Flutter Error: Method 'addPostFrameCallback' cannot be called on 'SchedulerBinding?&#-CodePudding

Whenever I try to run my Flutter app I get this error, it was running and I don't know why now it's not. I've even reset to previous commit and it still won't run.

../../../development/flutter/.pub-cache/hosted/pub.dartlang.org/get-4.6.3/lib/get_navigation/src/extension_navigation.dart:357:33: Error: Method 'addPostFrameCallback' cannot be called on 'SchedulerBinding?' because it is potentially null.
 - 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('../../../development/flutter/packages/flutter/lib/src/scheduler/binding.dart').
Try calling using ?. instead.
      SchedulerBinding.instance.addPostFrameCallback((_) {
                                ^^^^^^^^^^^^^^^^^^^^
../../../development/flutter/.pub-cache/hosted/pub.dartlang.org/get-4.6.3/lib/get_navigation/src/extension_navigation.dart:468:33: Error: Method 'addPostFrameCallback' cannot be called on 'SchedulerBinding?' because it is potentially null.
 - 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('../../../development/flutter/packages/flutter/lib/src/scheduler/binding.dart').
Try calling using ?. instead.
      SchedulerBinding.instance.addPostFrameCallback((_) {
                                ^^^^^^^^^^^^^^^^^^^^
../../../development/flutter/.pub-cache/hosted/pub.dartlang.org/get-4.6.3/lib/get_navigation/src/snackbar/snackbar.dart:452:31: Error: Method 'addPostFrameCallback' cannot be called on 'SchedulerBinding?' because it is potentially null.
 - 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('../../../development/flutter/packages/flutter/lib/src/scheduler/binding.dart').
Try calling using ?. instead.
    SchedulerBinding.instance.addPostFrameCallback(
                              ^^^^^^^^^^^^^^^^^^^^
../../../development/flutter/.pub-cache/hosted/pub.dartlang.org/get-4.6.3/lib/get_state_manager/src/rx_flutter/rx_notifier.dart:130:31: Error: Method 'addPostFrameCallback' cannot be called on 'SchedulerBinding?' because it is potentially null.
 - 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('../../../development/flutter/packages/flutter/lib/src/scheduler/binding.dart').
Try calling using ?. instead.
    SchedulerBinding.instance.addPostFrameCallback((_) => onReady());
                              ^^^^^^^^^^^^^^^^^^^^
../../../development/flutter/.pub-cache/hosted/pub.dartlang.org/get-4.6.3/lib/get_state_manager/src/simple/get_controllers.dart:90:29: Error: Method 'addObserver' cannot be called on 'WidgetsBinding?' because it is potentially null.
 - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../development/flutter/packages/flutter/lib/src/widgets/binding.dart').
Try calling using ?. instead.
    WidgetsBinding.instance.addObserver(this);
                            ^^^^^^^^^^^
../../../development/flutter/.pub-cache/hosted/pub.dartlang.org/get-4.6.3/lib/get_state_manager/src/simple/get_controllers.dart:96:29: Error: Method 'removeObserver' cannot be called on 'WidgetsBinding?' because it is potentially null.
 - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../development/flutter/packages/flutter/lib/src/widgets/binding.dart').
Try calling using ?. instead.
    WidgetsBinding.instance.removeObserver(this);
                            ^^^^^^^^^^^^^^
../../../development/flutter/.pub-cache/hosted/pub.dartlang.org/get-4.6.3/lib/get_navigation/src/router_report.dart:53:31: Error: Method 'addPostFrameCallback' cannot be called on 'WidgetsBinding?' because it is potentially null.
 - 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('../../../development/flutter/packages/flutter/lib/src/widgets/binding.dart').
Try calling using ?. instead.
      WidgetsBinding.instance.addPostFrameCallback((_) {
                              ^^^^^^^^^^^^^^^^^^^^

FAILURE: Build failed with an exception.

* Where:
Script '/home/ibrahimdev/development/flutter/packages/flutter_tools/gradle/flutter.gradle' line: 1102

* What went wrong:
Execution failed for task ':app:compileFlutterBuildDebug'.
> Process 'command '/home/ibrahimdev/development/flutter/bin/flutter'' 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 18s

CodePudding user response：

Nullability for SchedulerBinding, WidgetsBinding and other clases changed in Flutter 3.0.0. So several packages update their code to remove warning.

If during your development you did not update any package you may wonder why you are getting the error.

Make sure that you are running flutter get and not flutter upgrade.

To fix the problem:

Run flutter clean
Delete pubspeck.lock if exists
Run flutter get

If you still see the error. Maybe the package still updating when you run flutter get.

So you can remove the ^ for example: flutterfire_ui: ^0.4.0 5 will become flutterfire_ui: 0.4.0 5

CodePudding user response：

ran into the same problem and solved it by updating my flutter version to version 3.0. Run flutter upgrade in your console and reopen vscode(or your editor). check the bottom right (on vscode) to ensure it has been updated to version 3.0.0

CodePudding user response：

i get the same problem.And you need to upgrade flutter 3.0.0 version.