私有API是SDK中未记录的API。例如，框架类可能声明一个不打算由外部开发人员使用的方法。不保证私有API的行为。您甚至无法确定该方法将在未来的平台更新中存在。它的声明可能在公开分发的SDK头文件中不可用。如果您坚持使用SDK文档中公开定义的内容，那么您就可以了。

A private API is an API that is not documented in the SDK. For instance, a framework class might declare a method that is not intended to be used by outside developers. The behavior of a private API is not guaranteed. You can't even be sure that the method will be there in the future updates of the platform. Its declaration is probably not available in publicly distributed SDK header files. If you stick to things publicly defined in the SDK documentation, you'll be OK.