给分类（Category）添加自定义属性

最新推荐文章于 2025-02-20 23:07:05 发布

原创最新推荐文章于 2025-02-20 23:07:05 发布 · 1.6k 阅读

0 ·

CC 4.0 BY-SA版权

备份同时被 2 个专栏收录

38 篇文章

订阅专栏

转载

10 篇文章

订阅专栏

本文介绍了一个使用Objective-C关联对象实现UIView扩展的例子，通过这种方式可以在UIView中存储并访问自定义对象，同时避免了内存管理的问题。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

@interface MyInfo : NSObject
@property(nonatomic,assign) int num;
@property(nonatomic,retain) NSString* text;
@end

@interface UIView(MyView)
@property(nonatomic,retain) MyInfo* info;
@end

@implementation MyInfo
-(id)init
{
    self = [super init];
    self.text = @"";
    self.num = 0;
    return self;
}

- (id)copyWithZone:(nullable NSZone *)zone
{
    MyInfo* info = [[[self class] allocWithZone: zone] init];
    info.num = self.num;
    info.text = [self.text copyWithZone:zone];
    return info;
}
@end

@implementation UIView(MyView)
static void *infoKey = &infoKey;
-(void)setInfo:(MyInfo *)info
{
    objc_setAssociatedObject(self, &infoKey, info, OBJC_ASSOCIATION_COPY);
}

-(MyInfo*)info
{
    return objc_getAssociatedObject(self, &infoKey);
}

@end

testcode

 MyInfo* info = [[MyInfo alloc] init];
    UIView* view1 = [[UIView alloc] init];
    info.num = 1;
    info.text = @"view1";
    view1.info = info;

    info = [[MyInfo alloc] init];
    UIView* view2 = [[UIView alloc] init];
    info.num = 2;
    info.text = @"view2";
    view2.info = info;

    NSLog(@"%d %@, %d %@",view1.info.num,view1.info.text,view2.info.num,view2.info.text);