Migrated to NNBD (null-safety) 🎉 (#195)

* Updated dependencies
* Minimum Dart SDK is 2.12.0-0
* Resolves #184

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 4.0.0
+
+- Migrated to nnbd(null-safety)
+
 ## 3.1.2
 - Fixed insecure links in readme.
 
@@ -11,7 +15,7 @@
 
 ## 3.0.2
 
-- Fixed major bug [#168](https://github.com/aagarwal1012/Animated-Text-Kit/issues/168), introduced with version 3 
+- Fixed major bug [#168](https://github.com/aagarwal1012/Animated-Text-Kit/issues/168), introduced with version 3
 - Updated the `example` app to show a _Tap Count_
 - Optimized the `dispose` for `AnimatedTextKit`
 - Added missing return type to `onNext` function signatures
@@ -147,7 +151,7 @@
   - `displayFullTextOnTap` - If true, tapping the screen will stop current animated text, and display it fully.
   - `stopPauseOnTap` - If true, tapping during a pause will stop it and start the next text animation.
 
-- **Better control over Animated Texts:**  
+- **Better control over Animated Texts:**
   Callbacks added:
   - `onNext(int index, bool isLast)` - This callback will be called before the next text animation, after the previous ones pause.
   - `onNextBeforePause(int index, bool isLast)` - This callback will be called before the next text animation, before the previous one's pause.

example/lib/main.dart

@@ -22,16 +22,14 @@ class _MyAppState extends State<MyApp> {
 }
 
 class MyHomePage extends StatefulWidget {
-  MyHomePage({
-    Key key,
-  }) : super(key: key);
+  MyHomePage({Key? key}) : super(key: key);
 
   @override
   _MyHomePageState createState() => _MyHomePageState();
 }
 
 class _MyHomePageState extends State<MyHomePage> {
-  List<AnimatedTextExample> _examples;
+  late List<AnimatedTextExample> _examples;
   int _index = 0;
   int _tapCount = 0;
 
@@ -95,16 +93,16 @@ class _MyHomePageState extends State<MyHomePage> {
 
 class AnimatedTextExample {
   final String label;
-  final Color color;
+  final Color? color;
   final Widget child;
   const AnimatedTextExample({
-    @required this.label,
-    @required this.color,
-    @required this.child,
+    required this.label,
+    required this.color,
+    required this.child,
   });
 }
 
-List<AnimatedTextExample> animatedTextExamples({VoidCallback onTap}) =>
+List<AnimatedTextExample> animatedTextExamples({VoidCallback? onTap}) =>
     <AnimatedTextExample>[
       AnimatedTextExample(
         label: 'Rotate',

example/pubspec.yaml

@@ -2,7 +2,7 @@ name: example
 description: An example app to show the use of Animation Text Kit.
 
 environment:
-  sdk: ">=2.10.0 <3.0.0"
+  sdk: ">=2.12.0-0 <3.0.0"
   flutter: ">=1.22.0"
 
 dependencies:

lib/src/animated_text.dart

@@ -29,18 +29,14 @@ abstract class AnimatedText {
   final Characters textCharacters;
 
   AnimatedText({
-    @required this.text,
+    required this.text,
     this.textAlign = TextAlign.start,
-    @required this.textStyle,
-    @required this.duration,
-  })  : assert(null != text),
-        assert(null != textAlign),
-        assert(null != textStyle),
-        assert(null != duration),
-        textCharacters = text.characters;
+    required this.textStyle,
+    required this.duration,
+  }) : textCharacters = text.characters;
 
   /// Return the remaining Duration for the Animation (when applicable).
-  Duration get remaining => null;
+  Duration? get remaining => null;
 
   /// Initialize the Animation.
   void initAnimation(AnimationController controller);
@@ -58,7 +54,7 @@ abstract class AnimatedText {
   Widget completeText() => textWidget(text);
 
   /// Widget showing animated text, based on animation value(s).
-  Widget animatedBuilder(BuildContext context, Widget child);
+  Widget animatedBuilder(BuildContext context, Widget? child);
 }
 
 /// Base class for Animated Text widgets.
@@ -82,22 +78,22 @@ class AnimatedTextKit extends StatefulWidget {
   final bool stopPauseOnTap;
 
   /// Adds the onTap [VoidCallback] to the animated widget.
-  final VoidCallback onTap;
+  final VoidCallback? onTap;
 
   /// Adds the onFinished [VoidCallback] to the animated widget.
   ///
   /// This method will run only if [isRepeatingAnimation] is set to false.
-  final VoidCallback onFinished;
+  final VoidCallback? onFinished;
 
