / 2.0);
     // Add padding to account for rounding errors.
-    bounds = Rect.fromLTWH(
-        bounds.left - 1, bounds.top - 1, bounds.right + 1, bounds.bottom + 1);
+    bounds = bounds.inflate(1);
     L.endSection('StrokeContent#getBounds');
     return bounds;
   }
@@ -279,7 +277,7 @@ abstract class BaseStrokeContent
 
     var offset = _dashPatternOffsetAnimation == null
         ? 0.0
-        : _dashPatternOffsetAnimation.value * scale;
+        : _dashPatternOffsetAnimation!.value * scale;
     var newPath = dashPath(path, intervals: _dashPatternValues, phase: offset);
     L.endSection('StrokeContent#applyDashPattern');
 
@@ -295,7 +293,7 @@ abstract class BaseStrokeContent
 
   @override
   @mustCallSuper
-  void addValueCallback<T>(T property, LottieValueCallback<T> /*?*/ callback) {
+  void addValueCallback<T>(T property, LottieValueCallback<T>? callback) {
     if (property == LottieProperty.opacity) {
       _opacityAnimation.setValueCallback(callback as LottieValueCallback<int>);
     } else if (property == LottieProperty.strokeWidth) {
@@ -309,9 +307,9 @@ abstract class BaseStrokeContent
         _colorFilterAnimation = null;
       } else {
         _colorFilterAnimation =
-            ValueCallbackKeyframeAnimation<ColorFilter, ColorFilter>(
-                callback as LottieValueCallback<ColorFilter>);
-        _colorFilterAnimation.addUpdateListener(onUpdateListener);
+            ValueCallbackKeyframeAnimation<ColorFilter, ColorFilter?>(
+                callback as LottieValueCallback<ColorFilter>, null);
+        _colorFilterAnimation!.addUpdateListener(onUpdateListener);
         layer.addAnimation(_colorFilterAnimation);
       }
     }
@@ -321,7 +319,7 @@ abstract class BaseStrokeContent
 /// Data class to help drawing trim paths individually.
 class _PathGroup {
   final List<PathContent> paths = <PathContent>[];
-  final TrimPathContent /*?*/ trimPath;
+  final TrimPathContent? trimPath;
 
   _PathGroup(this.trimPath);
 }

lib/src/animation/content/content.dart

@@ -1,5 +1,5 @@
 abstract class Content {
-  String get name;
+  String? get name;
 
   void setContents(List<Content> contentsBefore, List<Content> contentsAfter);
 }

lib/src/animation/content/content_group.dart

@@ -1,5 +1,4 @@
 import 'dart:ui';
-import 'package:meta/meta.dart';
 import 'package:vector_math/vector_math_64.dart';
 import '../../lottie_drawable.dart';
 import '../../model/animatable/animatable_transform.dart';
@@ -32,8 +31,7 @@ class ContentGroup implements DrawingContent, PathContent, KeyPathElement {
     return contents;
   }
 
-  static AnimatableTransform /*?*/ findTransform(
-      List<ContentModel> contentModels) {
+  static AnimatableTransform? findTransform(List<ContentModel> contentModels) {
     for (var i = 0; i < contentModels.length; i++) {
       var contentModel = contentModels[i];
       if (contentModel is AnimatableTransform) {
@@ -47,12 +45,12 @@ class ContentGroup implements DrawingContent, PathContent, KeyPathElement {
   final Path _path = PathFactory.create();
 
   @override
-  final String name;
+  final String? name;
   final bool _hidden;
   final List<Content> _contents;
   final LottieDrawable _lottieDrawable;
-  List<PathContent> /*?*/ _pathContents;
-  TransformKeyframeAnimation /*?*/ _transformAnimation;
+  List<PathContent>? _pathContents;
+  TransformKeyframeAnimation? _transformAnimation;
 
   ContentGroup(final LottieDrawable lottieDrawable, BaseLayer layer,
       ShapeGroup shapeGroup)
@@ -65,11 +63,11 @@ class ContentGroup implements DrawingContent, PathContent, KeyPathElement {
             findTransform(shapeGroup.items));
 
   ContentGroup.copy(this._lottieDrawable, BaseLayer layer, this.name,
-      this._hidden, this._contents, AnimatableTransform /*?*/ transform) {
+      this._hidden, this._contents, AnimatableTransform? transform) {
     if (transform != null) {
-      _transformAnimation = transform.createAnimation();
-      _transformAnimation.addAnimationsToLayer(layer);
-      _transformAnimation.addListener(onValueChanged);
+      _transformAnimation = transform.createAnimation()
+        ..addAnimationsToLayer(layer)
+        ..addListener(onValueChanged);
     }
 
     var greedyContents = <GreedyContent>[];
@@ -104,20 +102,20 @@ class ContentGroup implements DrawingContent, PathContent, KeyPathElement {
 
   List<PathContent> getPathList() {
     if (_pathContents == null) {
-      _pathContents = <PathContent>[];
+      var pathContents = _pathContents = <PathContent>[];
       for (var i = 0; i < _contents.length; i++) {
         var content = _contents[i];
         if (content is PathContent) {
-          _pathContents.add(content);
+          pathContents.add(content);
         }
       }
     }
-    return _pathContents;
+    return _pathContents!;
   }
 
