Migrate to null safety

example/lib/main.dart

@@ -3,7 +3,7 @@ import 'screens/audio_screen.dart';
 import 'widgets/player.dart';
 import 'utils.dart';
 
-ValueNotifier<AudioObject> currentlyPlaying = ValueNotifier(null);
+ValueNotifier<AudioObject?> currentlyPlaying = ValueNotifier(null);
 
 const double playerMinHeight = 70;
 const double playerMaxHeight = 370;
@@ -48,30 +48,20 @@ class _MyHomePageState extends State<MyHomePage> {
           ),
           ValueListenableBuilder(
             valueListenable: currentlyPlaying,
-            builder:
+            builder: (BuildContext context, AudioObject? audioObject,
-                (BuildContext context, AudioObject audioObject, Widget child) =>
+                    Widget? child) =>
-                    audioObject != null
+                audioObject != null
-                        ? DetailedPlayer(audioObject: audioObject)
+                    ? DetailedPlayer(audioObject: audioObject)
-                        : Container(),
+                    : Container(),
           ),
         ],
       ),
       bottomNavigationBar: ValueListenableBuilder(
         valueListenable: playerExpandProgress,
-        child: BottomNavigationBar(
+        builder: (BuildContext context, double height, Widget? child) {
-          currentIndex: 0,
-          selectedItemColor: Colors.blue,
-          items: <BottomNavigationBarItem>[
-            BottomNavigationBarItem(icon: Icon(Icons.home), label: 'Feed'),
-            BottomNavigationBarItem(
-                icon: Icon(Icons.library_books), label: 'Library'),
-          ],
-        ),
-        builder: (BuildContext context, double height, Widget child) {
           final value = percentageFromValueInRange(
               min: playerMinHeight, max: playerMaxHeight, value: height);
 
-          if (value == null) return child;
           var opacity = 1 - value;
           if (opacity < 0) opacity = 0;
           if (opacity > 1) opacity = 1;
@@ -85,6 +75,15 @@ class _MyHomePageState extends State<MyHomePage> {
             ),
           );
         },
+        child: BottomNavigationBar(
+          currentIndex: 0,
+          selectedItemColor: Colors.blue,
+          items: <BottomNavigationBarItem>[
+            BottomNavigationBarItem(icon: Icon(Icons.home), label: 'Feed'),
+            BottomNavigationBarItem(
+                icon: Icon(Icons.library_books), label: 'Library'),
+          ],
+        ),
       ),
     );
   }

example/lib/screens/audio_screen.dart

@@ -27,7 +27,7 @@ const Set<AudioObject> audioExamples = {
 class AudioUi extends StatelessWidget {
   final OnTap onTap;
 
-  const AudioUi({Key key, @required this.onTap}) : super(key: key);
+  const AudioUi({Key? key, required this.onTap}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {

example/lib/utils.dart

@@ -1,5 +1,3 @@
-import 'package:flutter/foundation.dart';
-
 class AudioObject {
   final String title, subtitle, img;
 
@@ -7,10 +5,10 @@ class AudioObject {
 }
 
 double valueFromPercentageInRange(
-    {@required final double min, max, percentage}) {
+    {required final double min, max, percentage}) {
   return percentage * (max - min) + min;
 }
 
-double percentageFromValueInRange({@required final double min, max, value}) {
+double percentageFromValueInRange({required final double min, max, value}) {
   return (value - min) / (max - min);
 }

example/lib/widgets/audio_list_tile.dart

@@ -9,7 +9,7 @@ class AudioListTile extends StatelessWidget {
   final Function onTap;
 
   const AudioListTile(
-      {Key key, @required this.audioObject, @required this.onTap})
+      {Key? key, required this.audioObject, required this.onTap})
       : super(key: key);
 
   @override
@@ -32,7 +32,7 @@ class AudioListTile extends StatelessWidget {
       ),
       trailing: IconButton(
         icon: Icon(Icons.play_arrow_outlined),
-        onPressed: onTap,
+        onPressed: () => onTap(),
       ),
     );
   }

example/lib/widgets/player.dart

@@ -12,7 +12,7 @@ final MiniplayerController controller = MiniplayerController();
 class DetailedPlayer extends StatelessWidget {
   final AudioObject audioObject;
 
