ios - Flutter @Error:此库已禁用空安全功能
问题描述
我正在构建一个 Flutter 应用程序,当我为 Android 构建应用程序时,该应用程序运行良好,但当我开始为 iOS 构建应用程序时,我开始面临“此库禁用空安全功能”的错误
错误如下:
Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:100:4: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Uri? _currentUriBase;
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:106:7: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? _current;
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:120:16: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
[String? part2,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:121:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part3,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:122:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part4,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:123:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part5,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:124:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part6,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:125:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part7]) =>
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:258:16: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
[String? part2,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:259:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part3,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:260:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part4,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:261:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part5,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:262:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part6,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:263:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part7,
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:264:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String? part8]) =>
^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety/lib/path.dart:358:37: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
String relative(String path, {String? from}) =>
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:126:9: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Object? invoke(covariant T intent);
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:235:8: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Key? key,
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:330:50: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Object invoke(covariant T intent, [BuildContext? context]);
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:334:52: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
typedef OnInvokeCallback<T extends Intent> = Object? Function(T intent);
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:361:9: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Object? invoke(covariant T intent) => onInvoke(intent);
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:386:9: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Object? invokeAction(covariant Action<Intent> action, covariant Intent intent, [BuildContext? context]) {
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:386:95: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Object? invokeAction(covariant Action<Intent> action, covariant Intent intent, [BuildContext? context]) {
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:420:8: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Key? key,
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:436:25: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final ActionDispatcher? dispatcher;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:495:22: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
static VoidCallback? handler<T extends Intent>(BuildContext context, T intent, {bool nullOk = false}) {
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:510:19: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
static Action<T>? find<T extends Intent>(BuildContext context, {bool nullOk = false}) {
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:595:16: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
static Object? invoke<T extends Intent>(
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:653:22: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Set<Action<Intent>>? listenedActions = <Action<Intent>>{};
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:718:8: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Key? key,
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:719:21: Error: Expected '}' before this.
required Widget child,
^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:724:25: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final ActionDispatcher? dispatcher;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:887:8: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Key? key,
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:914:18: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final FocusNode? focusNode;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:920:34: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final Map<Type, Action<Intent>>? actions;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:923:35: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final Map<LogicalKeySet, Intent>? shortcuts;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:929:27: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final ValueChanged<bool>? onShowFocusHighlight;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:934:27: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final ValueChanged<bool>? onShowHoverHighlight;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:939:27: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final ValueChanged<bool>? onFocusChange;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:1031:41: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
void _mayTriggerCallback({VoidCallback? task, FocusableActionDetector? oldWidget}) {
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/actions.dart:1031:72: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
void _mayTriggerCallback({VoidCallback? task, FocusableActionDetector? oldWidget}) {
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:121:8: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Key? key,
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:164:17: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final Duration? reverseDuration;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:250:22: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
AnimationController? _controller;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:251:8: Error: A method declaration needs an explicit list of parameters.
Try adding a parameter list to the method declaration.
late Animation<double> _firstAnimation;
^^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:251:26: Error: Expected '{' before this.
late Animation<double> _firstAnimation;
^^^^^^^^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:251:26: Error: Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
Try adding the name of the type of the variable or the keyword 'var'.
late Animation<double> _firstAnimation;
^^^^^^^^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:252:8: Error: A method declaration needs an explicit list of parameters.
Try adding a parameter list to the method declaration.
late Animation<double> _secondAnimation;
^^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:252:26: Error: Expected '{' before this.
late Animation<double> _secondAnimation;
^^^^^^^^^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:252:8: Error: 'Animation' is already declared in this scope.
late Animation<double> _secondAnimation;
^^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:251:8: Context: Previous declaration of 'Animation'.
late Animation<double> _firstAnimation;
^^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:252:26: Error: Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
Try adding the name of the type of the variable or the keyword 'var'.
late Animation<double> _secondAnimation;
^^^^^^^^^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:274:3: Error: 'Animation' isn't a type.
Animation<double> _initAnimation(Curve curve, bool inverted) {
^^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_cross_fade.dart:274:3: Context: This isn't a type.