   Matrix4 getTransformationMatrix() {
     if (_transformAnimation != null) {
-      return _transformAnimation.getMatrix();
+      return _transformAnimation!.getMatrix();
     }
     _matrix.reset();
     return _matrix;
@@ -128,7 +126,7 @@ class ContentGroup implements DrawingContent, PathContent, KeyPathElement {
     // TODO: cache this somehow.
     _matrix.reset();
     if (_transformAnimation != null) {
-      _matrix.set(_transformAnimation.getMatrix());
+      _matrix.set(_transformAnimation!.getMatrix());
     }
     _path.reset();
     if (_hidden) {
@@ -145,17 +143,17 @@ class ContentGroup implements DrawingContent, PathContent, KeyPathElement {
 
   @override
   void draw(Canvas canvas, Size size, Matrix4 parentMatrix,
-      {@required int parentAlpha}) {
+      {required int parentAlpha}) {
     if (_hidden) {
       return;
     }
     _matrix.set(parentMatrix);
     int layerAlpha;
     if (_transformAnimation != null) {
-      _matrix.preConcat(_transformAnimation.getMatrix());
-      var opacity = _transformAnimation.opacity == null
+      _matrix.preConcat(_transformAnimation!.getMatrix());
+      var opacity = _transformAnimation?.opacity == null
           ? 100
-          : _transformAnimation.opacity.value;
+          : _transformAnimation!.opacity!.value;
       layerAlpha = ((opacity / 100.0 * parentAlpha / 255.0) * 255).round();
     } else {
       layerAlpha = parentAlpha;
@@ -199,10 +197,10 @@ class ContentGroup implements DrawingContent, PathContent, KeyPathElement {
   }
 
   @override
-  Rect getBounds(Matrix4 parentMatrix, {bool applyParents}) {
+  Rect getBounds(Matrix4 parentMatrix, {required bool applyParents}) {
     _matrix.set(parentMatrix);
     if (_transformAnimation != null) {
-      _matrix.preConcat(_transformAnimation.getMatrix());
+      _matrix.preConcat(_transformAnimation!.getMatrix());
     }
     var bounds = Rect.zero;
     for (var i = _contents.length - 1; i >= 0; i--) {
@@ -223,8 +221,8 @@ class ContentGroup implements DrawingContent, PathContent, KeyPathElement {
       return;
     }
 
-    if ('__container' != name) {
-      currentPartialKeyPath = currentPartialKeyPath.addKey(name);
+    if ('__container' != name && name != null) {
+      currentPartialKeyPath = currentPartialKeyPath.addKey(name!);
 
       if (keyPath.fullyResolvesTo(name, depth)) {
         accumulator.add(currentPartialKeyPath.resolve(this));
@@ -245,9 +243,9 @@ class ContentGroup implements DrawingContent, PathContent, KeyPathElement {
   }
 
   @override
-  void addValueCallback<T>(T property, LottieValueCallback<T> /*?*/ callback) {
+  void addValueCallback<T>(T property, LottieValueCallback<T>? callback) {
     if (_transformAnimation != null) {
-      _transformAnimation.applyValueCallback(property, callback);
+      _transformAnimation!.applyValueCallback(property, callback);
     }
   }
 }

lib/src/animation/content/drawing_content.dart

@@ -1,10 +1,9 @@
 import 'dart:ui';
-import 'package:meta/meta.dart';
 import 'package:vector_math/vector_math_64.dart';
 import 'content.dart';
 
 abstract class DrawingContent extends Content {
   void draw(Canvas canvas, Size canvasSize, Matrix4 parentMatrix,
-      {@required int parentAlpha});
-  Rect getBounds(Matrix4 parentMatrix, {@required bool applyParents});
+      {required int parentAlpha});
+  Rect getBounds(Matrix4 parentMatrix, {required bool applyParents});
 }

lib/src/animation/content/ellipse_content.dart

@@ -22,10 +22,10 @@ class EllipseContent implements PathContent, KeyPathElementContent {
   final Path _path = PathFactory.create();
 
   @override
-  final String name;
+  final String? name;
   final LottieDrawable lottieDrawable;
-  final BaseKeyframeAnimation<dynamic, Offset> _sizeAnimation;
-  final BaseKeyframeAnimation<dynamic, Offset> _positionAnimation;
+  final BaseKeyframeAnimation<Object, Offset> _sizeAnimation;
+  final BaseKeyframeAnimation<Object, Offset> _positionAnimation;
   final CircleShape _circleShape;
 
   final CompoundTrimPathContent _trimPaths = CompoundTrimPathContent();
@@ -115,7 +115,7 @@ class EllipseContent implements PathContent, KeyPathElementContent {
   }
 
