使用宏定义判断设备型号
//判断是否为iPhone或ipad
#define UI_IS_IPAD ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad)
#define UI_IS_IPHONE ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone)
//判断iPhone型号
#define UI_IS_IPHONE4 (UI_IS_IPHONE && [[UIScreen mainScreen] bounds].size.height < 568.0)
#define UI_IS_IPHONE5 (UI_IS_IPHONE && [[UIScreen mainScreen] bounds].size.height == 568.0)
#define UI_IS_IPHONE6 (UI_IS_IPHONE && [[UIScreen mainScreen] bounds].size.height == 667.0)
#define UI_IS_IPHONE6PLUS (UI_IS_IPHONE && [[UIScreen mainScreen] bounds].size.height == 736.0 || [[UIScreen mainScreen] bounds].size.width == 736.0) // Both orientations
#define UI_IS_IOS8_AND_HIGHER ([[UIDevice currentDevice].systemVersion floatValue] >= 8.0)
使用时直接判断 例如if(UI_IS_IPHONE4）