Animation<double> _initAnimation(Curve curve, bool inverted) {
^^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:33:28: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final AnimationController? controller;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:34:39: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final AnimatedListRemovedItemBuilder? removedItemBuilder;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:272:8: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Key? key,
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:340:25: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final ScrollController? controller;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:350:13: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final bool? primary;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:358:22: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final ScrollPhysics? physics;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:377:27: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final EdgeInsetsGeometry? padding;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:388:27: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
static AnimatedListState? of(BuildContext context, { bool nullOk = false }) {
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:737:8: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Key? key,
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:774:33: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
static SliverAnimatedListState? of(BuildContext context, {bool nullOk = false}) {
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:837:14: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
_ActiveItem? _removeActiveItemAt(List<_ActiveItem> items, int itemIndex) {
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_list.dart:842:14: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
_ActiveItem? _activeItemAt(List<_ActiveItem> items, int itemIndex) {
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_size.dart:57:8: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Key? key,
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_size.dart:58:11: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Widget? child,
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_size.dart:101:17: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final Duration? reverseDuration;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_switcher.dart:64:63: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
typedef AnimatedSwitcherLayoutBuilder = Widget Function(Widget? currentChild, List<Widget> previousChildren);
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_switcher.dart:149:8: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
Key? key,
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_switcher.dart:175:15: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
final Widget? child;
^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/animated_switcher.dart:192:17: Error: Null safety features are disabled for this library.
Try removing the package language version or setting the language version to 2.10 or higher.
该错误还表明 required 不是类型
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:400:5: Error: 'required' isn't a type.
required this.filter,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:820:5: Error: 'required' isn't a type.
required ShapeBorder shape,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:907:5: Error: 'required' isn't a type.
required this.color,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:999:5: Error: 'required' isn't a type.
required this.clipper,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1002:5: Error: 'required' isn't a type.
required this.color,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1114:5: Error: 'required' isn't a type.
required this.transform,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1151:5: Error: 'required' isn't a type.
required double angle,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1180:5: Error: 'required' isn't a type.
required Offset offset,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1219:5: Error: 'required' isn't a type.
required double scale,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1301:5: Error: 'required' isn't a type.
required this.link,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1361:5: Error: 'required' isn't a type.
required this.link,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1507:5: Error: 'required' isn't a type.
required this.translation,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1569:5: Error: 'required' isn't a type.
required this.quarterTurns,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1644:5: Error: 'required' isn't a type.
required this.padding,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1921:5: Error: 'required' isn't a type.
required this.delegate,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1951:5: Error: 'required' isn't a type.
required this.id,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
/Users/himanshu/flutter/packages/flutter/lib/src/widgets/basic.dart:1952:5: Error: 'required' isn't a type.
required Widget child,
^^^^^^^^
/Users/himanshu/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.2/lib/meta.dart:224:16: Context: This isn't a type.
const Required required = Required();
^^^^^^^^
颤振医生 -v 如下:
[√] Flutter (Channel stable, 1.20.3, on Microsoft Windows [Version 10.0.19041.508], locale en-US)
• Flutter version 1.20.3 at C:\src\flutter
• Framework revision 216dee60c0 (3 weeks ago), 2020-09-01 12:24:47 -0700
• Engine revision d1bc06f032
• Dart version 2.9.2
[√] Android toolchain - develop for Android devices (Android SDK version 30.0.0-rc2)
• Android SDK at C:\Users\Ashu\AppData\Local\Android\Sdk
• Platform android-29, build-tools 30.0.0-rc2
• Java binary at: C:\Program Files\Android\Android Studio1\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b04)
• All Android licenses accepted.
[!] Android Studio (version 3.2)
• Android Studio at C:\Program Files\Android\Android Studio
• Flutter plugin version 31.3.1
• Dart plugin version 181.5656
X Unable to determine bundled Java version.
• Try updating or re-installing Android Studio.
[√] Android Studio (version 3.6)
• Android Studio at C:\Program Files\Android\Android Studio1
• Flutter plugin version 31.3.1
• Dart plugin version 181.5656
• Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b04)
[√] VS Code (version 1.49.0)
• VS Code at C:\Users\Ashu\AppData\Local\Programs\Microsoft VS Code
• Flutter extension version 3.14.1
[!] Connected device
! No devices available
谢谢你。
解决方案
我通过执行以下操作解决了它(对于 Windows 10 上的 Visual Code):
在命令提示符下(或在 PATH 中使用颤振的任何终端):
flutter upgrade
并确保版本至少为 2.12(这是在不将其用作实验功能的情况下启用空安全性所需的最低版本(我相信))
PS C:\> flutter upgrade
Flutter is already up to date on channel stable
Flutter 2.0.2 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 8962f6dc68 (2 days ago) • 2021-03-11 13:22:20 -0800
Engine • revision 5d8bf811b3
Tools • Dart 2.12.1
确认后,我检查了项目中我当前的 sdk-version 是什么(在我的情况下是以下内容sdk: ">=2.7.0 <3.0.0"
:)
所以我将其更新为以下内容:sdk: ">=2.12.0 <3.0.0"
.
所以环境应该如下所示:
environment:
sdk: ">=2.12.0 <3.0.0"
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