   @override
-  void addValueCallback<T>(T property, LottieValueCallback<T> /*?*/ callback) {
+  void addValueCallback<T>(T property, LottieValueCallback<T>? callback) {
     if (property == LottieProperty.ellipseSize) {
       _sizeAnimation.setValueCallback(callback as LottieValueCallback<Offset>);
     } else if (property == LottieProperty.position) {

lib/src/animation/content/fill_content.dart

@@ -22,12 +22,12 @@ class FillContent implements DrawingContent, KeyPathElementContent {
   final Paint _paint = Paint();
   final BaseLayer layer;
   @override
-  final String name;
+  final String? name;
   final bool _hidden;
   final List<PathContent> _paths = <PathContent>[];
-  BaseKeyframeAnimation<Color, Color> _colorAnimation;
-  BaseKeyframeAnimation<int, int> _opacityAnimation;
-  BaseKeyframeAnimation<ColorFilter, ColorFilter> /*?*/ _colorFilterAnimation;
+  late final BaseKeyframeAnimation<Color, Color> _colorAnimation;
+  late final BaseKeyframeAnimation<int, int> _opacityAnimation;
+  BaseKeyframeAnimation<ColorFilter, ColorFilter?>? _colorFilterAnimation;
   final LottieDrawable lottieDrawable;
 
   FillContent(this.lottieDrawable, this.layer, ShapeFill fill)
@@ -39,10 +39,10 @@ class FillContent implements DrawingContent, KeyPathElementContent {
 
     _path.fillType = fill.fillType;
 
-    _colorAnimation = fill.color.createAnimation();
+    _colorAnimation = fill.color!.createAnimation();
     _colorAnimation.addUpdateListener(onValueChanged);
     layer.addAnimation(_colorAnimation);
-    _opacityAnimation = fill.opacity.createAnimation();
+    _opacityAnimation = fill.opacity!.createAnimation();
     _opacityAnimation.addUpdateListener(onValueChanged);
     layer.addAnimation(_opacityAnimation);
   }
@@ -62,7 +62,8 @@ class FillContent implements DrawingContent, KeyPathElementContent {
   }
 
   @override
-  void draw(Canvas canvas, Size size, Matrix4 parentMatrix, {int parentAlpha}) {
+  void draw(Canvas canvas, Size size, Matrix4 parentMatrix,
+      {required int parentAlpha}) {
     if (_hidden) {
       return;
     }
@@ -76,7 +77,7 @@ class FillContent implements DrawingContent, KeyPathElementContent {
     }
 
     if (_colorFilterAnimation != null) {
-      _paint.colorFilter = _colorFilterAnimation.value;
+      _paint.colorFilter = _colorFilterAnimation!.value;
     }
 
     _path.reset();
@@ -93,7 +94,7 @@ class FillContent implements DrawingContent, KeyPathElementContent {
   }
 
   @override
-  Rect getBounds(Matrix4 parentMatrix, {bool applyParents}) {
+  Rect getBounds(Matrix4 parentMatrix, {required bool applyParents}) {
     _path.reset();
     for (var i = 0; i < _paths.length; i++) {
       _path.addPath(_paths[i].getPath(), Offset.zero,
@@ -101,8 +102,7 @@ class FillContent implements DrawingContent, KeyPathElementContent {
     }
     var outBounds = _path.getBounds();
     // Add padding to account for rounding errors.
-    outBounds = Rect.fromLTWH(outBounds.left - 1, outBounds.top - 1,
-        outBounds.right + 1, outBounds.bottom + 1);
+    outBounds = outBounds.inflate(1);
     return outBounds;
   }
 
@@ -114,7 +114,7 @@ class FillContent implements DrawingContent, KeyPathElementContent {
   }
 
   @override
-  void addValueCallback<T>(T property, LottieValueCallback<T> /*?*/ callback) {
+  void addValueCallback<T>(T property, LottieValueCallback<T>? callback) {
     if (property == LottieProperty.color) {
       _colorAnimation.setValueCallback(callback as LottieValueCallback<Color>);
     } else if (property == LottieProperty.opacity) {
@@ -128,8 +128,8 @@ class FillContent implements DrawingContent, KeyPathElementContent {
         _colorFilterAnimation = null;
       } else {
         _colorFilterAnimation = ValueCallbackKeyframeAnimation(
-            callback as LottieValueCallback<ColorFilter>);
-        _colorFilterAnimation.addUpdateListener(onValueChanged);
+            callback as LottieValueCallback<ColorFilter>, null)
+          ..addUpdateListener(onValueChanged);
         layer.addAnimation(_colorFilterAnimation);
       }
     }

lib/src/animation/content/gradient_fill_content.dart

@@ -33,9 +33,9 @@ class GradientFillContent implements DrawingContent, KeyPathElementContent {
   final BaseKeyframeAnimation<int, int> _opacityAnimation;
   final BaseKeyframeAnimation<Offset, Offset> _startPointAnimation;
   final BaseKeyframeAnimation<Offset, Offset> _endPointAnimation;
-  BaseKeyframeAnimation<ColorFilter, ColorFilter> /*?*/ _colorFilterAnimation;
-  ValueCallbackKeyframeAnimation<List<Color>,
-      List<Color>> /*?*/ _colorCallbackAnimation;
+  BaseKeyframeAnimation<ColorFilter, ColorFilter?>? _colorFilterAnimation;
+  ValueCallbackKeyframeAnimation<List<Color>, List<Color>>?
+      _colorCallbackAnimation;
   final LottieDrawable lottieDrawable;
   final int _cacheSteps;
 
