Method 'addObserver' cannot be called on 'WidgetsBinding?' because it is potentially null.

[abhihasabe]

/C:/flutter/.pub-cache/hosted/pub.dartlang.org/velocity_x-3.5.1/lib/src/flutter/common/velocity_ensure_visible.dart:67:29: Error: Method 'addObserver' cannot be called on 'WidgetsBinding?' because it is potentially null.

• 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/flutter/packages/flutter/lib/src/widgets/binding.dart').
  Try calling using ?. instead.
  WidgetsBinding.instance.addObserver(this);
  ^^^^^^^^^^^
  /C:/flutter/.pub-cache/hosted/pub.dartlang.org/velocity_x-3.5.1/lib/src/flutter/common/velocity_ensure_visible.dart:72:29: Error: Method 'removeObserver' cannot be called on 'WidgetsBinding?' because it is potentially null.
• 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/flutter/packages/flutter/lib/src/widgets/binding.dart').
  Try calling using ?. instead.
  WidgetsBinding.instance.removeObserver(this);
  ^^^^^^^^^^^^^^
  /C:/flutter/.pub-cache/hosted/pub.dartlang.org/velocity_x-3.5.1/lib/src/flutter/drawer.dart:150:29: Error: Method 'addPostFrameCallback' cannot be called on 'WidgetsBinding?' because it is potentially null.
• 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/flutter/packages/flutter/lib/src/widgets/binding.dart').
  Try calling using ?. instead.
  WidgetsBinding.instance.addPostFrameCallback(getBoxHeight);
  ^^^^^^^^^^^^^^^^^^^^
  /C:/flutter/.pub-cache/hosted/pub.dartlang.org/velocity_x-3.5.1/lib/src/flutter/marquee.dart:51:29: Error: Method 'addPostFrameCallback' cannot be called on 'WidgetsBinding?' because it is potentially null.
• 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/flutter/packages/flutter/lib/src/widgets/binding.dart').
  Try calling using ?. instead.
  WidgetsBinding.instance.addPostFrameCallback((callback) {
  ^^^^^^^^^^^^^^^^^^^^
  /C:/flutter/.pub-cache/hosted/pub.dartlang.org/velocity_x-3.5.1/lib/src/flutter/popup_menu.dart:186:29: Error: Method 'addPostFrameCallback' cannot be called on 'WidgetsBinding?' because it is potentially null.
• 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/flutter/packages/flutter/lib/src/widgets/binding.dart').
  Try calling using ?. instead.
  WidgetsBinding.instance.addPostFrameCallback((call) {
  ^^^^^^^^^^^^^^^^^^^^

FAILURE: Build failed with an exception.

• Where:
  Script 'C:\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 1102

• What went wrong:
  Execution failed for task ':app:compileFlutterBuildDebug'.

Process 'command 'C:\flutter\bin\flutter.bat'' finished with non-zero exit value 1

• Try:
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

• Get more help at https://help.gradle.org

BUILD FAILED in 30s
Exception: Gradle task assembleDebug failed with exit code 1

[adomiciliooapp]

Hi, I have the same bug, any news?

[iampawan]

Which flutter version you are using @adomiciliooapp, @abhihasabe ?

[elkana]

this is known issue when using flutter before 3.
downgrade to version 3.4.0 for temporary solution

[iampawan]

Fixed in 3.6.0