【发布时间】：2022-06-17 17:18:50
【问题描述】：
我将 Flutter 更新到了最新版本，并且在更新后我收到了以下错误：
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/persistent_bottom_nav_bar-4.0.2/lib/persistent-tab-view.widget.dart:368:22: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/widgets/binding.dart').
WidgetsBinding.instance!.addPostFrameCallback((_) {
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/persistent_bottom_nav_bar-4.0.2/lib/animations/animations.dart:55:20: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/widgets/binding.dart').
WidgetsBinding.instance!.addPostFrameCallback((_) {
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/persistent_bottom_nav_bar-4.0.2/lib/nav-bar-styles/style-6-bottom-nav-bar.widget.dart:44:20: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/widgets/binding.dart').
WidgetsBinding.instance!.addPostFrameCallback((_) {
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/persistent_bottom_nav_bar-4.0.2/lib/nav-bar-styles/style-8-bottom-nav-bar.widget.dart:44:20: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/widgets/binding.dart').
WidgetsBinding.instance!.addPostFrameCallback((_) {
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/persistent_bottom_nav_bar-4.0.2/lib/nav-bar-styles/style-11-bottom-nav-bar.widget.dart:46:20: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/widgets/binding.dart').
WidgetsBinding.instance!.addPostFrameCallback((_) {
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/persistent_bottom_nav_bar-4.0.2/lib/nav-bar-styles/style-12-bottom-nav-bar.widget.dart:46:20: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/widgets/binding.dart').
WidgetsBinding.instance!.addPostFrameCallback((_) {
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/persistent_bottom_nav_bar-4.0.2/lib/nav-bar-styles/style-13-bottom-nav-bar.widget.dart:46:20: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/widgets/binding.dart').
WidgetsBinding.instance!.addPostFrameCallback((_) {
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/persistent_bottom_nav_bar-4.0.2/lib/nav-bar-styles/style-14-bottom-nav-bar.widget.dart:46:20: Warning: Operand of null-aware operation '!' has type 'WidgetsBinding' which excludes null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/widgets/binding.dart').
WidgetsBinding.instance!.addPostFrameCallback((_) {
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/getwidget-2.0.5/lib/components/sticky_header/gf_sticky_header_builder.dart:63:28: Warning: Operand of null-aware operation '?.' has type 'WidgetsBinding' which excludes null.
- 'WidgetsBinding' is from 'package:flutter/src/widgets/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/widgets/binding.dart').
WidgetsBinding.instance?.endOfFrame.then((_) {
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flare_flutter-3.0.2/lib/flare_render_box.dart:167:26: Warning: Operand of null-aware operation '?.' has type 'SchedulerBinding' which excludes null.
- 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/scheduler/binding.dart').
SchedulerBinding.instance?.cancelFrameCallbackWithId(_frameCallbackID);
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flare_flutter-3.0.2/lib/flare_render_box.dart:170:28: Warning: Operand of null-aware operation '?.' has type 'SchedulerBinding' which excludes null.
- 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/scheduler/binding.dart').
SchedulerBinding.instance?.scheduleFrameCallback(_beginFrame) ?? -1;
^
/C:/src/flutter/.pub-cache/hosted/pub.dartlang.org/flare_flutter-3.0.2/lib/flare_render_box.dart:272:26: Warning: Operand of null-aware operation '?.' has type 'SchedulerBinding' which excludes null.
- 'SchedulerBinding' is from 'package:flutter/src/scheduler/binding.dart' ('/C:/src/flutter/packages/flutter/lib/src/scheduler/binding.dart').
SchedulerBinding.instance?.cancelFrameCallbackWithId(_frameCallbackID);
^
flutter doctor:
[√] Flutter (Channel dev, 2.13.0-0.3.pre, on Microsoft Windows [Version 10.0.19043.1645], locale tr-TR)
[√] Android toolchain - develop for Android devices (Android SDK version 32.0.0)
[√] Chrome - develop for the web
[√] Visual Studio - develop for Windows (Visual Studio Community 2019 16.11.13)
[√] Android Studio (version 2021.1)
[√] VS Code (version 1.66.2)
[√] Connected device (4 available)
[√] HTTP Host Availability
• No issues found!
我用flutter upgrade升级了Flutter。升级后我开始收到这些错误。我搜索了很多，但找不到解决方案。问题是什么？我该如何解决？提前感谢您的帮助。
【问题讨论】：
-
只需删除空检查（！和？）
标签： flutter