-  const DetailedPlayer({Key key, @required this.audioObject}) : super(key: key);
+  const DetailedPlayer({Key? key, required this.audioObject}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -150,13 +150,13 @@ class DetailedPlayer extends StatelessWidget {
                             Text(audioObject.title,
                                 style: Theme.of(context)
                                     .textTheme
-                                    .bodyText2
+                                    .bodyText2!
                                     .copyWith(fontSize: 16)),
                             Text(
                               audioObject.subtitle,
                               style: Theme.of(context)
                                   .textTheme
-                                  .bodyText2
+                                  .bodyText2!
                                   .copyWith(
                                       color: Colors.black.withOpacity(0.55)),
                             ),

lib/miniplayer.dart

@@ -37,24 +37,24 @@ class Miniplayer extends StatefulWidget {
 
   ///Allows you to use a global ValueNotifier with the current progress.
   ///This can be used to hide the BottomNavigationBar.
-  final ValueNotifier<double> valueNotifier;
+  final ValueNotifier<double>? valueNotifier;
 
   ///Deprecated
   @Deprecated(
       "Migrate onDismiss to onDismissed as onDismiss will be used differently in a future version.")
-  final Function onDismiss;
+  final Function? onDismiss;
 
   ///If onDismissed is set, the miniplayer can be dismissed
-  final Function onDismissed;
+  final Function? onDismissed;
 
   //Allows you to manually control the miniplayer in code
-  final MiniplayerController controller;
+  final MiniplayerController? controller;
 
   const Miniplayer({
-    Key key,
+    Key? key,
-    @required this.minHeight,
+    required this.minHeight,
-    @required this.maxHeight,
+    required this.maxHeight,
-    @required this.builder,
+    required this.builder,
     this.curve = Curves.easeOut,
     this.elevation = 0,
     this.backgroundColor = const Color(0x70000000),
@@ -70,17 +70,17 @@ class Miniplayer extends StatefulWidget {
 }
 
 class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
-  ValueNotifier<double> heightNotifier;
+  late ValueNotifier<double> heightNotifier;
   ValueNotifier<double> dragDownPercentage = ValueNotifier(0);
 
   ///Temporary variable as long as onDismiss is deprecated. Will be removed in a future version.
-  Function onDismissed;
+  Function? onDismissed;
 
   ///Current y position of drag gesture
-  double _dragHeight;
+  late double _dragHeight;
 
   ///Used to determine SnapPosition
-  double _startHeight;
+  late double _startHeight;
 
   bool dismissed = false;
 
@@ -91,19 +91,19 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
 
   StreamController<double> _heightController =
       StreamController<double>.broadcast();
-  AnimationController _animationController;
+  AnimationController? _animationController;
 
   void _statusListener(AnimationStatus status) {
     if (status == AnimationStatus.completed) _resetAnimationController();
   }
 
-  void _resetAnimationController({Duration duration}) {
+  void _resetAnimationController({Duration? duration}) {
-    if (_animationController != null) _animationController.dispose();
+    if (_animationController != null) _animationController!.dispose();
     _animationController = AnimationController(
       vsync: this,
-      duration: duration == null ? widget.duration : duration,
+      duration: duration ?? widget.duration,
     );
-    _animationController.addStatusListener(_statusListener);
+    _animationController!.addStatusListener(_statusListener);
     animating = false;
   }
 
@@ -112,14 +112,14 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
     if (widget.valueNotifier == null)
       heightNotifier = ValueNotifier(widget.minHeight);
     else
-      heightNotifier = widget.valueNotifier;
+      heightNotifier = widget.valueNotifier!;
 
     _resetAnimationController();
 
     _dragHeight = heightNotifier.value;
 
     if (widget.controller != null)
-      widget.controller.addListener(controllerListener);
+      widget.controller!.addListener(controllerListener);
 
     if (widget.onDismissed != null)
       onDismissed = widget.onDismissed;
@@ -133,10 +133,10 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
   @override
   void dispose() {
     _heightController.close();
-    _animationController.dispose();
+    if (_animationController != null) _animationController!.dispose();
 
     if (widget.controller != null)
-      widget.controller.removeListener(controllerListener);
+      widget.controller!.removeListener(controllerListener);
 
     super.dispose();
   }
@@ -154,8 +154,9 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
         return true;
       },
       child: ValueListenableBuilder(
-        builder: (BuildContext context, double value, Widget child) {
+        valueListenable: heightNotifier,
-          var _percentage = ((value - widget.minHeight)) /
+        builder: (BuildContext context, double height, Widget? _) {
+          var _percentage = ((height - widget.minHeight)) /
               (widget.maxHeight - widget.minHeight);
 
           return Stack(
@@ -173,12 +174,13 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
               Align(
                 alignment: Alignment.bottomCenter,
                 child: SizedBox(
-                  height: value,
+                  height: height,
                   child: GestureDetector(
                     child: ValueListenableBuilder(
                       valueListenable: dragDownPercentage,
-                      builder: (context, value, child) {
+                      builder:
-                        if (value == 0) return child;
+                          (BuildContext context, double value, Widget? child) {
+                        if (value == 0) return child!;
 
                         return Opacity(
                           opacity: borderDouble(
@@ -193,7 +195,7 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
                         color: Theme.of(context).canvasColor,
                         child: Container(
                           constraints: BoxConstraints.expand(),
-                          child: widget.builder(value, _percentage),
+                          child: widget.builder(height, _percentage),
                           decoration: BoxDecoration(
                             boxShadow: <BoxShadow>[
                               BoxShadow(
@@ -278,7 +280,6 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
             ],
           );
         },
-        valueListenable: heightNotifier,
       ),
     );
   }
@@ -306,7 +307,7 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
         dragDownPercentage.value = percentageDown;
 
       if (percentageDown >= 1 && animation && !dismissed) {
-        if (onDismissed != null) onDismissed();
+        if (onDismissed != null) onDismissed!();
         setState(() {
           dismissed = true;
         });
@@ -330,7 +331,8 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
   }
 
   ///Animates the panel height to a specific value
-  void _animateToHeight(final double h, {Duration duration}) {
+  void _animateToHeight(final double h, {Duration? duration}) {
+    if (_animationController == null) return;
     final startHeight = _dragHeight;
 
     if (duration != null) _resetAnimationController(duration: duration);
@@ -339,7 +341,7 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
       begin: startHeight,
       end: h,
     ).animate(
-        CurvedAnimation(parent: _animationController, curve: widget.curve));
+        CurvedAnimation(parent: _animationController!, curve: widget.curve));
 
     _sizeAnimation.addListener(() {
       if (_sizeAnimation.value == startHeight) return;
@@ -350,34 +352,37 @@ class _MiniplayerState extends State<Miniplayer> with TickerProviderStateMixin {
     });
 
     animating = true;
-    _animationController.forward(from: 0);
+    _animationController!.forward(from: 0);
   }
 
   //Listener function for the controller
   void controllerListener() {
-    switch (widget.controller.value.height) {
+    if (widget.controller == null) return;
+    if (widget.controller!.value == null) return;
+
+    switch (widget.controller!.value!.height) {
       case -1:
         _animateToHeight(
           widget.minHeight,
-          duration: widget.controller.value.duration,
+          duration: widget.controller!.value!.duration,
         );
         break;
       case -2:
         _animateToHeight(
           widget.maxHeight,
-          duration: widget.controller.value.duration,
+          duration: widget.controller!.value!.duration,
         );
         break;
       case -3:
         _animateToHeight(
           0,
-          duration: widget.controller.value.duration,
+          duration: widget.controller!.value!.duration,
         );
         break;
       default:
         _animateToHeight(
-          widget.controller.value.height.toDouble(),
+          widget.controller!.value!.height.toDouble(),
-          duration: widget.controller.value.duration,
+          duration: widget.controller!.value!.duration,
         );
         break;
     }
@@ -390,29 +395,30 @@ enum PanelState { MAX, MIN, DISMISS }
 //ControllerData class. Used for the controller
 class ControllerData {
   final int height;
-  final Duration duration;
+  final Duration? duration;
 
   const ControllerData(this.height, this.duration);
 }
 
 //MiniplayerController class
-class MiniplayerController extends ValueNotifier<ControllerData> {
+class MiniplayerController extends ValueNotifier<ControllerData?> {
   MiniplayerController() : super(null);
 