@@ -62,7 +62,7 @@ class GradientFillContent implements DrawingContent, KeyPathElementContent {
   }
 
   @override
-  String get name => _fill.name;
+  String? get name => _fill.name;
 
   void invalidate() {
     lottieDrawable.invalidateSelf();
@@ -79,7 +79,8 @@ class GradientFillContent implements DrawingContent, KeyPathElementContent {
   }
 
   @override
-  void draw(Canvas canvas, Size size, Matrix4 parentMatrix, {int parentAlpha}) {
+  void draw(Canvas canvas, Size size, Matrix4 parentMatrix,
+      {required int parentAlpha}) {
     if (_fill.hidden) {
       return;
     }
@@ -99,7 +100,7 @@ class GradientFillContent implements DrawingContent, KeyPathElementContent {
     _paint.shader = gradient;
 
     if (_colorFilterAnimation != null) {
-      _paint.colorFilter = _colorFilterAnimation.value;
+      _paint.colorFilter = _colorFilterAnimation!.value;
     }
 
     var alpha =
@@ -117,7 +118,7 @@ class GradientFillContent implements DrawingContent, KeyPathElementContent {
   }
 
   @override
-  Rect getBounds(Matrix4 parentMatrix, {bool applyParents}) {
+  Rect getBounds(Matrix4 parentMatrix, {required bool applyParents}) {
     _path.reset();
     for (var i = 0; i < _paths.length; i++) {
       _path.addPath(_paths[i].getPath(), Offset.zero,
@@ -126,8 +127,7 @@ class GradientFillContent implements DrawingContent, KeyPathElementContent {
 
     var outBounds = _path.getBounds();
     // Add padding to account for rounding errors.
-    return Rect.fromLTWH(outBounds.left - 1, outBounds.top - 1,
-        outBounds.right + 1, outBounds.bottom + 1);
+    return outBounds.inflate(1);
   }
 
   Gradient _getLinearGradient() {
@@ -192,7 +192,7 @@ class GradientFillContent implements DrawingContent, KeyPathElementContent {
 
   List<Color> _applyDynamicColorsIfNeeded(List<Color> colors) {
     if (_colorCallbackAnimation != null) {
-      var dynamicColors = _colorCallbackAnimation.value;
+      var dynamicColors = _colorCallbackAnimation!.value;
       if (colors.length == dynamicColors.length) {
         for (var i = 0; i < colors.length; i++) {
           colors[i] = dynamicColors[i];
@@ -215,7 +215,7 @@ class GradientFillContent implements DrawingContent, KeyPathElementContent {
   }
 
   @override
-  void addValueCallback<T>(T property, LottieValueCallback<T> /*?*/ callback) {
+  void addValueCallback<T>(T property, LottieValueCallback<T>? callback) {
     if (property == LottieProperty.opacity) {
       _opacityAnimation.setValueCallback(callback as LottieValueCallback<int>);
     } else if (property == LottieProperty.colorFilter) {
@@ -227,8 +227,8 @@ class GradientFillContent implements DrawingContent, KeyPathElementContent {
         _colorFilterAnimation = null;
       } else {
         _colorFilterAnimation = ValueCallbackKeyframeAnimation(
-            callback as LottieValueCallback<ColorFilter>);
-        _colorFilterAnimation.addUpdateListener(invalidate);
+            callback as LottieValueCallback<ColorFilter>, null)
+          ..addUpdateListener(invalidate);
         layer.addAnimation(_colorFilterAnimation);
       }
     } else if (property == LottieProperty.gradientColor) {
@@ -240,8 +240,8 @@ class GradientFillContent implements DrawingContent, KeyPathElementContent {
         _colorCallbackAnimation = null;
       } else {
         _colorCallbackAnimation = ValueCallbackKeyframeAnimation(
-            callback as LottieValueCallback<List<Color>>);
-        _colorCallbackAnimation.addUpdateListener(invalidate);
+            callback as LottieValueCallback<List<Color>>, <Color>[])
+          ..addUpdateListener(invalidate);
         layer.addAnimation(_colorCallbackAnimation);
       }
     }

lib/src/animation/content/gradient_stroke_content.dart

@@ -18,7 +18,7 @@ class GradientStrokeContent extends BaseStrokeContent {
   static final int _cacheStepsMs = 32;
 
   @override
-  final String name;
+  final String? name;
   final bool _hidden;
   final _linearGradientCache = <int, Gradient>{};
   final _radialGradientCache = <int, Gradient>{};
@@ -28,8 +28,8 @@ class GradientStrokeContent extends BaseStrokeContent {
   final BaseKeyframeAnimation<GradientColor, GradientColor> _colorAnimation;
   final BaseKeyframeAnimation<Offset, Offset> _startPointAnimation;
   final BaseKeyframeAnimation<Offset, Offset> _endPointAnimation;
-  ValueCallbackKeyframeAnimation<List<Color>,
-      List<Color>> /*?*/ _colorCallbackAnimation;
+  ValueCallbackKeyframeAnimation<List<Color>, List<Color>>?
+      _colorCallbackAnimation;
 
