简化通知中心的使用

说明

1. 简化通知中心，笔者曾经实现过不需要移除的通知中心，基于弱引用集合（相对于强引用集合如NSArray，NSDictionary等）编写，本例子并无太多新意

2. 简化的通知中心由一个对象组织控制，不需要你手动移除被监听的对象，这是唯一的一点点有新意的地方

3. 在处理接收通知对象的地方，笔者提供了一个方法来简化取值操作，相对应的，发送通知消息的时候，被发送的对象也请使用指定的格式（都是用weak修饰，无需担心被持有）

源码

https://github.com/YouXianMing/NotificationCenter

//
//  NotificationCenterObject.h
//  NotificationCenter
//
//  Created by YouXianMing on 15/7/15.
//  Copyright (c) 2015年 YouXianMing. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface PostObject : NSObject

@property (nonatomic, strong) NSString *flag;
@property (nonatomic, weak)   id        data;

/**
 *  便利构造器初始化对象
 *
 *  @param flag 识别标签
 *  @param data 数据
 *
 *  @return 实例对象
 */
+ (instancetype)postObjectWithFlag:(NSString *)flag data:(id)data;

/**
 *  处理通知中心事件
 *
 *  @param sender 通知中心的通知对象
 *
 *  @return 实例对象
 */
+ (instancetype)accessNotificationCenterObject:(id)sender;

@end

///////////////////////////////////////////////////////////////////////////////////////////

@interface NotificationCenterObject : NSObject

/**
 *  === 必须先使用此方法进行初始化 ===
 *
 *  初始化通知中心
 *
 *  @param observer 观察对象
 *  @param name     注册标签
 *  @param selector 执行用selector
 *
 *  @return 实例对象
 */
+ (instancetype)withObserver:(id)observer
                registerName:(NSString *)name
                    selector:(SEL)selector;

/**
 *  给指定注册标签发信息
 *
 *  @param name     注册标签
 *  @param postData 发送的对象
 */
+ (void)postToRegisterName:(NSString *)name data:(PostObject *)postData;

@property (nonatomic, readonly, strong) NSString *name;
@property (nonatomic, readonly, weak)   id        observer;

/**
 *  移除
 */
- (void)remove;

/**
 *  重新添加上
 */
- (void)reAdd;

@end

///////////////////////////////////////////////////////////////////////////////////////////

/**
 *  创建通知对象
 *
 *  @param flag 标签
 *  @param data 传递的数据
 *
 *  @return 通知对象
 */
static inline PostObject * POST_OBJECT(NSString *flag, id data) {

    return [PostObject postObjectWithFlag:flag data:data];
}

/**
 *  处理通知的对象
 *
 *  @param sender 接收的通知对象
 *
 *  @return 通知对象
 */
static inline PostObject * ACCESS_POST_OBJECT(id sender) {

    return [PostObject accessNotificationCenterObject:sender];
}

/**
 *  发送通知消息
 *
 *  @param name       指定的标签
 *  @param postObject 通知的对象
 *
 */
static inline void POST_MSG_TO(NSString *name, PostObject *postObject) {

    [NotificationCenterObject postToRegisterName:name data:postObject];
}

/**
 *  注册通知中心
 *
 *  @param name     指定的标签
 *  @param observer 被注册的对象
 *  @param selector 执行的句柄
 *
 *  @return 实例对象
 */
static inline NotificationCenterObject * REGISTER_MSG_CENTER_WITH(NSString *name, id observer, SEL selector) {

    return [NotificationCenterObject withObserver:observer registerName:name selector:selector];
}

//
//  NotificationCenterObject.m
//  NotificationCenter
//
//  Created by YouXianMing on 15/7/15.
//  Copyright (c) 2015年 YouXianMing. All rights reserved.
//

#import "NotificationCenterObject.h"

@implementation PostObject

+ (instancetype)postObjectWithFlag:(NSString *)flag data:(id)data {

    PostObject *postObject = [PostObject new];
    postObject.flag        = flag;
    postObject.data        = data;

    return postObject;
}

+ (instancetype)accessNotificationCenterObject:(id)sender {

    PostObject *postData = nil;

    if ([sender isKindOfClass:[NSNotification class]]) {

        NSNotification *notiData = sender;

        if ([notiData.object isKindOfClass:[PostObject class]]) {

            postData = notiData.object;
        }
    }

    return postData;
}

@end

@interface NotificationCenterObject ()

@property (nonatomic, strong) NSString *name;
@property (nonatomic, weak)   id        observer;
@property (nonatomic)         SEL       observerSelector;

@property (nonatomic)         BOOL      haveAddObserver;

@end

@implementation NotificationCenterObject

+ (void)postToRegisterName:(NSString *)name data:(PostObject *)postData {

    [[NSNotificationCenter defaultCenter] postNotificationName:name object:postData];
}

+ (instancetype)withObserver:(id)observer registerName:(NSString *)name selector:(SEL)selector {

    NotificationCenterObject *notificationCenterObject = [NotificationCenterObject new];
    notificationCenterObject.name                      = name;
    notificationCenterObject.observer                  = observer;
    notificationCenterObject.observerSelector          = selector;

    notificationCenterObject.haveAddObserver           = YES;
    [[NSNotificationCenter defaultCenter] addObserver:observer selector:selector name:name object:nil];

    return notificationCenterObject;
}

- (void)remove {

    if (self.haveAddObserver == YES && _name && _observer) {
        self.haveAddObserver = NO;
        [[NSNotificationCenter defaultCenter] removeObserver:_observer name:_name object:nil];
    }
}

- (void)reAdd {

    if (self.haveAddObserver == NO && _name && _observer) {
        self.haveAddObserver = YES;
        [[NSNotificationCenter defaultCenter] addObserver:_observer selector:_observerSelector name:_name object:nil];
    }
}

- (void)dealloc {

    if (self.haveAddObserver == YES) {

        NSLog(@"已经释放");
        [[NSNotificationCenter defaultCenter] removeObserver:_observer name:_name object:nil];
    }
}

@end

细节

用内联函数将OC风格函数简化为C风格函数，能够稍微缩短代码编写长度，其实并无实用价值，装的成分居多。