IOS @class #import

Randy Marsh：

When I develop, I have only three things in mind that never cause me any problems.

1. Import super classes
2. Import parent classes (when you have children and parents)
3. Import classes outside your project (like in frameworks and libraries)

For all other classes (subclasses and child classes in my project self), I declare them via forward-class.

 

Justin：

Simple answer: You #import or #include when there is a physical dependency. Otherwise, you use forward declarations (@class MONClass ,struct MONStruct , @protocol MONProtocol ).

Here are some common examples of physical dependence:

• Any C or C++ value (a pointer or reference is not a physical dependency). If you have aCGPoint as an ivar or property, the compiler will need to see the declaration ofCGPoint .
• Your superclass.
• A method you use.