   GradientStrokeContent(final LottieDrawable lottieDrawable, BaseLayer layer,
       GradientStroke stroke)
@@ -61,7 +61,8 @@ class GradientStrokeContent extends BaseStrokeContent {
   }
 
   @override
-  void draw(Canvas canvas, Size size, Matrix4 parentMatrix, {int parentAlpha}) {
+  void draw(Canvas canvas, Size size, Matrix4 parentMatrix,
+      {required int parentAlpha}) {
     if (_hidden) {
       return;
     }
@@ -142,7 +143,7 @@ class GradientStrokeContent extends BaseStrokeContent {
 
   List<Color> _applyDynamicColorsIfNeeded(List<Color> colors) {
     if (_colorCallbackAnimation != null) {
-      var dynamicColors = _colorCallbackAnimation.value;
+      var dynamicColors = _colorCallbackAnimation!.value;
       if (colors.length == dynamicColors.length) {
         for (var i = 0; i < colors.length; i++) {
           colors[i] = dynamicColors[i];
@@ -158,7 +159,7 @@ class GradientStrokeContent extends BaseStrokeContent {
   }
 
   @override
-  void addValueCallback<T>(T property, LottieValueCallback<T> /*?*/ callback) {
+  void addValueCallback<T>(T property, LottieValueCallback<T>? callback) {
     super.addValueCallback(property, callback);
     if (property == LottieProperty.gradientColor) {
       if (_colorCallbackAnimation != null) {
@@ -169,8 +170,8 @@ class GradientStrokeContent extends BaseStrokeContent {
         _colorCallbackAnimation = null;
       } else {
         _colorCallbackAnimation = ValueCallbackKeyframeAnimation(
-            callback as LottieValueCallback<List<Color>>);
-        _colorCallbackAnimation.addUpdateListener(onUpdateListener);
+            callback as LottieValueCallback<List<Color>>, <Color>[])
+          ..addUpdateListener(onUpdateListener);
         layer.addAnimation(_colorCallbackAnimation);
       }
     }

lib/src/animation/content/polystar_content.dart

@@ -28,13 +28,13 @@ class PolystarContent implements PathContent, KeyPathElementContent {
 
   final LottieDrawable lottieDrawable;
   final PolystarShape _polystarShape;
-  final BaseKeyframeAnimation<dynamic, double> _pointsAnimation;
-  final BaseKeyframeAnimation<dynamic, Offset> _positionAnimation;
-  final BaseKeyframeAnimation<dynamic, double> _rotationAnimation;
-  final BaseKeyframeAnimation<dynamic, double> /*?*/ _innerRadiusAnimation;
-  final BaseKeyframeAnimation<dynamic, double> _outerRadiusAnimation;
-  final BaseKeyframeAnimation<dynamic, double> /*?*/ _innerRoundednessAnimation;
-  final BaseKeyframeAnimation<dynamic, double> _outerRoundednessAnimation;
+  final BaseKeyframeAnimation<Object, double> _pointsAnimation;
+  final BaseKeyframeAnimation<Object, Offset> _positionAnimation;
+  final BaseKeyframeAnimation<Object, double> _rotationAnimation;
+  final BaseKeyframeAnimation<Object, double>? _innerRadiusAnimation;
+  final BaseKeyframeAnimation<Object, double> _outerRadiusAnimation;
+  final BaseKeyframeAnimation<Object, double>? _innerRoundednessAnimation;
+  final BaseKeyframeAnimation<Object, double> _outerRoundednessAnimation;
 
   final _trimPaths = CompoundTrimPathContent();
   bool _isPathValid = false;
@@ -47,11 +47,11 @@ class PolystarContent implements PathContent, KeyPathElementContent {
         _outerRoundednessAnimation =
             _polystarShape.outerRoundedness.createAnimation(),
         _innerRadiusAnimation = _polystarShape.type == PolystarShapeType.star
-            ? _polystarShape.innerRadius.createAnimation()
+            ? _polystarShape.innerRadius!.createAnimation()
             : null,
         _innerRoundednessAnimation =
             _polystarShape.type == PolystarShapeType.star
-                ? _polystarShape.innerRoundedness.createAnimation()
+                ? _polystarShape.innerRoundedness!.createAnimation()
                 : null {
     layer.addAnimation(_pointsAnimation);
     layer.addAnimation(_positionAnimation);
@@ -69,8 +69,8 @@ class PolystarContent implements PathContent, KeyPathElementContent {
     _outerRadiusAnimation.addUpdateListener(invalidate);
     _outerRoundednessAnimation.addUpdateListener(invalidate);
     if (_polystarShape.type == PolystarShapeType.star) {
-      _innerRadiusAnimation.addUpdateListener(invalidate);
-      _innerRoundednessAnimation.addUpdateListener(invalidate);
+      _innerRadiusAnimation!.addUpdateListener(invalidate);
+      _innerRoundednessAnimation!.addUpdateListener(invalidate);
     }
   }
 
@@ -123,12 +123,11 @@ class PolystarContent implements PathContent, KeyPathElementContent {
   }
 
