设计根据标示符全局只运行一次的类

//
//  StaticFlag.h
//  Static
//
//  Copyright (c) 2014年 Y.X. All rights reserved.
//

#import <Foundation/Foundation.h>

typedef void (^StaticFlagBlock)();

@interface StaticFlag : NSObject

+ (void)flag:(NSString *)flag
       class:(Class)objectClass
   firstTime:(StaticFlagBlock)firstTime
  otherTimes:(StaticFlagBlock)otherTimes;

@end

//
//  StaticFlag.m
//  Static
//
//  Copyright (c) 2014年 Y.X. All rights reserved.
//

#import "StaticFlag.h"

static NSMutableDictionary *flagDictionary  = nil;

@implementation StaticFlag

+ (void)initialize
{
    if (self == [StaticFlag class])
    {
        flagDictionary = [NSMutableDictionary new];
    }
}

+ (void)flag:(NSString *)flag
       class:(Class)objectClass
   firstTime:(StaticFlagBlock)firstTime
  otherTimes:(StaticFlagBlock)otherTimes
{
    NSString *str = [NSStringFromClass(objectClass) stringByAppendingString:flag];
    NSLog(@"%@", str);
    
    if ([flagDictionary valueForKey:str] == nil)
    {
        [flagDictionary setObject:@"HAVE" forKey:str];
        firstTime();
    }
    else
    {
        otherTimes();
    }
}

@end

//
//  AppDelegate.m
//  OnlyOne
//
//  Copyright (c) 2014年 Y.X. All rights reserved.
//

#import "AppDelegate.h"
#import "StaticFlag.h"

#define FLAG  @"YouXianMing"

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    [StaticFlag flag:FLAG
               class:[AppDelegate class]
           firstTime:^{
               NSLog(@"第一次");
           }
          otherTimes:^{
              NSLog(@"第二次");
          }];
    
    
    [StaticFlag flag:FLAG
               class:[AppDelegate class]
           firstTime:^{
               NSLog(@"第一次");
           }
          otherTimes:^{
              NSLog(@"第二次");
          }];
    
    
    return YES;
}

@end