Help!! NoSuchMethodError: The method '>' was called on null #43980

I want to realise Schulte grid , This is my code:

import 'package:flutter/material.dart';

void main(){
runApp(MyApp());
}

class MyApp extends StatelessWidget{
const MyApp({Key key} ) : super(key: key);

Widget build(BuildContext context) {
return MaterialApp(
title: "Schulte grid",
home: SchulteCell(),
);
}
}

class SchulteCell extends StatefulWidget{
SchulteCell({Key key}) : super(key: key);

_SchulteCellState createState() => _SchulteCellState();
}

class _SchulteCellState extends Statewith TickerProviderStateMixin{
int count;
List data=List();
List curSel=List();
List controllers=List();
List<Animation> animations=List<Animation>();

void iniState() {
super.initState();
count=16;
List.generate(count, (index){
data.add(index+1);
controllers.add(AnimationController(
vsync:this, duration: Duration(milliseconds: 600)));
animations.add(
ColorTween(begin: Colors.white, end: Colors. purpleAccent)
.animate(controllers[index])..addListener((){
setState(() {

          });
    })
  );
});
data.shuffle();

}

tapCell(i){
int lastSel= curSel.length>0?curSel.last:0;
if(data[i]-1==lastSel) {
animations[i] = ColorTween(begin: Colors.white, end: Colors.purpleAccent)
.animate(controllers[i])
..addListener(() {
setState(() {

      });
    });
  curSel.add(data[i]);
}
else{
  animations[i] = ColorTween(begin: Colors.white, end: Colors.redAccent)
      .animate(controllers[i])
    ..addListener(() {
      setState(() {

      });
    });



}
controllers[i].forward(from: 0).then((_)=>controllers[i].reverse());

}

Widget build(BuildContext context){
return Scaffold(
appBar: AppBar(title: Text("Schulte grid"),),
body: GridView.count(
crossAxisCount: 4,
children:
List.generate(
count, (index) => Container(
alignment: Alignment.center,
decoration: BoxDecoration(border: Border.all(width: 1),
color: animations[index].value),
child: FlatButton(
onPressed: (){tapCell(index);},
child: Text(
"${data[index]}",
style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),

),

)
      ))),
);

}
}

AND THE IntelliJ demonstrates:

