我刚刚修复了它.我从RootViewController中复制了代码，完全删除了.h和.m文件，创建了新文件，并将名称更改为RootViewController并将代码粘贴回了.然后进行编译.

I just fixed it. I copied the code out of RootViewController, deleted the .h and .m files entirely, created new files and changed the name to RootViewController and pasted the code back in. It then compiled.