   /// Adds the onNext callback to the animated widget.
   ///
   /// Will be called right before the next text, after the pause parameter
-  final void Function(int, bool) onNext;
+  final void Function(int, bool)? onNext;
 
   /// Adds the onNextBeforePause callback to the animated widget.
   ///
   /// Will be called at the end of n-1 animation, before the pause parameter
-  final void Function(int, bool) onNextBeforePause;
+  final void Function(int, bool)? onNextBeforePause;
 
   /// Set if the animation should not repeat by changing the value of it to false.
   ///
@@ -116,8 +112,8 @@ class AnimatedTextKit extends StatefulWidget {
   final int totalRepeatCount;
 
   const AnimatedTextKit({
-    Key key,
-    @required this.animatedTexts,
+    Key? key,
+    required this.animatedTexts,
     this.pause = const Duration(milliseconds: 1000),
     this.displayFullTextOnTap = false,
     this.stopPauseOnTap = false,
@@ -128,14 +124,8 @@ class AnimatedTextKit extends StatefulWidget {
     this.isRepeatingAnimation = true,
     this.totalRepeatCount = 3,
     this.repeatForever = false,
-  })  : assert(null != animatedTexts && animatedTexts.length > 0),
-        assert(null != pause),
-        assert(null != displayFullTextOnTap),
-        assert(null != stopPauseOnTap),
-        assert(null != isRepeatingAnimation),
-        assert(null != repeatForever),
-        assert(
-            !isRepeatingAnimation || null != totalRepeatCount || repeatForever),
+  })  : assert(animatedTexts.length > 0),
+        assert(!isRepeatingAnimation || totalRepeatCount > 0 || repeatForever),
         assert(null == onFinished || !repeatForever),
         super(key: key);
 
@@ -146,17 +136,17 @@ class AnimatedTextKit extends StatefulWidget {
 
 class _AnimatedTextKitState extends State<AnimatedTextKit>
     with TickerProviderStateMixin {
-  AnimationController _controller;
+  late AnimationController _controller;
 
-  AnimatedText _currentAnimatedText;
+  late AnimatedText _currentAnimatedText;
 
   int _currentRepeatCount = 0;
 
   int _index = 0;
 
   bool _isCurrentlyPausing = false;
 
-  Timer _timer;
+  Timer? _timer;
 
   @override
   void initState() {
@@ -249,7 +239,7 @@ class _AnimatedTextKitState extends State<AnimatedTextKit>
   void _animationEndCallback(AnimationStatus state) {
     if (state == AnimationStatus.completed) {
       _setPause();
-      assert(null == _timer || !_timer.isActive);
+      assert(null == _timer || !_timer!.isActive);
       _timer = Timer(widget.pause, _nextAnimation);
     }
   }
@@ -270,7 +260,7 @@ class _AnimatedTextKitState extends State<AnimatedTextKit>
 
         _setPause();
 
-        assert(null == _timer || !_timer.isActive);
+        assert(null == _timer || !_timer!.isActive);
         _timer = Timer(
           Duration(
             milliseconds: max(

lib/src/colorize.dart

@@ -24,27 +24,26 @@ class ColorizeAnimatedText extends AnimatedText {
   ColorizeAnimatedText(
     String text, {
     TextAlign textAlign = TextAlign.start,
-    @required TextStyle textStyle,
+    required TextStyle textStyle,
     this.speed = const Duration(milliseconds: 200),
-    @required this.colors,
+    required this.colors,
     this.textDirection = TextDirection.ltr,
-  })  : assert(null != speed),
-        assert(null != colors && colors.length > 1),
+  })  : assert(colors.length > 1),
         super(
           text: text,
           textAlign: textAlign,
           textStyle: textStyle,
           duration: speed * text.characters.length,
         );
 
-  Animation<double> _colorShifter, _fadeIn, _fadeOut;
+  late Animation<double> _colorShifter, _fadeIn, _fadeOut;
   // Copy of colors that may be reversed when RTL.
-  List<Color> _colors;
+  late List<Color> _colors;
 
   @override
   void initAnimation(AnimationController controller) {
     final tuning = (300.0 * colors.length) *
-        (textStyle.fontSize / 24.0) *
+        (textStyle.fontSize! / 24.0) *
         0.75 *
         (textCharacters.length / 15.0);
 
