objc_setAssociatedObject与Block的简单使用

本文主要是介绍objc_setAssociatedObject与Block的简单使用，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

• UIAlertView的扩展

.h文件

#import <UIKit/UIKit.h>
typedef void (^successBlock)(NSInteger buttonIndex);@interface UIAlertView (Block)<UIAlertViewDelegate>- (void)showWithBlock:(successBlock)block;@end

.m文件

#import "UIAlertView+Block.h"
#import <objc/runtime.h>static const char alertKey;@implementation UIAlertView (Block)- (void)showWithBlock:(successBlock)block
{if (block){objc_setAssociatedObject(self, &alertKey, block, OBJC_ASSOCIATION_RETAIN_NONATOMIC);self.delegate = self;}[self show];
}- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{successBlock block = objc_getAssociatedObject(self, &alertKey);block(buttonIndex);
}@end

• UIButton的扩展

.h文件

#import <UIKit/UIKit.h>typedef void (^btnBlock)();@interface UIButton (Block)- (void)handelWithBlock:(btnBlock)block;@end

.m文件

#import "UIButton+Block.h"
#import <objc/runtime.h>static const char btnKey;@implementation UIButton (Block)- (void)handelWithBlock:(btnBlock)block
{if (block){objc_setAssociatedObject(self, &btnKey, block, OBJC_ASSOCIATION_RETAIN_NONATOMIC);}[self addTarget:self action:@selector(btnAction) forControlEvents:UIControlEventTouchUpInside];
}- (void)btnAction
{btnBlock block = objc_getAssociatedObject(self, &btnKey);block();
}@end

tips: 使用objc_setAssociatedObject，需要引入头文件 #import <objc/runtime.h>

---

void objc_setAssociatedObject(id object, const void key, id value, objc_AssociationPolicy policy);id objc_getAssociatedObject(id object, const void key);

这两个方法可以让一个对象和另一个对象关联，就是说一个对象可以保持对另一个对象的引用，并获取那个对象。有了这些，就能实现属性功能了。 policy可以设置为以下这些值：

enum {OBJC_ASSOCIATION_ASSIGN = 0,
OBJC_ASSOCIATION_RETAIN_NONATOMIC = 1,
OBJC_ASSOCIATION_COPY_NONATOMIC = 3,
OBJC_ASSOCIATION_RETAIN = 01
OBJC_ASSOCIATION_COPY = 01403
};

 

这篇关于objc_setAssociatedObject与Block的简单使用的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！

---