获取文件名的后缀
let str = (NSStringFromClass(GPMainCollectionViewCell.self) as NSString).pathExtension
(lldb) po (NSStringFromClass(GPMainCollectionViewCell.self) as NSString).pathExtension
"GPMainCollectionViewCell"
直接获取得到的是:项目+类名
(lldb) po NSStringFromClass(GPMainCollectionViewCell.self)
"momodaJigsaw.GPMainCollectionViewCell"