”这个操作符允许你在编译时避免对可能为null的变量进行空检查,但增加了运行时错误的风险。 2. 阐述在何种情况下会出现“dart null check operator used on a null value”这个错误 当使用空检查操作符(!)的变量实际上为null时,Dart运行时将抛出一个异常,错误消息为“dart null check operator used on a null...
后果是，你的程序将抛出NullPointerException异常，系统将被挂起，不再提供正常服务。 当然，...
但肯定是从这两个屏幕中选出的。使用getx包时，需要在GetMaterialApp()中添加main.dart ...
身份验证Service.dart文件: import 'package:firebase_auth/firebase_auth.dart'; import 'package:google_sign_in/google_sign_in.dart'; class AuthService { signInWithGoogle() async { // begin interactive sign in process final GoogleSignInAccount? gUser = await GoogleSignIn().signIn(); // obtain...
During my development of https://dart-review.googlesource.com/c/sdk/+/400660, I ran into a subtle bug where the following null check (in the class NonParameterVariableElementImpl) was failing: @override Element get enclosingElement3 => s...
_TypeError: Null check operator used on a null value File "framework.dart", line 5606, in StatefulElement.state File "framework.dart", line 4831, in Element.findAncestorStateOfType File "scaffold.dart", line 62, in _WcScaffoldState.didChangeDependencies ...
Flutter：“Null check operator used on a null value”(在空值上使用空检查运算符)，不带Null check...
throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.") } def flutterVersionCode = localProperties.getProperty('flutter.versionCode') if (flutterVersionCode == null) { flutterVersionCode = '1' } def flutterVersionName = localProperties.get...
--null 没有说明 --num-raster-threads 用于栅格化内容的辅助线程数。 --oauth-account-manager-url 没有说明 --oauth2-client-id 没有说明 --oauth2-client-secret 没有说明 --oculus 以下是WebXr支持的运行时。 --offer-in-settings 没有说明 --on-the-fly-mhtml-hash-computation 计算正在保存的MHTML文...
TypeError media_kit_video_player.dart in MediaKitVideoPlayer.buildView at line 178 within video_player_media_kit @override Widget buildView(int textureId) { return Video( key: ValueKey(_videoControllers[textureId]!), controller: _videoCo...