Getting error in the initState()

[shubham26794]

I am getting this error:

════════ Exception caught by scheduler library ═════════════════════════════════
The following NoSuchMethodError was thrown during a scheduler callback:
The method 'findRenderObject' was called on null.
Receiver: null
Tried calling: findRenderObject()

When the exception was thrown, this was the stack
#0      Object.noSuchMethod (dart:core-patch/object_patch.dart:54:5)
#1      SlideToActState.initState.<anonymous closure> (package:eagl/widgets/slide_to_act.dart:372:40)
#2      SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1144:15)
#3      SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1090:9)
#4      SchedulerBinding.scheduleWarmUpFrame.<anonymous closure> (package:flutter/src/scheduler/binding.dart:865:7)