BUG: _TypeError (Null check operator used on a null value)

[bhawesh2002]

🐛 Describe the bug

The following exception was thrown when launching the app on device using API 34: _TypeError (Null check operator used on a null value)

═══════ Exception caught by widgets library ═══════════════════════════════════
The following _TypeError was thrown building MyApp(dirty):
Null check operator used on a null value

The relevant error-causing widget was:
    MyApp MyApp:file:///E:/FlutterProjects/Resonate/lib/main.dart:33:16

When the exception was thrown, this was the stack:
#0      GetNavigation.window (package:get/get_navigation/src/extension_navigation.dart:1169:44)
extension_navigation.dart:1169
#1      GetNavigation.size (package:get/get_navigation/src/extension_navigation.dart:1176:20)
extension_navigation.dart:1176
#2      GetNavigation.width (package:get/get_navigation/src/extension_navigation.dart:1179:23)
extension_navigation.dart:1179
#3      UiSizes.size_56 (package:resonate/utils/ui_sizes.dart:119:39)
ui_sizes.dart:119
#4      UiSizes.size_56 (package:resonate/utils/ui_sizes.dart)
#5      Themes.lightTheme (package:resonate/themes/themes.dart:25:30)
themes.dart:25
#6      Themes.lightTheme (package:resonate/themes/themes.dart)
#7      MyApp.build (package:resonate/main.dart:51:21)
main.dart:51
#8      StatelessElement.build (package:flutter/src/widgets/framework.dart:5550:49)
framework.dart:5550
#9      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5480:15)
framework.dart:5480
#10     Element.rebuild (package:flutter/src/widgets/framework.dart:5196:7)
framework.dart:5196
#11     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:5462:5)
framework.dart:5462
#12     ComponentElement.mount (package:flutter/src/widgets/framework.dart:5456:5)
framework.dart:5456
...     Normal element mounting (27 frames)
#39     Element.inflateWidget (package:flutter/src/widgets/framework.dart:4335:16)
framework.dart:4335
#40     Element.updateChild (package:flutter/src/widgets/framework.dart:3846:18)
framework.dart:3846
#41     _RawViewElement._updateChild (package:flutter/src/widgets/view.dart:291:16)
view.dart:291
#42     _RawViewElement.mount (package:flutter/src/widgets/view.dart:314:5)
view.dart:314
...     Normal element mounting (7 frames)
#49     Element.inflateWidget (package:flutter/src/widgets/framework.dart:4335:16)
framework.dart:4335
#50     Element.updateChild (package:flutter/src/widgets/framework.dart:3846:18)
framework.dart:3846
#51     RootElement._rebuild (package:flutter/src/widgets/binding.dart:1354:16)
binding.dart:1354
#52     RootElement.mount (package:flutter/src/widgets/binding.dart:1323:5)
binding.dart:1323
#53     RootWidget.attach.<anonymous closure> (package:flutter/src/widgets/binding.dart:1276:18)
binding.dart:1276
#54     BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2844:19)
framework.dart:2844
#55     RootWidget.attach (package:flutter/src/widgets/binding.dart:1275:13)
binding.dart:1275
#56     WidgetsBinding.attachToBuildOwner (package:flutter/src/widgets/binding.dart:1088:27)
binding.dart:1088
#57     WidgetsBinding.attachRootWidget (package:flutter/src/widgets/binding.dart:1070:5)
binding.dart:1070
#58     WidgetsBinding.scheduleAttachRootWidget.<anonymous closure> (package:flutter/src/widgets/binding.dart:1056:7)
binding.dart:1056
#62     _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)
(elided 3 frames from class _Timer and dart:async-patch)

Here is the screenshot:

[AyaNady17]

I'm facing the same problem. could you find a solution? @bhawesh2002

[bhawesh2002]

The exception is throwned becaues context is not available to Get package when Get.width is encountered. Some of my other flutter apps face the same issue when Get is used before the context is completely available. We use Themes.lightTheme as ThemeData for themeproperty of GetMaterialApp. This is when Get is first used. Themes.lightTheme has the toolbarHeightproperty of the appBarTheme which uses UiSizes.size_56. So when static double size_56 = 0.068 * Get.width + 0.034 * Get.height; is encountered the contextis not fully available and _TypeError (Null check operator used on a null value) exception is throwned.

[bhawesh2002]

Another thing to note here is that if we just comment out the properties of themeand darkThemeof GetMaterialApp which after making changes should look like this:

GetMaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Resonate',
      //theme: Themes.lightTheme,
      //darkTheme: Themes.darkTheme,
      themeMode: themeController.theme,
      initialRoute: AppRoutes.splash,
      getPages: AppPages.pages,
    );

The _TypeError (Null check operator used on a null value) is not throwned and everything works fine.

This implies that there is some issue faced by Getpackage to obtain values of width,height etc. when Themes.lightTheme is used as ThemeData for the property theme as any other codefiles using Getpackage for width,height etc work completely fine.

[bhawesh2002]

@chandansgowda @Aarush-Acharya Is there any way we could deal with this.

Another thing to note here is that if we just comment out the properties of themeand darkThemeof GetMaterialApp which after making changes should look like this:

GetMaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Resonate',
      //theme: Themes.lightTheme,
      //darkTheme: Themes.darkTheme,
      themeMode: themeController.theme,
      initialRoute: AppRoutes.splash,
      getPages: AppPages.pages,
    );

The _TypeError (Null check operator used on a null value) is not throwned and everything works fine.

This implies that there is some issue faced by Getpackage to obtain values of width,height etc. when Themes.lightTheme is used as ThemeData for the property theme as any other codefiles using Getpackage for width,height etc work completely fine.