2번째인생

The following _TypeError was thrown building PrimaryScrollController(_NestedScrollController#82ad6(inner, no clients)): Null check operator used on a null value   class PostDataListMenu extends StatefulWidget { final PostData? postdata ; PostDataListMenu({Key? key , this . postdata }) : super (key: key) ; @override _PostDataListMenu createState () => _PostDataListMenu (postdata!) ; } 수정 후 -- null check 수정 class _PostDataListNotice extends State<PostDataListNotice> { final PostData? postdata; final ScrollController _scrollController = ScrollController () ; _PostDataListNotice( this . postdata ) ; @override void initState () { super .initState() ; } _PostDataListMenu createState () => _PostDataListMenu (postdata) ;

 type 'Null' is not a subtype of type 'Widget' in type cast Flutter를 다운그레이드하지 마세요. 문제: ! 이 오류는 초기화되지 않은 nullable 인스턴스에  bang 연산자( )를 사용할 때 발생합니다 . 예를 들어: String? string; // Nullable String void main() { var len = string!.length; // Runtime error: Null check operator used on a null value } 솔루션: 로그를 열면 오류가 발생한 프로젝트의 파일을 가리키는 줄이 있어야 합니다. null 값에 사용되는 null 검사 연산자 #0 메인 (package:example/main.dart:22:16) 거기에 있으면 다음 방법 중 하나를 사용하여 문제를 해결할 수 있습니다. 지역 변수 사용 var s = string; if (s != null ) { var len = s.length; // Safe } 사용  ?. 및 ?? var len = string?.length ?? 0 ; // Provide a default value if string was null. 스택 추적은 프로젝트에 속하지 않는 파일을 가리킬 수도 있습니다.  예를 들어: 1. 이용  Navigator 하시거나 MediaQuery 이 오류는 에 비동기적으로 액세스하려고 할 때도 발생합니다  BuildContext . mounted 따라서 에 접근하기 전에  위젯이 있는지 먼저 확인해야 합니다  BuildContext . Future< void > foo() async { // Some async operation await compute(); // Check `mounted` before accessing 'context'. if (mounted...

 Launching lib\main.dart on sdk gphone x86 in debug mode... Running Gradle task 'assembleDebug'... FAILURE: Build failed with an exception. * Where: Build file 'C:\Users\mycom1\AppData\Local\Pub\Cache\hosted\pub.dev\package_info_plus-4.0.2\android\build.gradle' line: 28 * What went wrong: A problem occurred evaluating project ':package_info_plus'. > No signature of method: build_39cvu39wudi60k4qhyc66csdm.android() is applicable for argument types: (build_39cvu39wudi60k4qhyc66csdm$_run_closure2) values: [build_39cvu39wudi60k4qhyc66csdm$_run_closure2@67198049] * 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 25s Exception: Gradle task assembleDebug failed with exit code 1 buildscript { ext.kotlin_version = '1.8.0' repositories { google() jcenter() ...

  kotlin_version 확인 gradle 버젼 확인 buildscript { ext.kotlin_version = '1.8.0' repositories { google() jcenter() } dependencies { classpath 'com.android.tools.build:gradle:7.4.2' classpath "org.jetbrains.kotlin:kotlin-gradle-plugin: $kotlin_version " classpath 'com.google.gms:google-services:4.3.8' } } allprojects { repositories { google() jcenter() } } rootProject.buildDir = '../build' subprojects { project.buildDir = " $ { rootProject.buildDir } / $ { project.name } " } subprojects { project.evaluationDependsOn( ':app' ) } tasks.register( "clean" , Delete) { delete rootProject.buildDir }

  [!] Android toolchain - develop for Android devices (Android SDK version 30.0.1)     • Android SDK at C:/Users/mycom1/AppData/Local/Android/Sdk     • Platform android-31, build-tools 30.0.1     • ANDROID_HOME = C:/Users/mycom1/AppData/Local/Android/Sdk     • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java     • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)     X Android license status unknown.       Run `flutter doctor --android-licenses` to accept the SDK licenses.       See https://flutter.dev/docs/get-started/install/windows#android-setup for more details.