在 flutter getx 中对空值使用的空检查运算符

问题描述

我的代码给出了 Null check operator used on a null value 错误，尽管我在代码中找不到任何空值.

My code is giving the Null check operator used on a null value error although I can't found any null value in the code.

我不知道哪个屏幕实际上导致了错误，但肯定是在这两个屏幕之外

I don't know which screen is actually causing the error but surely it is out of these two screens only which are

1. 启动画面

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:tajicEasy/ui/auth/landingPage.dart';
import 'mySharedPreferences.dart';
import 'onBoarding_page.dart';

class SplashScreen extends StatefulWidget {
  @override
  _SplashScreenState createState() => _SplashScreenState();
}

class _SplashScreenState extends State<SplashScreen> {
  @override
  void initState() {
    super.initState();
    loadSplashScreen();
    myAppState();
  }

  bool isFirstTimeOpen = false;

  myAppState() {
    MySharedPreferences.instance
        .getBooleanValue("firstTimeOpen")
        .then((value) => setState(() {
              isFirstTimeOpen = value;
            }));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      body: Center(
        child: Image.asset(
          "assets/images/logo.png",
          width: double.infinity,
        ),
      ),
    );
  }

  Future<Timer> loadSplashScreen() async {
    return Timer(Duration(seconds: 3), onDoneLoadind);
  }

  onDoneLoadind() async {
    Get.offAll(() => isFirstTimeOpen ? LandingPage() : OnBoardingPage());
  }
}

1. 加载屏幕

import 'package:flutter/cupertino.dart';
import 'package:get/get.dart';
import 'package:tajicEasy/controller/authController.dart';
import 'package:tajicEasy/controller/userController.dart';
import 'package:tajicEasy/ui/auth/login_in.dart';
import 'package:tajicEasy/ui/widgets/bottomNavigationBar.dart';

class LandingPage extends GetWidget<AuthController> {
  @override
  Widget build(BuildContext context){
    return GetX(initState:  maininit(),
        builder: (_) {
      print("here1");
      if (Get.find<AuthController>().user!=null) {
        print("here1");
        return Login();
      } else {
        print("here1");
        return AppMain();
      }
    });
  }

  maininit() {
    print("here");
   Get.put<UserController>(UserController());
    print("here");
    Get.put<AuthController>(AuthController());
    print("here");
  }
}

我尝试将 loadSplashScreen(); 放在 myAppState() 中的 setState 之后但在那之后我得到了同样的错误

I have tried placing loadSplashScreen(); after setState in myAppState()but after that I getting the same error

检查isFirstTimeOpen 是否为空

推荐答案

尝试使用GetWidget在启动屏幕上或使用 globalkey 或两者

try to use GetWidget<'controller'> on splash screen or use globalkey or both

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