竖屏
CurrentDeviceVersion: 9.1
CurrentInterfaceOrientation:UIDeviceOrientationPortrait
[UIScreen mainScreen].bounds: {{0, 0}, {375, 667}}
[UIScreen mainScreen].applicationFrame: {{0, 20}, {375, 647}}
[UIScreen mainScreen].fixedCoordinateSpace.bounds: {{0, 0}, {375, 667}}

横屏
CurrentDeviceVersion: 9.1
CurrentInterfaceOrientation:UIInterfaceOrientationLandscapeLeft
[UIScreen mainScreen].bounds: {{0, 0}, {667, 375}}
[UIScreen mainScreen].applicationFrame: {{0, 20}, {667, 355}}
[UIScreen mainScreen].fixedCoordinateSpace.bounds: {{0, 0}, {375, 667}}

比较系统版本

define SYSTEM_VERSION_EQUAL_TO(v) ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedSame)

define SYSTEM_VERSION_GREATER_THAN(v) ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedDescending)

define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v) ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)

define SYSTEM_VERSION_LESS_THAN(v) ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedAscending)

define SYSTEM_VERSION_LESS_THAN_OR_EQUAL_TO(v) ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedDescending)