IOS Dynamic Add Attribute method

Write in front:

The dynamic addition of properties is not a wanton increase, it is required to write code. If a class does not have that property, it will be error-free at compile-time, resulting in a failure. The reason is also called dynamic add is generally because you can not rewrite a class, and the corresponding property to add it! Don't pull that much. Cut to the chase:

You first need to create a category to write to the appropriate Set/get method.

#import <UIKit/UIKit.h>@interface  UILabel (Associate)-(void) Setflashcolor: (Uicolor *) Flashcolor; -(Uicolor *) Getflashcolor; @end

uilabel+associate.h

The focus has come to realize:

#import "uilabel+associate.h"#import<objc/runtime.h>@implementationUILabel (Associate)Static CharFlashcolorkey;- (void) Setflashcolor: (Uicolor *) flashcolor{objc_setassociatedobject (self,&Flashcolorkey, Flashcolor, objc_association_retain_nonatomic);}-(Uicolor *) getflashcolor{returnObjc_getassociatedobject (Self, &flashcolorkey);}@end

UILABEL+ASSOCIATE.M

Call:

UILabel *lab = [[UILabel alloc] init];    [Lab Setflashcolor:[uicolor Redcolor];    NSLog (@ "%@", [Lab Getflashcolor]);

View Code

Thus: the addition of attributes using runtime is actually through "Objc_export void Objc_setassociatedobject (ID object, const void *key, id value, OBJC_ Associationpolicy policy) "to add the.

A pure C method, passing in an OC object, setting a value according to a key, this is the whole method.

Thinking:

。。。 Always feel that the implementation of the C function inside there is a large container ... (only for individuals who want to: ）

Note: code from http://www.cnblogs.com/luoguoqiang1985/p/3551966.html

　　　　

IOS Dynamic Add Attribute method