   @override
-  String get name => _polystarShape.name;
+  String? get name => _polystarShape.name;
 
   void _createStarPath() {
     var points = _pointsAnimation.value;
-    var currentAngle =
-        _rotationAnimation == null ? 0.0 : _rotationAnimation.value;
+    var currentAngle = _rotationAnimation.value;
     // Start at +y instead of +x
     currentAngle -= 90;
     // convert to radians
@@ -143,16 +142,13 @@ class PolystarContent implements PathContent, KeyPathElementContent {
 
     var outerRadius = _outerRadiusAnimation.value;
     //noinspection ConstantConditions
-    var innerRadius = _innerRadiusAnimation.value;
+    var innerRadius = _innerRadiusAnimation!.value;
 
     var innerRoundedness = 0.0;
     if (_innerRoundednessAnimation != null) {
-      innerRoundedness = _innerRoundednessAnimation.value / 100.0;
-    }
-    var outerRoundedness = 0.0;
-    if (_outerRoundednessAnimation != null) {
-      outerRoundedness = _outerRoundednessAnimation.value / 100.0;
+      innerRoundedness = _innerRoundednessAnimation!.value / 100.0;
     }
+    var outerRoundedness = _outerRoundednessAnimation.value / 100.0;
 
     double x;
     double y;
@@ -235,8 +231,7 @@ class PolystarContent implements PathContent, KeyPathElementContent {
 
   void _createPolygonPath() {
     var points = _pointsAnimation.value.floor();
-    var currentAngle =
-        _rotationAnimation == null ? 0.0 : _rotationAnimation.value;
+    var currentAngle = _rotationAnimation.value;
     // Start at +y instead of +x
     currentAngle -= 90;
     // convert to radians
@@ -297,7 +292,7 @@ class PolystarContent implements PathContent, KeyPathElementContent {
   }
 
   @override
-  void addValueCallback<T>(T property, LottieValueCallback<T> /*?*/ callback) {
+  void addValueCallback<T>(T property, LottieValueCallback<T>? callback) {
     if (property == LottieProperty.polystarPoints) {
       _pointsAnimation
           .setValueCallback(callback as LottieValueCallback<double>);
@@ -309,14 +304,14 @@ class PolystarContent implements PathContent, KeyPathElementContent {
           .setValueCallback(callback as LottieValueCallback<Offset>);
     } else if (property == LottieProperty.polystarInnerRadius &&
         _innerRadiusAnimation != null) {
-      _innerRadiusAnimation
+      _innerRadiusAnimation!
           .setValueCallback(callback as LottieValueCallback<double>);
     } else if (property == LottieProperty.polystarOuterRadius) {
       _outerRadiusAnimation
           .setValueCallback(callback as LottieValueCallback<double>);
     } else if (property == LottieProperty.polystarInnerRoundedness &&
         _innerRoundednessAnimation != null) {
-      _innerRoundednessAnimation
+      _innerRoundednessAnimation!
           .setValueCallback(callback as LottieValueCallback<double>);
     } else if (property == LottieProperty.polystarOuterRoundedness) {
       _outerRoundednessAnimation

lib/src/animation/content/rectangle_content.dart

@@ -21,12 +21,12 @@ class RectangleContent implements KeyPathElementContent, PathContent {
   final _path = PathFactory.create();
 
   @override
-  final String name;
+  final String? name;
   final bool _hidden;
   final LottieDrawable lottieDrawable;
-  final BaseKeyframeAnimation<dynamic, Offset> _positionAnimation;
-  final BaseKeyframeAnimation<dynamic, Offset> _sizeAnimation;
-  final BaseKeyframeAnimation<dynamic, double> _cornerRadiusAnimation;
+  final BaseKeyframeAnimation<Object, Offset> _positionAnimation;
+  final BaseKeyframeAnimation<Object, Offset> _sizeAnimation;
+  final BaseKeyframeAnimation<Object, double> _cornerRadiusAnimation;
 
   final CompoundTrimPathContent _trimPaths = CompoundTrimPathContent();
   bool _isPathValid = false;
@@ -81,8 +81,7 @@ class RectangleContent implements KeyPathElementContent, PathContent {
     var size = _sizeAnimation.value;
     var halfWidth = size.dx / 2.0;
     var halfHeight = size.dy / 2.0;
-    var radius =
-        _cornerRadiusAnimation == null ? 0.0 : _cornerRadiusAnimation.value;
+    var radius = _cornerRadiusAnimation.value;
     var maxRadius = min(halfWidth, halfHeight);
     if (radius > maxRadius) {
       radius = maxRadius;
@@ -164,7 +163,7 @@ class RectangleContent implements KeyPathElementContent, PathContent {
   }
 
   @override
-  void addValueCallback<T>(T property, LottieValueCallback<T> /*?*/ callback) {
+  void addValueCallback<T>(T property, LottieValueCallback<T>? callback) {
     if (property == LottieProperty.rectangleSize) {
       _sizeAnimation.setValueCallback(callback as LottieValueCallback<Offset>);
     } else if (property == LottieProperty.position) {

lib/src/animation/content/repeater_content.dart

@@ -33,7 +33,7 @@ class RepeaterContent
   final BaseKeyframeAnimation<double, double> _copies;
   final BaseKeyframeAnimation<double, double> _offset;
   final TransformKeyframeAnimation _transform;
-  ContentGroup _contentGroup;
+  ContentGroup? _contentGroup;
 
