Beginner runtime--Realization of the article (category add attribute)

in iOS development, category does not add attributes by default, but the runtime is easy to handle.

1. Add classification NSObject (Extension) to NSObject,

1> added in Nsobject+extension.h

@property (nonatomic, copy) NSString *value;

2> in the nsobject+extension.m.

#import "Nsobject+extension.h"

#import <objc/runtime.h>

@implementation NSObject (Extension)

static char Valuekey; Key of the associated property value

-(void) SetValue: (NSString *) value

{

Associate a value with an object

To store a value in an object

Objc_setassociatedobject (self, &valuekey, value, objc_association_copy_nonatomic);

}

-(NSString *) value

{

Use Valuekey to take value values

Return Objc_getassociatedobject (self, &valuekey);

}

@end

2. Testing in Viewcontroller

-(void) Viewdidload {

[Super Viewdidload];

NSString *str = @ "Jack";

Str.value = @ "abc";

Self.value = @ "hahaha";

NSLog (@ "%@", Str.name, Self.name);

}

Operation Result:

2015-06-10 17:07:27.488 run-time applications - Category Add Property [1698:63864] ABC hahaha #import <objc/runtime.h>

Beginner runtime--Realization of the article (category add attribute)