java.lang.SecurityException: Permission Denial: null asks to run as user 9 but is calling from use

突然报这个错

  java.lang.SecurityException: Permission Denial: null asks to run as user 9 but is calling from user 0; this requires android.permission.INTERACT_ACROSS_USERS_FULL or android.permission.INTERACT_ACROSS_USERS

看着像是缺少权限，于是乎加了

<permission android:name="android.permission.INTERACT_ACROSS_USERS_FULL" android:protectionLevel="signature"/>

然并卵

查了下

他解决这个问题的方式是：将BaseAcivity里的getUserId改为了getApplicationUserId。方法名有关系？

然后我查看了下我代码，我发现我也有个userId,难道是因为不能以userId来定义变量名和者方法名，我抱着试试的态度，将userId改为了userID.不报错了。。。。。amazing

为什么项目里不能出现useId呢？？？？？？？？怎么不安全呢？？？不明白