   RepeaterContent(this.lottieDrawable, this.layer, this._repeater)
       : _copies = _repeater.copies.createAnimation(),
@@ -83,16 +83,16 @@ class RepeaterContent
   }
 
   @override
-  String get name => _repeater.name;
+  String? get name => _repeater.name;
 
   @override
   void setContents(List<Content> contentsBefore, List<Content> contentsAfter) {
-    _contentGroup.setContents(contentsBefore, contentsAfter);
+    _contentGroup!.setContents(contentsBefore, contentsAfter);
   }
 
   @override
   Path getPath() {
-    var contentPath = _contentGroup.getPath();
+    var contentPath = _contentGroup!.getPath();
     _path.reset();
     var copies = _copies.value;
     var offset = _offset.value;
@@ -104,23 +104,24 @@ class RepeaterContent
   }
 
   @override
-  void draw(Canvas canvas, Size size, Matrix4 parentMatrix, {int parentAlpha}) {
+  void draw(Canvas canvas, Size size, Matrix4 parentMatrix,
+      {required int parentAlpha}) {
     var copies = _copies.value;
     var offset = _offset.value;
-    var startOpacity = _transform.startOpacity.value / 100.0;
-    var endOpacity = _transform.endOpacity.value / 100.0;
+    var startOpacity = _transform.startOpacity!.value / 100.0;
+    var endOpacity = _transform.endOpacity!.value / 100.0;
     for (var i = copies.toInt() - 1; i >= 0; i--) {
       _matrix.set(parentMatrix);
       _matrix.preConcat(_transform.getMatrixForRepeater(i + offset));
       var newAlpha =
-          parentAlpha * lerpDouble(startOpacity, endOpacity, i / copies);
-      _contentGroup.draw(canvas, size, _matrix, parentAlpha: newAlpha.round());
+          parentAlpha * lerpDouble(startOpacity, endOpacity, i / copies)!;
+      _contentGroup!.draw(canvas, size, _matrix, parentAlpha: newAlpha.round());
     }
   }
 
   @override
-  Rect getBounds(Matrix4 parentMatrix, {bool applyParents}) {
-    return _contentGroup.getBounds(parentMatrix, applyParents: applyParents);
+  Rect getBounds(Matrix4 parentMatrix, {required bool applyParents}) {
+    return _contentGroup!.getBounds(parentMatrix, applyParents: applyParents);
   }
 
   void _invalidate() {
@@ -135,7 +136,7 @@ class RepeaterContent
   }
 
   @override
-  void addValueCallback<T>(T property, LottieValueCallback<T> /*?*/ callback) {
+  void addValueCallback<T>(T property, LottieValueCallback<T>? callback) {
     if (_transform.applyValueCallback(property, callback)) {
       return;
     }

lib/src/animation/content/shape_content.dart

@@ -17,7 +17,7 @@ class ShapeContent implements PathContent {
   final ShapePath _shape;
 
   final LottieDrawable lottieDrawable;
-  final BaseKeyframeAnimation<dynamic, Path> _shapeAnimation;
+  final BaseKeyframeAnimation<Object, Path> _shapeAnimation;
 
   bool _isPathValid = false;
   final _trimPaths = CompoundTrimPathContent();
@@ -48,7 +48,7 @@ class ShapeContent implements PathContent {
   }
 
   @override
-  String get name => _shape.name;
+  String? get name => _shape.name;
 
   @override
   Path getPath() {

lib/src/animation/content/stroke_content.dart

@@ -11,10 +11,10 @@ import 'base_stroke_content.dart';
 
 class StrokeContent extends BaseStrokeContent {
   @override
-  final String name;
+  final String? name;
   final bool _hidden;
   final BaseKeyframeAnimation<Color, Color> _colorAnimation;
-  BaseKeyframeAnimation<ColorFilter, ColorFilter> /*?*/ _colorFilterAnimation;
+  BaseKeyframeAnimation<ColorFilter, ColorFilter?>? _colorFilterAnimation;
 
   StrokeContent(
       final LottieDrawable lottieDrawable, BaseLayer layer, ShapeStroke stroke)
@@ -34,19 +34,20 @@ class StrokeContent extends BaseStrokeContent {
   }
 
   @override
-  void draw(Canvas canvas, Size size, Matrix4 parentMatrix, {int parentAlpha}) {
+  void draw(Canvas canvas, Size size, Matrix4 parentMatrix,
+      {required int parentAlpha}) {
     if (_hidden) {
       return;
     }
     paint.color = _colorAnimation.value.withAlpha(paint.color.alpha);
     if (_colorFilterAnimation != null) {
-      paint.colorFilter = _colorFilterAnimation.value;
+      paint.colorFilter = _colorFilterAnimation!.value;
     }
     super.draw(canvas, size, parentMatrix, parentAlpha: parentAlpha);
   }
 
