# association

**Repository Path**: yahibo/association

## Basic Information

- **Project Name**: association
- **Description**: 关联对象 objc_setAssociatedObject runtime
- **Primary Language**: Objective-C
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2018-06-28
- **Last Updated**: 2020-12-19

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# ios_association

#### 项目介绍
关联对象 objc_setAssociatedObject runtime

#### 方法介绍



```
objc_setAssociatedObject(id _Nonnull object, const void * _Nonnull key,
id _Nullable value, objc_AssociationPolicy policy)
object     关联对象
key        关联对象的关键字 必须是唯一不可变的常量
value      被关联者要关联到object上
policy     关联策略
```



```
1、给对象关联一个属性
objc_setAssociatedObject(array, &array_key, dic, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

2、通过绑定key获取关联对象
NSDictionary *di = objc_getAssociatedObject(array, &array_key);

3、移除关联对象
objc_setAssociatedObject(array, &array_key, nil, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

4、移除所有关联对象
objc_removeAssociatedObjects(array);
```
#### 示例

 **创建一个UIButton的分类 给button动态添加一个属性，一个block点击回调方法** 


```
UIButton+Property.h 申明
#import <UIKit/UIKit.h>

typedef void(^ButtonEventBlock)(UIButton *response);
@interface UIButton (Property)
@property (nonatomic,strong) NSString *ids;
@property (nonatomic,strong) ButtonEventBlock clickBlock;

@end
```

```
UIButton+Property.m 实现
#import "UIButton+Property.h"
#import <objc/runtime.h>

const NSString *button_property_ids = @"button_property_ids";
const NSString *button_property_click_event = @"button_property_click_event";
@implementation UIButton (Property)
-(instancetype)init{
    self = [super init];
    if (self) {
       NSLog(@"初始化");
    }
    return self;
}
-(instancetype)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        NSLog(@"初始化");
        [self addTarget:self action:@selector(clickBtnEvent:) forControlEvents:UIControlEventTouchUpInside];
    }
    return self;
}
-(void)setIds:(NSString *)ids{
    objc_setAssociatedObject(self, &button_property_ids, ids, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
-(NSString *)ids{
    return objc_getAssociatedObject(self, &button_property_ids);
}
-(void)setClickBlock:(ButtonEventBlock)clickBlock{
    objc_setAssociatedObject(self, &button_property_click_event, clickBlock, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
-(ButtonEventBlock)clickBlock{
    return objc_getAssociatedObject(self, &button_property_click_event);
}
//击事件中调用方法把点击事件通过代码块传递出去
-(void)clickBtnEvent:(UIButton *)button{
    ButtonEventBlock block = [self clickBlock];
    if (block) {
        block(button);
    }
}

@end


```


```
引入分类调创建分类对象测试属性及回调方法
//关联一个方法，点击事件代码块回调
UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake((self.view.frame.size.width-100)/2, 200, 100, 40)];
button.backgroundColor = [UIColor redColor];
button.ids = @"hibo";
[button setTitle:@"点击" forState:UIControlStateNormal];
[self.view addSubview:button];
button.clickBlock = ^(UIButton *response) {
    NSLog(@"代码块实现点击事件回调：%@",response.titleLabel.text);
};
```








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