Performing hot restart...
Syncing files to device iPhone Xʀ...
Restarted application in 1,346ms.
flutter: ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
flutter: The following NoSuchMethodError was thrown building SchulteCell(dirty, state:
flutter: _SchulteCellState#4352f):
flutter: The method '>' was called on null.
flutter: Receiver: null
flutter: Tried calling: >(0)
flutter:
flutter: When the exception was thrown, this was the stack:
flutter: #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:50:5)
flutter: #1 List.length= (dart:core-patch/growable_array.dart:119:22)
flutter: #2 new List.generate (dart:core/list.dart:158:23)
flutter: #3 _SchulteCellState.build (package:untitled/main.dart:86:16)
flutter: #4 StatefulElement.build (package:flutter/src/widgets/framework.dart:4012:27)
flutter: #5 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3924:15)
flutter: #6 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #7 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #8 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #9 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #10 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #11 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #12 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #13 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #14 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #15 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #16 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #17 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #18 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #19 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #20 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #21 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #22 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #23 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #24 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #25 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #26 MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5198:32)
flutter: #27 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #28 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #29 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #30 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #31 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #32 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #33 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #34 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #35 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #36 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #37 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #38 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #39 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #40 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #41 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #42 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #43 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #44 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #45 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #46 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #47 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #48 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #49 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #50 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #51 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #52 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #53 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #54 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #55 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #56 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #57 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #58 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #59 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #60 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #61 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #62 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #63 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #64 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #65 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #66 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #67 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #68 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #69 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #70 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #71 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #72 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #73 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #74 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #75 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #76 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #77 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #78 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #79 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #80 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #81 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #82 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #83 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #84 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #85 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #86 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #87 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #88 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #89 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #90 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #91 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #92 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #93 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #94 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #95 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #96 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #97 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #98 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #99 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #100 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #101 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #102 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #103 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #104 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #105 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #106 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #107 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #108 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #109 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #110 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #111 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #112 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #113 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #114 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #115 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #116 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #117 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #118 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #119 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #120 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #121 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #122 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #123 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #124 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #125 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #126 MultiChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5198:32)
flutter: #127 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #128 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #129 _TheatreElement.mount (package:flutter/src/widgets/overlay.dart:593:16)
flutter: #130 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #131 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #132 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #133 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #134 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #135 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #136 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #137 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #138 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #139 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #140 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #141 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #142 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #143 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #144 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #145 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #146 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #147 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #148 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #149 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #150 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #151 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #152 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #153 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #154 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #155 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #156 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #157 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #158 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #159 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #160 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #161 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #162 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #163 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #164 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #165 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #166 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #167 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #168 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #169 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #170 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #171 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #172 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #173 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #174 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #175 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #176 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #177 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #178 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #179 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #180 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #181 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #182 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #183 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #184 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #185 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #186 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #187 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #188 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #189 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #190 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #191 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #192 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #193 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #194 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #195 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #196 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #197 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #198 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #199 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #200 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #201 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #202 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #203 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #204 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #205 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #206 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #207 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #208 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #209 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #210 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #211 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #212 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #213 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #214 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #215 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #216 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #217 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #218 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #219 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #220 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #221 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #222 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #223 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #224 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #225 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #226 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #227 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #228 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #229 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #230 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #231 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #232 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #233 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #234 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #235 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #236 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #237 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #238 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #239 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #240 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #241 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #242 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #243 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #244 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #245 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #246 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #247 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #248 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #249 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #250 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #251 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #252 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #253 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #254 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #255 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #256 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5092:14)
flutter: #257 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #258 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #259 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #260 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #261 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #262 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #263 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #264 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #265 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #266 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #267 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #268 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #269 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #270 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #271 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #272 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #273 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #274 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #275 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #276 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #277 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #278 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #279 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #280 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #281 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #282 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #283 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #284 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #285 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #286 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #287 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #288 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #289 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #290 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #291 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #292 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #293 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #294 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4053:11)
flutter: #295 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #296 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #297 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #298 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #299 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #300 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3907:5)
flutter: #301 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3902:5)
flutter: #302 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3084:14)
flutter: #303 Element.updateChild (package:flutter/src/widgets/framework.dart:2887:12)
flutter: #304 RenderObjectToWidgetElement._rebuild (package:flutter/src/widgets/binding.dart:939:16)
flutter: #305 RenderObjectToWidgetElement.mount (package:flutter/src/widgets/binding.dart:910:5)
flutter: #306 RenderObjectToWidgetAdapter.attachToRenderTree. (package:flutter/src/widgets/binding.dart:856:17)
flutter: #307 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2320:19)
flutter: #308 RenderObjectToWidgetAdapter.attachToRenderTree (package:flutter/src/widgets/binding.dart:855:13)
flutter: #309 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.attachRootWidget (package:flutter/src/widgets/binding.dart:736:7)
flutter: #310 runApp (package:flutter/src/widgets/binding.dart:786:7)
flutter: #311 main (package:untitled/main.dart:5:3)
flutter: #312 _runMainZoned.. (dart:ui/hooks.dart:216:25)
flutter: #317 _runMainZoned. (dart:ui/hooks.dart:208:5)
flutter: #318 _startIsolate. (dart:isolate-patch/isolate_patch.dart:301:19)
flutter: #319 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:172:12)
flutter: (elided 4 frames from package dart:async)
flutter: ════════════════════════════════════════════════════════════════════════════════════════════════════
flutter: ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
flutter: The following NoSuchMethodError was thrown building SchulteCell(dirty, state:
flutter: _SchulteCellState#4352f):
flutter: The method '>' was called on null.
flutter: Receiver: null
flutter: Tried calling: >(0)
flutter:
flutter: When the exception was thrown, this was the stack:
flutter: #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:50:5)
flutter: #1 List.length= (dart:core-patch/growable_array.dart:119:22)
flutter: #2 new List.generate (dart:core/list.dart:158:23)
flutter: #3 _SchulteCellState.build (package:untitled/main.dart:86:16)
flutter: #4 StatefulElement.build (package:flutter/src/widgets/framework.dart:4012:27)
flutter: #5 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3924:15)
flutter: #6 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #7 StatefulElement.update (package:flutter/src/widgets/framework.dart:4085:5)
flutter: #8 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #9 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5099:14)
flutter: #10 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #11 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #12 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #13 StatelessElement.update (package:flutter/src/widgets/framework.dart:3981:5)
flutter: #14 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #15 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5099:14)
flutter: #16 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #17 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5099:14)
flutter: #18 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #19 RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:4817:32)
flutter: #20 MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5208:17)
flutter: #21 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #22 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #23 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #24 StatefulElement.update (package:flutter/src/widgets/framework.dart:4085:5)
flutter: #25 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #26 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5099:14)
flutter: #27 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #28 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #29 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #30 StatefulElement.update (package:flutter/src/widgets/framework.dart:4085:5)
flutter: #31 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #32 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5099:14)
flutter: #33 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #34 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #35 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #36 StatefulElement.update (package:flutter/src/widgets/framework.dart:4085:5)
flutter: #37 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #38 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5099:14)
flutter: #39 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #40 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #41 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #42 StatefulElement.update (package:flutter/src/widgets/framework.dart:4085:5)
flutter: #43 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #44 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #45 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #46 StatelessElement.update (package:flutter/src/widgets/framework.dart:3981:5)
flutter: #47 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #48 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #49 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #50 StatefulElement.update (package:flutter/src/widgets/framework.dart:4085:5)
flutter: #51 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #52 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5099:14)
flutter: #53 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #54 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #55 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #56 ProxyElement.update (package:flutter/src/widgets/framework.dart:4219:5)
flutter: #57 _InheritedNotifierElement.update (package:flutter/src/widgets/inherited_notifier.dart:94:11)
flutter: #58 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #59 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5099:14)
flutter: #60 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #61 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #62 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #63 StatefulElement.update (package:flutter/src/widgets/framework.dart:4085:5)
flutter: #64 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #65 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #66 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #67 StatelessElement.update (package:flutter/src/widgets/framework.dart:3981:5)
flutter: #68 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #69 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:5099:14)
flutter: #70 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #71 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #72 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #73 ProxyElement.update (package:flutter/src/widgets/framework.dart:4219:5)
flutter: #74 Element.updateChild (package:flutter/src/widgets/framework.dart:2876:15)
flutter: #75 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3935:16)
flutter: #76 Element.rebuild (package:flutter/src/widgets/framework.dart:3721:5)
flutter: #77 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2340:33)
flutter: #78 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:700:20)
flutter: #79 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&SemanticsBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:285:5)
flutter: #80 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1016:15)
flutter: #81 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:958:9)
flutter: #82 _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.scheduleWarmUpFrame. (package:flutter/src/scheduler/binding.dart:784:7)
flutter: #84 _Timer._runTimers (dart:isolate-patch/timer_impl.dart:382:19)
flutter: #85 _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:416:5)
flutter: #86 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:172:12)
flutter: (elided one frame from package dart:async-patch)
flutter: ════════════════════════════════════════════════════════════════════════════════════════════════════