   @override
-  void addValueCallback<T>(T property, LottieValueCallback<T> /*?*/ callback) {
+  void addValueCallback<T>(T property, LottieValueCallback<T>? callback) {
     super.addValueCallback(property, callback);
     if (property == LottieProperty.strokeColor) {
       _colorAnimation.setValueCallback(callback as LottieValueCallback<Color>);
@@ -58,10 +59,9 @@ class StrokeContent extends BaseStrokeContent {
       if (callback == null) {
         _colorFilterAnimation = null;
       } else {
-        _colorFilterAnimation =
-            ValueCallbackKeyframeAnimation<ColorFilter, ColorFilter>(
-                callback as LottieValueCallback<ColorFilter>);
-        _colorFilterAnimation.addUpdateListener(onUpdateListener);
+        _colorFilterAnimation = ValueCallbackKeyframeAnimation(
+            callback as LottieValueCallback<ColorFilter>, null)
+          ..addUpdateListener(onUpdateListener);
         layer.addAnimation(_colorAnimation);
       }
     }

lib/src/animation/content/trim_path_content.dart

@@ -5,13 +5,13 @@ import 'content.dart';
 
 class TrimPathContent implements Content {
   @override
-  final String name;
+  final String? name;
   final bool hidden;
   final _listeners = <void Function()>[];
-  final ShapeTrimPathType type;
-  final BaseKeyframeAnimation<dynamic, double> start;
-  final BaseKeyframeAnimation<dynamic, double> end;
-  final BaseKeyframeAnimation<dynamic, double> offset;
+  final ShapeTrimPathType? type;
+  final BaseKeyframeAnimation<Object, double> start;
+  final BaseKeyframeAnimation<Object, double> end;
+  final BaseKeyframeAnimation<Object, double> offset;
 
   TrimPathContent(BaseLayer layer, ShapeTrimPath trimPath)
       : name = trimPath.name,

lib/src/animation/keyframe/base_keyframe_animation.dart

@@ -5,16 +5,16 @@ import '../../value/lottie_value_callback.dart';
 
 /// @param <K> Keyframe type
 /// @param <A> Animation type
-abstract class BaseKeyframeAnimation<K, A> {
+abstract class BaseKeyframeAnimation<K extends Object, A extends Object?> {
 // This is not a Set because we don't want to create an iterator object on every setProgress.
   final listeners = <void Function()>[];
   bool _isDiscrete = false;
 
   final _KeyframesWrapper<K> _keyframesWrapper;
   double _progress = 0;
-  LottieValueCallback<A> /*?*/ valueCallback;
+  LottieValueCallback<A>? valueCallback;
 
-  A /*?*/ _cachedGetValue;
+  A? _cachedGetValue;
 
   double _cachedStartDelayProgress = -1.0;
   double _cachedEndProgress = -1.0;
@@ -85,7 +85,7 @@ abstract class BaseKeyframeAnimation<K, A> {
     if (keyframe.isStatic) {
       return 0.0;
     }
-    return keyframe.interpolator.transform(getLinearCurrentKeyframeProgress());
+    return keyframe.interpolator!.transform(getLinearCurrentKeyframeProgress());
   }
 
   double getStartDelayProgress() {
@@ -106,7 +106,7 @@ abstract class BaseKeyframeAnimation<K, A> {
     var progress = getInterpolatedCurrentKeyframeProgress();
     if (valueCallback == null &&
         _keyframesWrapper.isCachedValueEnabled(progress)) {
-      return _cachedGetValue;
+      return _cachedGetValue!;
     }
 
     final keyframe = getCurrentKeyframe();
@@ -125,9 +125,9 @@ abstract class BaseKeyframeAnimation<K, A> {
     _progress = value;
   }
 
-  void setValueCallback(LottieValueCallback<A> /*?*/ valueCallback) {
+  void setValueCallback(LottieValueCallback<A>? valueCallback) {
     if (this.valueCallback != null) {
-      this.valueCallback.setAnimation(null);
+      this.valueCallback!.setAnimation(null);
     }
     this.valueCallback = valueCallback;
     if (valueCallback != null) {
@@ -240,8 +240,8 @@ class _SingleKeyframeWrapper<T> implements _KeyframesWrapper<T> {
 
 class _KeyframesWrapperImpl<T> implements _KeyframesWrapper<T> {
   final List<Keyframe<T>> keyframes;
-  Keyframe<T> _currentKeyframe;
-  Keyframe<T> _cachedCurrentKeyframe;
+  Keyframe<T>? _currentKeyframe;
+  Keyframe<T>? _cachedCurrentKeyframe;
   double _cachedInterpolatedProgress = -1;
 
   _KeyframesWrapperImpl(this.keyframes) {
@@ -255,8 +255,8 @@ class _KeyframesWrapperImpl<T> implements _KeyframesWrapper<T> {
 
   @override
   bool isValueChanged(double progress) {
-    if (_currentKeyframe.containsProgress(progress)) {
-      return !_currentKeyframe.isStatic;
+    if (_currentKeyframe!.containsProgress(progress)) {
+      return !_currentKeyframe!.isStatic;
     }
     _currentKeyframe = findKeyframe(progress);
     return true;
@@ -281,7 +281,7 @@ class _KeyframesWrapperImpl<T> implements _KeyframesWrapper<T> {
 
   @override
   Keyframe<T> getCurrentKeyframe() {
-    return _currentKeyframe;
+    return _currentKeyframe!;
   }
 
   @override