使用extract（$ variables）获取内容，但变量未定义

I haven't gotten the hang of the extract() function, and transferring variables. I have a method in a user controller where some variables are defined, and sent in an array to a view function in a parent controller, where the array is extracted. Then the view is required. But the variables turn out undefined. The array contents can be printed though. I haven't gotten the hang of the extract() func