在layout文件夹下建立子文件后()，子文件夹里xml文件出现Layout:cannot find the declaration of element 'LinearLayout'
解决方案：需要在build.gradle里增加sourceSets节点将添加布局引用
注意子文件夹命名layout-XXX格式，其他格式可能依然报错
参考https://blog.csdn.net/qq_39897005/article/details/80415910
如上操作后，可能还有这个错误
If a resource is only defined in folders with qualifiers like -land or -en, and there is no default declaration in the base folder (layout or values etc), then the app will crash if that resource is accessed on a device where the device is in a configuration missing the given qualifier.
暂时没找到解决方案