Category添加weak属性的精简版本

来源：互联网发布：淘宝微能量运动旗舰店编辑：程序博客网时间：2024/06/05 03:45

网上有很多版本，我提供一种不用加新类就可以实现的方法。

创建NSObject的Category

NSObject+Ext.h

#import <Foundation/Foundation.h>typedef void (^DeallocBlock)();@interface NSObject (Ext)@property (nonatomic, weak) id weakObj;@property (nonatomic, copy) DeallocBlock block;@end

NSObject+Ext.m

#import "NSObject+Ext.h"#import <objc/runtime.h>static NSString *WEAK_KEY = @"weakObj";static NSString *BLOCK_KEY = @"block";@implementation NSObject (Ext)- (id)weakObj {    return objc_getAssociatedObject(self, &WEAK_KEY);}- (void)setWeakObj:(id)weakObj {    [weakObj setBlock:^() {        objc_setAssociatedObject(self, &WEAK_KEY, nil, OBJC_ASSOCIATION_ASSIGN);    }];    objc_setAssociatedObject(self, &WEAK_KEY, weakObj, OBJC_ASSOCIATION_ASSIGN);}- (DeallocBlock)block {    return objc_getAssociatedObject(self, &BLOCK_KEY);}- (void)setBlock:(DeallocBlock)block {    objc_setAssociatedObject(self, &BLOCK_KEY, block, OBJC_ASSOCIATION_COPY_NONATOMIC);}#pragma clang diagnostic push#pragma clang diagnostic ignored "-Wobjc-protocol-method-implementation"- (void)dealloc {    self.block ? self.block() : nil;    objc_setAssociatedObject(self, &BLOCK_KEY, nil, OBJC_ASSOCIATION_ASSIGN);}#pragma clang diagnostic pop@end

测试用法

NSObject *obj1 = [NSObject new];NSObject *obj2 = [NSObject new];obj1.weakObj = obj2;NSLog(@"%@", obj1.weakObj);obj2 = nil;NSLog(@"%@", obj1.weakObj);

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