需求：IOS横竖屏幕切换

需求：IOS监听横竖屏幕切换，并做相应布局调整。

实现：

1、设置监听横竖屏切换动作

[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didRotate:) name:UIApplicationDidChangeStatusBarOrientationNotification object:nil];
orientation = (UIDeviceOrientation)[UIApplication sharedApplication].statusBarOrientation; //This is more reliable than (self.interfaceOrientation) and [[UIDevice currentDevice] orientation] (which may give a faceup type value)
if (orientation == UIDeviceOrientationUnknown || orientation == UIDeviceOrientationFaceUp || orientation == UIDeviceOrientationFaceDown)
{
orientation = UIDeviceOrientationPortrait;
}

2、UI布局处理

-(void)didRotate:(NSNotification *)notification{

UIDeviceOrientation newOrientation = [[UIDevice currentDevice] orientation];
if (newOrientation != UIDeviceOrientationPortraitUpsideDown && newOrientation != UIDeviceOrientationUnknown && newOrientation != UIDeviceOrientationFaceUp && newOrientation != UIDeviceOrientationFaceDown && newOrientation != orientation){
orientation = newOrientation;
[self initWindowViews];
}
}
3、兼容性问题（网上例子，但没有测试），不加暂没发现任何问题。

// iOS5.0
-(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation{
return UIInterfaceOrientationMaskAllButUpsideDown; // 可以修改为任何方向
}

-(NSUInteger)supportedInterfaceOrientations{
return UIInterfaceOrientationMaskAllButUpsideDown; // 可以修改为任何方向
}

-(BOOL)shouldAutorotate{
return YES;
}

参考网址：

http://blog.csdn.net/openglnewbee/article/details/40404495

例子

https://github.com/Thinkerfans/ios-screenrotate-demo.git