   //Animates to a given height or state(expanded, dismissed, ...)
-  void animateToHeight({double height, PanelState state, Duration duration}) {
+  void animateToHeight(
+      {double? height, PanelState? state, Duration? duration}) {
     if (height == null && state == null)
       throw ("Miniplayer: One of the two parameters, height or status, is required.");
 
     if (height != null && state != null)
       throw ("Miniplayer: Only one of the two parameters, height or status, can be specified.");
 
-    ControllerData valBefore = value;
+    ControllerData? valBefore = value;
 
     if (state != null)
       value = ControllerData(state.heightCode, duration);
     else {
-      if (height < 0) return;
+      if (height! < 0) return;
 
       value = ControllerData(height.round(), duration);
     }

lib/src/miniplayer_will_pop_scope.dart

@@ -2,11 +2,10 @@ import 'package:flutter/material.dart';
 
 class MiniplayerWillPopScope extends StatefulWidget {
   const MiniplayerWillPopScope({
-    Key key,
+    Key? key,
-    @required this.child,
+    required this.child,
-    @required this.onWillPop,
+    required this.onWillPop,
-  })  : assert(child != null),
+  }) : super(key: key);
-        super(key: key);
 
   final Widget child;
   final WillPopCallback onWillPop;
@@ -14,15 +13,15 @@ class MiniplayerWillPopScope extends StatefulWidget {
   @override
   _MiniplayerWillPopScopeState createState() => _MiniplayerWillPopScopeState();
 
-  static _MiniplayerWillPopScopeState of(BuildContext context) {
+  static _MiniplayerWillPopScopeState? of(BuildContext context) {
     return context.findAncestorStateOfType<_MiniplayerWillPopScopeState>();
   }
 }
 
 class _MiniplayerWillPopScopeState extends State<MiniplayerWillPopScope> {
-  ModalRoute<dynamic> _route;
+  ModalRoute<dynamic>? _route;
 
-  _MiniplayerWillPopScopeState _descendant;
+  _MiniplayerWillPopScopeState? _descendant;
 
   set descendant(state) {
     _descendant = state;
@@ -30,11 +29,11 @@ class _MiniplayerWillPopScopeState extends State<MiniplayerWillPopScope> {
   }
 
   Future<bool> onWillPop() async {
-    bool willPop;
+    bool? willPop;
     if (_descendant != null) {
-      willPop = await _descendant.onWillPop();
+      willPop = await _descendant!.onWillPop();
     }
-    if (willPop == null || willPop) {
+    if (willPop == null) {
       willPop = await widget.onWillPop();
     }
     return willPop;

lib/src/utils.dart

@@ -16,11 +16,11 @@ extension SelectedColorExtension on PanelState {
 }
 
 ///Calculates the percentage of a value within a given range of values
-double percentageFromValueInRange({final double min, max, value}) {
+double percentageFromValueInRange({required double min, max, value}) {
   return (value - min) / (max - min);
 }
 
-double borderDouble({double minRange, double maxRange, double value}) {
+double borderDouble({required double minRange, maxRange, value}) {
   if (value > maxRange) return maxRange;
   if (value < minRange) return minRange;
   return value;

pubspec.yaml

@@ -5,8 +5,8 @@ homepage: https://www.peterscode.dev
 repository: https://github.com/peterscodee/miniplayer
 
 environment:
-  sdk: ">=2.6.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=1.0.0 <2.0.0"
+  flutter: ">=2.0.1 <3.0.0"
 
 dependencies:
   flutter: