title: shared Preferences in flutter stop the app
body: <p>I'm calling shared prefs in page I made as splash screen</p>
  <pre><code>  void initState() {
      super.initState();
      getPreferences().then((value){
        Timer(
          Duration(seconds: 2),
          (() =&gt; {
            Navigator.of(context).pushReplacement(new MaterialPageRoute(
                builder: (BuildContext context) =&gt; value))
          }),
        );
      });
    }
  
  </code></pre>
  <p>and here is my method</p>
  <pre><code>   getPreferences() async {
      WidgetsFlutterBinding.ensureInitialized();//??**
      SharedPreferences prefs = await SharedPreferences.getInstance();//the same with home screen in the skip button
      bool loadingScreen=prefs.getBool('seen');
      print(&quot;loadingScreen = $loadingScreen&quot;);
      StatefulWidget _screen= LoginScr();
       if (loadingScreen == null|| loadingScreen == false){
         _screen = Tut();
       }
       else if (loadingScreen == true){
         userName = prefs.getString('userName');
         if(userName ==null||userName==&quot;null&quot;) {
           print(userName+' userName in main');
           _screen = LoginScr();
         } else {
           print(userName +'userName in main');
           _screen = HomePage();
         }
       }
       return _screen;
    }
  </code></pre>
  <p>By the way I don't know what is this line
  <code>Widge,tsFlutterBinding.ensureInitialized();</code>//??**
  and here is my log</p>
  <blockquote>
  <p>Performing hot restart... Syncing files to device Android SDK built
  for x86... Restarted application in 1,776ms. I/flutter ( 8982):
  loadingScreen = true E/flutter ( 8982):
  [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception:
  NoSuchMethodError: The method '+' was called on null. E/flutter (
  8982): Receiver: null E/flutter ( 8982): Tried calling: +(&quot; userName
  in main&quot;) E/flutter ( 8982): #0      Object.noSuchMethod
  (dart:core-patch/object_patch.dart:51:5) E/flutter ( 8982): #1<br />
  _SplashSCRState.getPreferences (package:plaster/UI/SplashSCR.dart:138:24) E/flutter ( 8982):
   E/flutter ( 8982): #2<br />
  _SplashSCRState.initState (package:plaster/UI/SplashSCR.dart:26:5) E/flutter ( 8982): #3      StatefulElement._firstBuild
  (package:flutter/src/widgets/framework.dart:4765:58) E/flutter (
  8982): #4      ComponentElement.mount
  (package:flutter/src/widgets/framework.dart:4601:5) E/flutter ( 8982):
  #5      Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14) E/flutter (
  8982): #6      Element.updateChild
  (package:flutter/src/widgets/framework.dart:3327:18) E/flutter (
  8982): #7      SingleChildRenderObjectElement.mount
  (package:flutter/src/widgets/framework.dart:6118:14) E/flutter (
  8982): #8      Element.inflateWidget
  (package:flutter/src/widgets/framework.dart:3569:14) E/flutter (
  8982): #9      Element.updateChild
  (package:flutter/src/widgets/framework.dart:3327:18) E/flutter (
  8982): #10     ComponentElement.performRebuild
  (package:flutter/src/widgets/framework.dart:4652:16) E/flutter (
  8982): #11     Element.rebuild
  (package:flutter/src/widgets/framework.dart:4343:5) E/flutter ( 8982):
  #12     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5) E/flutter ( 8982):
  #13     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5) E/flutter ( 8982):
  #14     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14) E/flutter (
  8982): #15     Element.updateChild
  (package:flutter/src/widgets/framework.dart:3327:18) E/flutter (
  8982): #16     SingleChildRenderObjectElement.mount
  (package:flutter/src/widgets/framework.dart:6118:14) E/flutter (
  8982): #17     Element.inflateWidget
  (package:flutter/src/widgets/framework.dart:3569:14) E/flutter (
  8982): #18     Element.updateChild
  (package:flutter/src/widgets/framework.dart:3327:18) E/flutter (
  8982): #19     SingleChildRenderObjectElement.mount
  (package:flutter/src/widgets/framework.dart:6118:14) E/flutter (
  8982): #20     Element.inflateWidget
  (package:flutter/src/widgets/framework.dart:3569:14) E/flutter (
  8982): #21     Element.updateChild
  (package:flutter/src/widgets/framework.dart:3327:18) E/flutter (
  8982): #22     ComponentElement.performRebuild
  (package:flutter/src/widgets/framework.dart:4652:16) E/flutter (
  8982): #23     StatefulElement.performRebuild
  (package:flutter/src/widgets/framework.dart:4800:11) E/flutter (
  8982): #24     Element.rebuild
  (package:flutter/src/widgets/framework.dart:4343:5) E/flutter ( 8982):
  #25     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5) E/flutter ( 8982):
  #26     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4791:11) E/flutter (
  8982): #27     ComponentElement.mount
  (package:flutter/src/widgets/framework.dart:4601:5) E/flutter ( 8982):
  #28     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14) E/flutter (
  8982): #29     Element.updateChild
  (package:flutter/src/widgets/framework.dart:3327:18) E/flutter (
  8982): #30     SingleChildRenderObjectElement.mount
  (package:flutter/src/widgets/framework.dart:6118:14) E/flutter (
  8982): #31     Element.inflateWidget
  (package:flutter/src/widgets/framework.dart:3569:14) E/flutter (
  8982): #32     Element.updateChild
  (package:flutter/src/widgets/framework.dart:3327:18) E/flutter (
  8982): #33     SingleChildRenderObjectElement.mount
  (package:flutter/src/widgets/framework.dart:6118:14) E/flutter (
  8982): #34     Element.inflateWidget
  (package:flutter/src/widgets/framework.dart:3569:14) E/flutter (
  8982): #35     Element.updateChild
  (package:flutter/src/widgets/framework.dart:3327:18) E/flutter (
  8982): #36     ComponentElement.performRebuild
  (package:flutter/src/widgets/framework.dart:4652:16) E/flutter (
  8982): #37     StatefulElement.performRebuild
  (package:flutter/src/widgets/framework.dart:4800:11) E/flutter (
  8982): #38     Element.rebuild
  (package:flutter/src/widgets/framework.dart:4343:5) E/flutter ( 8982):
  #39     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5) E/flutter ( 8982):
  #40     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4791:11) E/flutter (
  8982): #41     ComponentElement.mount
  (package:flutter/src/widgets/framework.dart:4601:5) E/flutter ( 8982):
  #42     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14) E/flutter (
  8982): #43     Element.updateChild
  (package:flutter/src/widgets/framework.dart:3327:18) E/flutter (
  8982): #44     ComponentElement.performRebuild
  (package:flutter/src/widgets/framework.dart:4652:16) E/flutter (
  8982): #45     Element.r</p>
  </blockquote>