How OC category injects new properties

Using OC Runtime

In. h

@interface NSObject (Laserunicorn) @property (nonatomic, strong) Laserunicorn *laserunicorn; @end

In. m

#import <objc/runtime.h>static void * Laserunicornpropertykey = &LaserUnicornPropertyKey; @implementation NSObject (Laserunicorn)-(Laserunicorn *) Laserunicorn {    return objc_getassociatedobject (self, Laserunicornpropertykey);} -(void) Setlaserunicorn: (Laserunicorn *) Unicorn {    objc_setassociatedobject (self, Laserunicornpropertykey, Unicorn, objc_association_retain_nonatomic); } @end

A more concise way to try @selector (Nameofgetter)

-(Laserunicorn *) Laserunicorn {    return objc_getassociatedobject (self, @selector (Laserunicorn));} -(void) Setlaserunicorn: (Laserunicorn *) Unicorn {    objc_setassociatedobject (self, @selector (Laserunicorn), Unicorn, objc_association_retain_nonatomic); }

　　

How OC category injects new properties