常用宏定义 #define

#define BACK(block) dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), block)
#define MAIN(block) dispatch_async(dispatch_get_main_queue(),block)


//Device
#define isRetina ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(640, 960), [[UIScreen mainScreen] currentMode].size) : NO)

谢谢16楼提出的 “ 判断Retina设备建议使用[[UIScreen mainScreen] scale]==2，不然横屏下那个宏定义判断的有问题 ”




#define iPhone5 ([UIScreen instancesRespondToSelector:@selector(currentMode)] ? CGSizeEqualToSize(CGSizeMake(640, 1136), [[UIScreen mainScreen] currentMode].size) : NO)

#define isPad (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)

//区分模拟器和真机

#if TARGET_OS_IPHONE
//iPhone Device
#endif

#if TARGET_IPHONE_SIMULATOR
//iPhone Simulator
#endif


//ARC
#if __has_feature(objc_arc)
    //compiling with ARC
#else
    // compiling without ARC

#endif

#define USER_DEFAULT [NSUserDefaults standardUserDefaults]

#define DATA_ENV [DataEnvironment sharedDataEnvironment]

#define ImageNamed(_pointer) [UIImage imageNamed:[UIUtil imageName:_pointer]]



#pragma mark - common functions

#define RELEASE_SAFELY(__POINTER) { [__POINTER release]; __POINTER = nil; }



#pragma mark - degrees/radian functions

#define degreesToRadian(x) (M_PI * (x) / 180.0)

#define radianToDegrees(radian) (radian*180.0)/(M_PI)


#pragma mark - color functions

#define RGBCOLOR(r,g,b) [UIColor colorWithRed:(r)/255.0f green:(g)/255.0f blue:(b)/255.0f alpha:1]

#define RGBACOLOR(r,g,b,a) [UIColor colorWithRed:(r)/255.0f green:(g)/255.0f blue:(b)/255.0f alpha:(a)]
#define ITTDEBUG
#define ITTLOGLEVEL_INFO     10
#define ITTLOGLEVEL_WARNING  3
#define ITTLOGLEVEL_ERROR    1

#ifndef ITTMAXLOGLEVEL

#ifdef DEBUG
    #define ITTMAXLOGLEVEL ITTLOGLEVEL_INFO
#else
    #define ITTMAXLOGLEVEL ITTLOGLEVEL_ERROR
#endif

#endif

// The general purpose logger. This ignores logging levels.
#ifdef ITTDEBUG
  #define ITTDPRINT(xx, ...)  NSLog(@"%s(%d): " xx, __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__)
#else
  #define ITTDPRINT(xx, ...)  ((void)0)
#endif

// Prints the current method's name.
#define ITTDPRINTMETHODNAME() ITTDPRINT(@"%s", __PRETTY_FUNCTION__)

// Log-level based logging macros.
#if ITTLOGLEVEL_ERROR <= ITTMAXLOGLEVEL
  #define ITTDERROR(xx, ...)  ITTDPRINT(xx, ##__VA_ARGS__)
#else
  #define ITTDERROR(xx, ...)  ((void)0)
#endif

#if ITTLOGLEVEL_WARNING <= ITTMAXLOGLEVEL
  #define ITTDWARNING(xx, ...)  ITTDPRINT(xx, ##__VA_ARGS__)
#else
  #define ITTDWARNING(xx, ...)  ((void)0)
#endif

#if ITTLOGLEVEL_INFO <= ITTMAXLOGLEVEL
  #define ITTDINFO(xx, ...)  ITTDPRINT(xx, ##__VA_ARGS__)
#else
  #define ITTDINFO(xx, ...)  ((void)0)
#endif

#ifdef ITTDEBUG
  #define ITTDCONDITIONLOG(condition, xx, ...) { if ((condition)) { \
                                                  ITTDPRINT(xx, ##__VA_ARGS__); \
                                                } \
                                              } ((void)0)
#else
  #define ITTDCONDITIONLOG(condition, xx, ...) ((void)0)
#endif


#define ITTAssert(condition, ...)                                       \
do {                                                                      \
    if (!(condition)) {                                                     \
        [[NSAssertionHandler currentHandler]                                  \
            handleFailureInFunction:[NSString stringWithUTF8String:__PRETTY_FUNCTION__] \
                                file:[NSString stringWithUTF8String:__FILE__]  \
                            lineNumber:__LINE__                                  \
                            description:__VA_ARGS__];                             \
    }                                                                       \
} while(0)

7.单例

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// @interface #define singleton_interface(className) \ + (className *)shared##className;     // @implementation #define singleton_implementation(className) \ static className *_instance; \ + (id)allocWithZone:(struct _NSZone *)zone \ { \      static dispatch_once_t onceToken; \      dispatch_once(&onceToken, ^{ \          _instance = [ super allocWithZone:zone]; \      }); \      return _instance; \ } \ + (className *)shared##className \ { \      static dispatch_once_t onceToken; \      dispatch_once(&onceToken, ^{ \          _instance = [[self alloc] init]; \      }); \      return _instance; \ }