Flutter 3.0 shows error : WidgetsBinding.instance!.addPostFrameCallback((_) => widget.onReady.call());

Question

After the upgrade project in flutter 3.0 it shows the following error.

    Syncing files to device iPhone 13 Pro Max...
../../../Developer/flutter/.pub-cache/hosted/pub.dartlang.org/another_transformer_page_view-1.1.0/lib/src/another_transformer_page_view.dart:519:22: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
 - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Developer/flutter/packages/flutter/lib/src/widgets/binding.dart').
      WidgetsBinding.instance!.addPostFrameCallback(_onGetSize);
                     ^
../../../Developer/flutter/.pub-cache/hosted/pub.dartlang.org/another_transformer_page_view-1.1.0/lib/src/another_transformer_page_view.dart:537:22: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
 - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Developer/flutter/packages/flutter/lib/src/widgets/binding.dart').
      WidgetsBinding.instance!.addPostFrameCallback(_onGetSize);
                     ^
../../../Developer/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_login-3.2.0/lib/src/widgets/animated_text.dart:57:20: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
 - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Developer/flutter/packages/flutter/lib/src/widgets/binding.dart').
    WidgetsBinding.instance!.addPostFrameCallback((_) {
                   ^
../../../Developer/flutter/.pub-cache/hosted/pub.dartlang.org/awesome_select-5.2.0/lib/src/widget.dart:1547:58: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
 - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Developer/flutter/packages/flutter/lib/src/widgets/binding.dart').
                MediaQueryData.fromWindow(WidgetsBinding.instance!.window);
                                                         ^
../../../Developer/flutter/.pub-cache/hosted/pub.dartlang.org/awesome_select-5.2.0/lib/src/text_error.dart:99:20: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
 - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../Developer/flutter/packages/flutter/lib/src/widgets/binding.dart').
    WidgetsBinding.instance!.addPostFrameCallback((_) {

it's bug from flutter? Can anyone report this to flutter. i don't know to report this to flutter team.

This Warning bug is resolved. see my comment in correct answer I have written ( if you are a mac user goto finder -> press goto button by swift+cmd+G -> past all 6 files I have mentioned or you find an error and replace [root-name] with your root directory name.

try to do flutter clean , flutter pub update and cd ios and pod install and try — Hardik Mehta, May 19 '22 at 05:33

score 2 · Accepted Answer · answered May 19 '22 at 18:11

2

'WidgetsBinding.instance' getter used to be a nullable type. In the new update it is changed to a Non-nullable. So, now old packages show this after the update because they used null aware operator there. It will be fixed in the new versions. For now you can just remove the null aware operator from the lines that show up in the logs and after rebuild there will be no more warnings.

answered May 19 '22 at 18:11

dewmina udayashan

96
4

Yes, it's just warning i have removed the null operator from each file where the error is showing. – amit.flutter May 20 '22 at 04:58
for mac user press : Swift + window/CMD key + G ( open goto file dialog) and past this files path – amit.flutter May 20 '22 at 05:00
1) /Users/[root-name]/Developer/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_login-3.2.0/lib/src/widgets/animated_text.dart – amit.flutter May 20 '22 at 05:00
2) /Users/[root-name]/Developer/flutter/.pub-cache/hosted/pub.dartlang.org/another_transformer_page_view-1.1.0/lib/src/another_transformer_page_view.dart – amit.flutter May 20 '22 at 05:00
3) /Users/[root-name]/Developer/flutter/.pub-cache/hosted/pub.dartlang.org/awesome_select-5.2.0/lib/src/widget.dart – amit.flutter May 20 '22 at 05:02
4) /Users/[root-name]/Developer/flutter/.pub-cache/hosted/pub.dartlang.org/awesome_select-5.2.0/lib/src/text_error.dart – amit.flutter May 20 '22 at 05:02
5) /Users/[root-Name]/Developer/flutter/.pub-cache/hosted/pub.dartlang.org/awesome_select-5.2.0/lib/src/modal.dart – amit.flutter May 20 '22 at 05:03
6) /Users/[root-name]/Developer/flutter/packages/flutter/lib/src/widgets/binding.dart – amit.flutter May 20 '22 at 05:03

score 0 · Answer 2 · answered May 19 '22 at 06:09

0

it's bug from lib you used in your project, Don't worry. It will fix in next version dependency of lib

Or you can fork code from lib, fix it, and create a pull request to main

example of this issue

use

cached_network_image:
    git:
      url: https://github.com/XuannThucc/flutter_cached_network_image.git
      path: cached_network_image
      ref: ff72f00f142f13d889d7549e013af91cb0b523ab

instead of

cached_network_image: ^3.2.0

or wait for update cached_network_image: ^3.2.1

answered May 19 '22 at 06:09

Xuuan Thuc

2,340
1
5
22

I make changes as per your suggestion but it's not working. Error is still same – amit.flutter May 19 '22 at 07:06
i am already Using: cached_network_image: ^3.2.1 – amit.flutter May 19 '22 at 07:08
these warnings are just warnings. Very annoying, but still compiling and running fine. – Xuuan Thuc May 19 '22 at 07:10
Okay, Thank you. Let me know if there is solution to remove this warning. – amit.flutter May 19 '22 at 07:12

Flutter 3.0 shows error : WidgetsBinding.instance!.addPostFrameCallback((_) => widget.onReady.call());

2 Answers2