OC for iOS development (for the previous Supplement 1)-@class, circular reference

(a) The usefulness of @class

[Email protected] Function: Just tell the compiler, a name is a class (#import "Person.h" is to include all the method declaration, each time to copy, not conducive to improve performance)

@class person; just tell the compiler that person is a class (to implement a method that also contains the person header file in the. m file)

2. Specification of a class referenced in development

1> declaring Classes in. h files with @class

2> with #import来包含类的所有东西in. m Files

(ii) Circular reference solution at both ends

First Class

1> End With retain

2> End With assign

Type II

1> End With strong

2> End With weak

OC for iOS development (for the previous Supplement 1)[email protected], circular reference