demo中使用FlutterBoostApp包裹的 appBuilder, 怎么指定自己的widget ???

[ke112]

Widget appBuilder(Widget home) { return MaterialApp( home: home, debugShowCheckedModeBanner: false,

  ///必须加上builder参数，否则showDialog等会出问题
  builder: (_, __) {
    return home;
  },
);

}

@override Widget build(BuildContext context) { return FlutterBoostApp( routeFactory, appBuilder: appBuilder, ); }

如上,是demo的写法...我自己的项目,,我把appBuilder内的 home 改成自己的根widget,为何 一运行 ,代码就报错...

======== Exception caught by scheduler library ===================================================== The following _CastError was thrown during a scheduler callback: Null check operator used on a null value

When the exception was thrown, this was the stack: #0 BoostChannel.addEventListener (package:flutter_boost/src/boost_channel.dart:32:21) #1 FlutterBoostAppState._addAppLifecycleStateEventListener (package:flutter_boost/src/flutter_boost_app.dart:119:10) #2 FlutterBoostAppState.initState. (package:flutter_boost/src/flutter_boost_app.dart:108:7) #3 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1145:15) #4 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1090:9) #5 SchedulerBinding.scheduleWarmUpFrame. (package:flutter/src/scheduler/binding.dart:863:7) (elided 11 frames from class _RawReceivePortImpl, class _Timer, dart:async, and dart:async-patch)

这怎么办???