iOS判断设备类型常用宏定义

#define IS_IPAD (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)  
#define IS_IPHONE (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)  
#define IS_RETINA ([[UIScreen mainScreen] scale] >= 2.0)  
  
#define SCREEN_WIDTH ([[UIScreen mainScreen] bounds].size.width)  
#define SCREEN_HEIGHT ([[UIScreen mainScreen] bounds].size.height)  
#define SCREEN_MAX_LENGTH (MAX(SCREEN_WIDTH, SCREEN_HEIGHT))  
#define SCREEN_MIN_LENGTH (MIN(SCREEN_WIDTH, SCREEN_HEIGHT))  
  
#define IS_IPHONE_4_OR_LESS (IS_IPHONE && SCREEN_MAX_LENGTH < 568.0)  
#define IS_IPHONE_5 (IS_IPHONE && SCREEN_MAX_LENGTH == 568.0)  
#define IS_IPHONE_6 (IS_IPHONE && SCREEN_MAX_LENGTH == 667.0)  
#define IS_IPHONE_6P (IS_IPHONE && SCREEN_MAX_LENGTH == 736.0)