flutter-0

安装Flutter环境时出现Android license status unknown错误，主要原因是Java9之后版本删掉了一些库，本文讲详细描述如何解决报错问题

遇到问题

安装Flutter环境，最后执行flutter doctor时出现：

Android license status unknown.

按照网上方法

flutter doctor --android-licenses

AndroidSDK\tools\bin\sdkmanager.bat --update

还是出现错误：

Exception in thread "main" java.lang.NoClassDefFoundError: javax/xml/bind/annotation/XmlSchema
        at com.android.repository.api.SchemaModule$SchemaModuleVersion.<init>(Sch.......

解决办法

下载缺失库

https://repo1.maven.org/maven2/javax/activation/activation/1.1.1/activation-1.1.1.jar
https://repo1.maven.org/maven2/com/sun/xml/bind/jaxb-impl/2.3.3/jaxb-impl-2.3.3.jar
https://repo1.maven.org/maven2/org/glassfish/jaxb/jaxb-xjc/2.3.3/jaxb-xjc-2.3.3.jar
https://repo1.maven.org/maven2/org/glassfish/jaxb/jaxb-jxc/2.3.3/jaxb-jxc-2.3.3.jar
https://repo1.maven.org/maven2/javax/xml/bind/jaxb-api/2.3.1/jaxb-api-2.3.1.jar
https://repo1.maven.org/maven2/com/sun/istack/istack-commons-runtime/3.0.7/istack-commons-runtime-3.0.7.jar
https://repo1.maven.org/maven2/org/glassfish/jaxb/jaxb-core/2.3.0.1/jaxb-core-2.3.0.1.jar

重命名，去掉版本号，放在如下目录下

AndroidSDK\tools\jaxb

修改sdkmanager.bat

文本编辑工具打开sdkmanager.bat文件进行编辑，打开后，在大约66行那里我们会看到这样的一行代码：

set CLASSPATH=%APP_HOME%\jaxb\activation.jar;%APP_HOME%\jaxb\jaxb-impl.jar;%APP_HOME%\jaxb\jaxb-xjc.jar;%APP_HOME%\jaxb\jaxb-core.jar;%APP_HOME%\jaxb\jaxb-jxc.jar;%APP_HOME%\jaxb\jaxb-api.jar;%APP_HOME%\jaxb\istack-commons-runtime.jar;%APP_HOME%\lib\dvlib-26.0.0-dev.jar;%APP_HOME%\lib\jimfs-1.1.jar;%APP_HOME%\lib\jsr305-1.3.9.jar;%APP_HOME%\lib\repository-26.0.0-dev.jar;%APP_HOME%\lib\j2objc-annotations-1.1.jar;%APP_HOME%\lib\layoutlib-api-26.0.0-dev.jar;%APP_HOME%\lib\gson-2.3.jar;%APP_HOME%\lib\httpcore-4.2.5.jar;%APP_HOME%\lib\commons-logging-1.1.1.jar;%APP_HOME%\lib\commons-compress-1.12.jar;%APP_HOME%\lib\annotations-26.0.0-dev.jar;%APP_HOME%\lib\error_prone_annotations-2.0.18.jar;%APP_HOME%\lib\animal-sniffer-annotations-1.14.jar;%APP_HOME%\lib\httpclient-4.2.6.jar;%APP_HOME%\lib\commons-codec-1.6.jar;%APP_HOME%\lib\common-26.0.0-dev.jar;%APP_HOME%\lib\kxml2-2.3.0.jar;%APP_HOME%\lib\httpmime-4.1.jar;%APP_HOME%\lib\annotations-12.0.jar;%APP_HOME%\lib\sdklib-26.0.0-dev.jar;%APP_HOME%\lib\guava-22.0.jar

再次运行

sdkmanager.bat --update

flutter doctor --android-licenses

flutter doctor

正常，不再报错