@@ -93,15 +92,15 @@ class ColorizeAnimatedText extends AnimatedText {
     );
     return Text(
       text,
-      style: textStyle?.merge(
+      style: textStyle.merge(
         TextStyle(foreground: Paint()..shader = linearGradient),
       ),
       textAlign: textAlign,
     );
   }
 
   @override
-  Widget animatedBuilder(BuildContext context, Widget child) {
+  Widget animatedBuilder(BuildContext context, Widget? child) {
     return Opacity(
       opacity: _fadeIn.value != 1.0 ? _fadeIn.value : _fadeOut.value,
       child: completeText(),
@@ -114,18 +113,18 @@ class ColorizeAnimatedText extends AnimatedText {
 /// ![Colorize example](https://raw.githubusercontent.com/aagarwal1012/Animated-Text-Kit/master/display/colorize.gif)
 class ColorizeAnimatedTextKit extends AnimatedTextKit {
   ColorizeAnimatedTextKit({
-    Key key,
-    @required List<String> text,
+    Key? key,
+    required List<String> text,
     TextAlign textAlign = TextAlign.start,
     TextDirection textDirection = TextDirection.ltr,
-    TextStyle textStyle,
-    List<Color> colors,
+    required TextStyle textStyle,
+    required List<Color> colors,
     Duration speed = const Duration(milliseconds: 200),
     Duration pause = const Duration(milliseconds: 1000),
-    VoidCallback onTap,
-    void Function(int, bool) onNext,
-    void Function(int, bool) onNextBeforePause,
-    VoidCallback onFinished,
+    VoidCallback? onTap,
+    void Function(int, bool)? onNext,
+    void Function(int, bool)? onNextBeforePause,
+    VoidCallback? onFinished,
     bool isRepeatingAnimation = true,
     int totalRepeatCount = 3,
     bool repeatForever = false,
@@ -134,7 +133,13 @@ class ColorizeAnimatedTextKit extends AnimatedTextKit {
   }) : super(
           key: key,
           animatedTexts: _animatedTexts(
-              text, textAlign, textStyle, speed, colors, textDirection),
+            text,
+            textAlign,
+            textStyle,
+            speed,
+            colors,
+            textDirection,
+          ),
           pause: pause,
           displayFullTextOnTap: displayFullTextOnTap,
           stopPauseOnTap: stopPauseOnTap,

lib/src/fade.dart

@@ -8,7 +8,7 @@ class FadeAnimatedText extends AnimatedText {
   FadeAnimatedText(
     String text, {
     TextAlign textAlign = TextAlign.start,
-    @required TextStyle textStyle,
+    required TextStyle textStyle,
     Duration duration = const Duration(milliseconds: 2000),
   }) : super(
           text: text,
@@ -17,7 +17,7 @@ class FadeAnimatedText extends AnimatedText {
           duration: duration,
         );
 
-  Animation<double> _fadeIn, _fadeOut;
+  late Animation<double> _fadeIn, _fadeOut;
 
   @override
   void initAnimation(AnimationController controller) {
@@ -40,7 +40,7 @@ class FadeAnimatedText extends AnimatedText {
   Widget completeText() => SizedBox.shrink();
 
   @override
-  Widget animatedBuilder(BuildContext context, Widget child) {
+  Widget animatedBuilder(BuildContext context, Widget? child) {
     return Opacity(
       opacity: _fadeIn.value != 1.0 ? _fadeIn.value : _fadeOut.value,
       child: textWidget(text),
@@ -53,16 +53,16 @@ class FadeAnimatedText extends AnimatedText {
 /// ![Fade example](https://raw.githubusercontent.com/aagarwal1012/Animated-Text-Kit/master/display/fade.gif)
 class FadeAnimatedTextKit extends AnimatedTextKit {
   FadeAnimatedTextKit({
-    Key key,
-    @required List<String> text,
+    Key? key,
+    required List<String> text,
     TextAlign textAlign = TextAlign.start,
-    TextStyle textStyle,
+    required TextStyle textStyle,
     Duration duration = const Duration(milliseconds: 2000),
     Duration pause = const Duration(milliseconds: 500),
-    VoidCallback onTap,
-    void Function(int, bool) onNext,
-    void Function(int, bool) onNextBeforePause,
-    VoidCallback onFinished,
+    VoidCallback? onTap,
+    void Function(int, bool)? onNext,
+    void Function(int, bool)? onNextBeforePause,
+    VoidCallback? onFinished,
     bool isRepeatingAnimation = true,
     int totalRepeatCount = 3,
     bool repeatForever = false,