问颤动错误:在AnimationController.dispose()之后调用AnimationController.stop()

EN

class MyApp extends StatelessWidget {

  ThemeData myTheme;
  bool isDark;
  @override
  Widget build(BuildContext context) {
    isDark=false;
    return FutureBuilder(
      future: getTheme(),
      builder: (context,snapshot) {
        if (snapshot.hasData) {
          if(isDark)
            myTheme=Constants.darkTheme;
          else
            myTheme=Constants.lightTheme;
          return MaterialApp(
            title: 'Sample app',
            debugShowCheckedModeBanner: false,
            theme: myTheme,
            home: HomePage(),
          );
        }
        return MaterialApp(
          title: 'Sample app',
          debugShowCheckedModeBanner: false,
          home: Scaffold(body: Center(child: Text('Loading')),),
        );
      },
    );
  }
  Future<bool> getTheme() async  {
    SharedPreferences sharedPreferences =  await SharedPreferences.getInstance() ;
    isDark=sharedPreferences.getBool("isDark");
    if(isDark==null) {
      isDark=false;
      sharedPreferences.setBool("isDark", isDark);
    }
    return isDark;
  }
}

E/flutter ( 5809): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: 'package:flutter/src/animation/animation_controller.dart': Failed assertion: line 741 pos 7: '_ticker != null': AnimationController.stop() called after AnimationController.dispose()
E/flutter ( 5809): AnimationController methods should not be used after calling dispose.
E/flutter ( 5809): #0      _AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:46:39)
E/flutter ( 5809): #1      _AssertionError._throwNew (dart:core-patch/errors_patch.dart:36:5)
E/flutter ( 5809): #2      AnimationController.stop (package:flutter/src/animation/animation_controller.dart:741:7)
E/flutter ( 5809): #3      AnimationController.repeat (package:flutter/src/animation/animation_controller.dart:637:5)
E/flutter ( 5809): #4      BallPulseIndicator.startAnim (package:loading/indicator/ball_pulse_indicator.dart:48:16)
E/flutter ( 5809): #5      BallPulseIndicator.startAnims.<anonymous closure> (package:loading/indicator/ball_pulse_indicator.dart:55:9)
E/flutter ( 5809): #6      new Future.delayed.<anonymous closure> (dart:async/future.dart:326:39)
E/flutter ( 5809): #7      _rootRun (dart:async/zone.dart:1182:47)
E/flutter ( 5809): #8      _CustomZone.run (dart:async/zone.dart:1093:19)
E/flutter ( 5809): #9      _CustomZone.runGuarded (dart:async/zone.dart:997:7)
E/flutter ( 5809): #10     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1037:23)
E/flutter ( 5809): #11     _rootRun (dart:async/zone.dart:1190:13)
E/flutter ( 5809): #12     _CustomZone.run (dart:async/zone.dart:1093:19)
E/flutter ( 5809): #13     _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:1021:23)
E/flutter ( 5809): #14     Timer._createTimer.<anonymous closure> (dart:async-patch/timer_patch.dart:18:15)
E/flutter ( 5809): #15     _Timer._runTimers (dart:isolate-patch/timer_impl.dart:397:19)
E/flutter ( 5809): #16     _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:428:5)
E/flutter ( 5809): #17     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:168:12)