strong修饰符实现weak效果（对象释放时，属性置nil）

 

 

////  NSObject+EZ_Dealloc.h//  EZToolKit////  Created by yangjun zhu on 2017/1/6.//  Copyright © 2017年 Cactus. All rights reserved.//#import <Foundation/Foundation.h>typedef void (^voidBlock)(void);@interface EZBlockExecutor : NSObject- (id)initWithBlock:(voidBlock)block;@end@interface NSObject (EZ_Dealloc)- (void)ez_runAtDealloc:(voidBlock)block;@end

 

////  NSObject+EZ_Dealloc.m//  EZToolKit////  Created by yangjun zhu on 2017/1/6.//  Copyright © 2017年 Cactus. All rights reserved.//#import "NSObject+EZ_Dealloc.h"#import <objc/runtime.h>@interface EZBlockExecutor() {    voidBlock _block;}@end@implementation EZBlockExecutor- (id)initWithBlock:(voidBlock)aBlock{    self = [super init];        if (self) {        _block = [aBlock copy];    }        return self;}- (void)dealloc{    _block ? _block() : nil;}@endconst void *runAtDeallocBlockKey = &runAtDeallocBlockKey;@implementation NSObject (EZ_Dealloc)- (void)ez_runAtDealloc:(voidBlock)block{    if (block) {        EZBlockExecutor *executor = [[EZBlockExecutor alloc] initWithBlock:block];                objc_setAssociatedObject(self,                                 runAtDeallocBlockKey,                                 executor,                                 OBJC_ASSOCIATION_RETAIN);    }}@end

 https://github.com/easyui/EZToolKit/blob/master/EZToolKit/EZCategory/Foundation/NSObject/NSObject%2BEZ_Dealloc.m