NSObject比较实用的Category

最新推荐文章于 2018-09-26 14:14:42 发布

原创最新推荐文章于 2018-09-26 14:14:42 发布 · 1.5k 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#iOS #Objective C #Runtime

iOS 专栏收录该内容

249 篇文章

订阅专栏

本文详细探讨了Objective-C与Swift两种语言在iOS开发领域的应用与区别，包括其语法特点、性能表现及实际项目案例分析。

头文件

//
//  NSObject+Utils.h
//  UIView+CategoriesDemo
//
//  Created by su xinde on 13-4-12.
//  Copyright (c) 2013年 su xinde. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface NSObject (Utils)

//perform block1 in main thread,when finished perform block2 in background
+ (void)perform:(void(^)())block1 withCompletionHandler:(void (^)())block2;
- (void)perform:(void(^)())block1 withCompletionHandler:(void (^)())block2;


//use Object to deliver param(retain)
- (void)setObject:(id)obj;
- (id)getObject;



//默认block回调 key:DefaultEventHandler
- (void)handlerDefaultEventWithBlock:(id)block;
- (id)blockForDefaultEvent;

//设置一个block作为回调
- (void)handlerEventWithBlock:(id)block withIdentifier:(NSString *)identifier;
- (id)blockForEventWithIdentifier:(NSString *)identifier;

//send object
//handle block with default identifier is @"ObjectSingleObjectDictionary".
- (void)receiveObject:(void(^)(id object))sendObject;
- (void)sendObject:(id)object;

//tag can't be nil
- (void)receiveObject:(void(^)(id object))sendObject withIdentifier:(NSString *)identifier;
- (void)sendObject:(id)object withIdentifier:(NSString *)identifier;



//给UITableViewCell的数据存储计算过的行高的，防止重复计算
//用法： 在ViewController的heightForRowAtIndexPath:方法里返回cell高度height之前
//      先调用一次［self setCellRowHeight:height]; 然后在cellForRowAtIndexPath:
//      方法里调用[self cellRowHeight];即可获取行高，免去直接调用heightForRowAtIndexPath:造成的重复计算。
- (float)cellRowHeight;
- (void)setCellRowHeight:(float)height;
@end

实现文件

#import "NSObject+Utils.h"
#import <objc/runtime.h>

@implementation NSObject (Utils)

+ (void)perform:(void(^)())block1 withCompletionHandler:(void (^)())block2
{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        block1();
        dispatch_async(dispatch_get_main_queue(),^{
            block2();
        });
    });
}
- (void)perform:(void(^)())block1 withCompletionHandler:(void (^)())block2
{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        block1();
        dispatch_async(dispatch_get_main_queue(),^{
            block2();
        });
    });
}
//======================

const char ObjectStoreKey;

- (void)setObject:(id)obj
{
    objc_setAssociatedObject(self, &ObjectStoreKey, obj, OBJC_ASSOCIATION_RETAIN);
}
- (id)getObject
{
    return objc_getAssociatedObject(self, &ObjectStoreKey);
}
//=======================

const char ObjectEventHandlerDictionary;


- (void)handlerDefaultEventWithBlock:(id)block
{
    [self handlerEventWithBlock:block withIdentifier:@"DefaultEventHandler"];
}


- (id)blockForDefaultEvent
{
    return [self blockForEventWithIdentifier:@"DefaultEventHandler"];
}

- (void)handlerEventWithBlock:(id)block withIdentifier:(NSString *)identifier
{
    NSAssert(identifier != nil, @"identifier can't be nil.");
    NSMutableDictionary *eventHandlerDictionary = objc_getAssociatedObject(self,&ObjectEventHandlerDictionary);
    if(eventHandlerDictionary == nil)
    {
        eventHandlerDictionary = [[NSMutableDictionary alloc] init];
        objc_setAssociatedObject(self, &ObjectEventHandlerDictionary, eventHandlerDictionary, OBJC_ASSOCIATION_RETAIN);
    }
    
    [eventHandlerDictionary setObject:block forKey:identifier];
}

- (id)blockForEventWithIdentifier:(NSString *)identifier
{
    NSAssert(identifier != nil, @"identifier can't be nil.");
    NSDictionary *eventHandlerDictionary = objc_getAssociatedObject(self,&ObjectEventHandlerDictionary);
    if(eventHandlerDictionary == nil) return nil;
    return [eventHandlerDictionary objectForKey:identifier];
}

//=======================
const char ObjectSingleObjectDictionary;

- (void)receiveObject:(void(^)(id object))sendObject
{
    [self receiveObject:sendObject withIdentifier:@"ObjectSingleObjectDictionary"];
}
- (void)sendObject:(id)object
{
    [self sendObject:object withIdentifier:@"ObjectSingleObjectDictionary"];
}

- (void)receiveObject:(void(^)(id object))sendObject withIdentifier:(NSString *)identifier
{
    NSAssert(identifier != nil, @"identifier can't be nil.");
    NSMutableDictionary *eventHandlerDictionary = objc_getAssociatedObject(self,&ObjectSingleObjectDictionary);
    if(eventHandlerDictionary == nil)
    {
        eventHandlerDictionary = [[NSMutableDictionary alloc] init];
        objc_setAssociatedObject(self, &ObjectSingleObjectDictionary, eventHandlerDictionary, OBJC_ASSOCIATION_RETAIN);
    }
    
    [eventHandlerDictionary setObject:sendObject forKey:identifier];
}

- (void)sendObject:(id)object withIdentifier:(NSString *)identifier
{
    NSAssert(identifier != nil, @"identifier can't be nil.");
    
    NSDictionary *eventHandlerDictionary = objc_getAssociatedObject(self,&ObjectSingleObjectDictionary);
    if(eventHandlerDictionary == nil)
        return;
    
    void(^block)(id object) =  [eventHandlerDictionary objectForKey:identifier];
    block(object);
}

//=========================

const char CellRowHeightKey;
- (float)cellRowHeight
{
    NSNumber *number = objc_getAssociatedObject(self,&CellRowHeightKey);
    if(number == nil) return -1;
    return [number floatValue];
}
- (void)setCellRowHeight:(float)height
{
    objc_setAssociatedObject(self,
                             &CellRowHeightKey,
                             [NSNumber numberWithFloat:height],
                             OBJC_ASSOCIATION_RETAIN);
}

@end

参考：https://github.com/zhangxigithub/BlockUI

https://github.com/pandamonia/BlocksKit