1.手机朝向的枚举
typedef NS_ENUM(NSInteger, UIDeviceOrientation) {
UIDeviceOrientationUnknown,
UIDeviceOrientationPortrait, // 设备面向垂直，home 按钮在底部
UIDeviceOrientationPortraitUpsideDown, // Device oriented vertically, home button on the top
UIDeviceOrientationLandscapeLeft, // 设备面向垂直，home 按钮在顶部
UIDeviceOrientationLandscapeRight, // 设备水平，面向 home 按钮在左边
UIDeviceOrientationFaceUp, // 设备平，面向脸了
UIDeviceOrientationFaceDown // 设备平，面向的脸
} __TVOS_PROHIBITED;
2.可以使用switch来记录设备的方向
获取设备方向的枚举值
[[UIDevice currentDevice] orientation]
switch ([[UIDevice currentDevice] orientation])
{
case UIDeviceOrientationPortraitUpsideDown:
break;
case UIDeviceOrientationLandscapeLeft:
break;
case UIDeviceOrientationLandscapeRight:
break;
case UIDeviceOrientationFaceUp:
default:
break;
}