这几天做App的时候，需要添加旋转屏通知以便调整UI布局

刚开始我使用的是UIDeviceOrientationDidChangeNotification，

一直有一些问题就是，如果使用这个通知，当iPhone/iPad旋转的时候，你会得到的旋转方向会是所有的

UIDeviceOrientationUnknown和UIDeviceOrientationFaceUp等

 

typedef enum {
    UIDeviceOrientationUnknown,
    UIDeviceOrientationPortrait,            // Device oriented vertically, home button on the bottom
    UIDeviceOrientationPortraitUpsideDown,  // Device oriented vertically, home button on the top
    UIDeviceOrientationLandscapeLeft,       // Device oriented horizontally, home button on the right
    UIDeviceOrientationLandscapeRight,      // Device oriented horizontally, home button on the left
    UIDeviceOrientationFaceUp,              // Device oriented flat, face up
    UIDeviceOrientationFaceDown             // Device oriented flat, face down
} UIDeviceOrientation;

但是我不需要对

UIDeviceOrientationUnknown和UIDeviceOrientationFaceUp

进行处理，所以有时候就会出错，

后来更改为通知UIApplicationDidChangeStatusBarFrameNotification

在只有status更改位置的时候你才会收到通知，即你此时得到的方向只会是

 

[cpp]

      UIDeviceOrientationPortrait
UIDeviceOrientationPortraitUpsideDown
UIDeviceOrientationLandscapeLeft
UIDeviceOrientationLandscapeRight