具体用法一:

- (void)viewDidLoad {
    [super viewDidLoad];
    
    NSString *firsrString = @"我是第一个按钮";  // �传入的对象可以是字符串,字典,数组类型
    NSString *secondString = @"我是第二个按钮";
    UIButton *btn = [[UIButton alloc] initWithFrame:CGRectMake(100, 100, 150, 50)];
    [btn setBackgroundColor:[UIColor redColor]];
    [btn setTitle:@"按钮传值" forState:UIControlStateNormal];
    [self.view addSubview:btn];
    
    objc_setAssociatedObject(btn, "firstObject", firsrString, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    objc_setAssociatedObject(btn, "secondObject", secondString, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    [btn addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];
}

- (void)click:(UIButton *)sender{
    id first = objc_getAssociatedObject(sender, "firstObject");
    id second = objc_getAssociatedObject(sender, "secondObject");
    NSLog(@"%@--%@", first, second);
}

解释一下:

• 第一步: 设定关联objc_setAssociatedObject(btn, "firstObject", someObject, OBJC_ASSOCIATION_RETAIN_NONATOMIC);第一个参数：btn为被关联者(主体)，第二个参数：firstObject为指向关联的对象的指针(一般为一个static字符串)，第三个参数：关联的对象实例，第四个对象：关联的方式(有几种，类似设定.h文件属性时候的 assign,retain等)

• 第二步：得到关联的对象
  id first = objc_getAssociatedObject(btn, "firstObject");第一个参数：为被关联者第二个参数：为关联对象的指针。

具体用法二:

tableview 点击 cell上的编辑按钮传值:

image.png

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    StudioTemplateCell *cell = [tableView dequeueReusableCellWithIdentifier:@"StudioTemplateCellID"];
    [cell.editButton addTarget:self action:@selector(editClick:) forControlEvents:UIControlEventTouchUpInside];
     objc_setAssociatedObject(cell.editButton, @"indexPathKey", indexPath, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    return cell;
}
- (void)editClick:(UIButton *)btn{
    NSIndexPath *index = objc_getAssociatedObject(btn, @"indexPathKey");
    NSLog(@"%@", index);
}