Error Note - Android Studio

Android license status unknown.

Happened on attempting to install Flutter on windows
on
flutter doctor
got notice

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.

on
flutter doctor --android-licenses
got error

Exception in thread "main" java.lang.NoClassDefFoundError: javax/xml/bind/annotation/XmlSchema
        at com.android.repository.api.SchemaModule$SchemaModuleVersion.<init>(SchemaModule.java:156)
        at com.android.repository.api.SchemaModule.<init>(SchemaModule.java:75)
        at com.android.sdklib.repository.AndroidSdkHandler.<clinit>(AndroidSdkHandler.java:81)
        at com.android.sdklib.tool.sdkmanager.SdkManagerCli.main(SdkManagerCli.java:73)
        at com.android.sdklib.tool.sdkmanager.SdkManagerCli.main(SdkManagerCli.java:48)
Caused by: java.lang.ClassNotFoundException: javax.xml.bind.annotation.XmlSchema
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
        ... 5 more

Solution

Install Android SDK Command-line Tools (latest)
Files->Setting->Appearance & Behavior -> System Settings -> Android SDK -> SDK Tools -> Install Android SDK Command-line Tools (latest)

after intall,

flutter doctor --android-licenses
accept all the licenses then problem solved.

---

Loading Devices

There will be additional device panel for after install the Flutter plugin, and the original one will show "loading devices"

Unable to locate adb

Solution

reintall Android SDK Platform-Tools
Files->Setting->Appearance & Behavior -> System Settings -> Android SDK -> SDK Tools -> Android SDK Platform-Tools

ANDROID_SDK_ROOT not set

Solution

set environment variable ANDROID_SDK_ROOT to the location of Android SDK, like:
C:\Users\UserName\AppData\Local\Android\Sdk

Tips

use AVD manager to stop the emulated device

---

Cannot resolve symbol 'GradleException'

running gradle task 'assembledebug'

is downloading resorces

Solution

wait it out. It resolved the next morning

Could not open cp_init remapped class cache

Could not initialize class org.codehaus.groovy.classgen.Verifier

happened after clean gradle cache

Solution

switch back to main.dart

Flutter Inspector: installing devtools

Try File > Invalid Caches / Restart

not work

Solution

wait it out, reboot

Activating Dart DevTools

When

runing main.dart on real device while it is already running on an emulated device

Plant(Black/White) Screen

When

run on real device

Solution

if Profile "main.dart" works fine, just need to wait

Failed to start monitoring

Waiting for another flutter command to release the startup lock

Solution

remove ./flutter/bin/cache/lockfile

---

Running "flutter pub get" in flutter_app takes forever

Solution

check if the version of your required package is in correct format
check pubspec.yaml for possible error (even there is no highlight)