封装NSMapTable并简易的使用

NSMapTable是弱引用的字典,可以用来存储对象,该对象消失了也没有关系,对于控制器越级跳转相当有用:)

WeakDictionary.h 与 WeakDictionary.m

////  WeakDictionary.h//  弱引用字典////  http://www.cnblogs.com/YouXianMing///  Copyright (c) 2014年 Y.X. All rights reserved.//#import 
     
      #define GET_WEAK_OBJECT(key)                 [WeakDictionary objectForKey:(key)]#define REGISTER_WEAK_OBJECT(object, key)    [WeakDictionary addObject:(object) forKey:(key)]@interface WeakDictionary : NSObject+ (void)addObject:(id)object forKey:(NSString *)key;+ (id)objectForKey:(NSString *)key;@end
     

////  WeakDictionary.m//  弱引用字典////  http://www.cnblogs.com/YouXianMing///  Copyright (c) 2014年 Y.X. All rights reserved.//#import "WeakDictionary.h"static NSMapTable  *weakDictionary = nil;@implementation WeakDictionary+ (void)initialize{    if (self == [WeakDictionary class])    {        // 强引用key值弱引用object        weakDictionary = [NSMapTable strongToWeakObjectsMapTable];    }}+ (void)addObject:(id)object forKey:(NSString *)key{    if (object == nil || key == nil)    {        NSLog(@"object or key should not be nil.");        return;    }        if ([weakDictionary objectForKey:key] == nil)    {        [weakDictionary setObject:object forKey:key];    }}+ (id)objectForKey:(NSString *)key{    return [weakDictionary objectForKey:key];}@end

提供的两个category

NSObject+WeakDictionary.h 与 NSObject+WeakDictionary.m

////  NSObject+WeakDictionary.h//  YouXianMing////  Created by YouXianMing on 14-9-20.//  Copyright (c) 2014年 YouXianMing. All rights reserved.//#import 
     
      @interface NSObject (WeakDictionary)- (void)storeToWeakDictionaryWithKey:(NSString *)key;@end
     

////  NSObject+WeakDictionary.m//  YouXianMing////  Created by YouXianMing on 14-9-20.//  Copyright (c) 2014年 YouXianMing. All rights reserved.//#import "NSObject+WeakDictionary.h"#import "WeakDictionary.h"@implementation NSObject (WeakDictionary)- (void)storeToWeakDictionaryWithKey:(NSString *)key{    [WeakDictionary addObject:self forKey:key];}@end

NSString+WeakDictionary.h 与 NSString+WeakDictionary.m

////  NSString+WeakDictionary.h//  YouXianMing////  Created by YouXianMing on 14-9-20.//  Copyright (c) 2014年 YouXianMing. All rights reserved.//#import 
     
      @interface NSString (WeakDictionary)- (id)recoverFromWeakDictionary;@end
     

////  NSString+WeakDictionary.m//  YouXianMing////  Created by YouXianMing on 14-9-20.//  Copyright (c) 2014年 YouXianMing. All rights reserved.//#import "NSString+WeakDictionary.h"#import "WeakDictionary.h"@implementation NSString (WeakDictionary)- (id)recoverFromWeakDictionary{    return [WeakDictionary objectForKey:self];}@end

使用示例的话,以上一篇教程为例子来演示: