/**判断是否系统版本大于8.0系统  大于或等于8.0返回true 否则返回false*/

let IS_IOS8 = (UIDevice.currentDevice().systemVersion as NSString).doubleValue >= 8.0

let IS_OS_5_OR_LATER = (UIDevice.currentDevice().systemVersion as NSString).doubleValue >= 5.0

let IS_OS_6_OR_LATER = (UIDevice.currentDevice().systemVersion as NSString).doubleValue >= 6.0

let IS_OS_7_OR_LATER = (UIDevice.currentDevice().systemVersion as NSString).doubleValue >= 7.0

let IS_IPAD = (UIDevice.currentDevice().userInterfaceIdiom == .Pad)

let IS_IPHONE = (UIDevice.currentDevice().userInterfaceIdiom == .Phone)

let SCREEN_MAX_LENGTH = (max(SCREEN_WIDTH, SCREEN_HEIGHT))

let SCREEN_MIN_LENGTH = (min(SCREEN_WIDTH, SCREEN_HEIGHT))

let IS_IPHONE_4_OR_LESS = (IS_IPHONE && SCREEN_MAX_LENGTH < 568.0)

let IS_IPHONE_5 = (IS_IPHONE && SCREEN_MAX_LENGTH  == 568.0)

let IS_IPHONE_6 = (IS_IPHONE && SCREEN_MAX_LENGTH  == 667.0)

let IS_IPHONE_6P = (IS_IPHONE && SCREEN_MAX_LENGTH == 736.0)