iOS 监听手机屏幕旋转

监听屏幕旋转

首先所要监听的NSNotificationName是UIApplicationDidChangeStatusBarOrientationNotification而非UIDeviceOrientationDidChangeNotification，因为UIDeviceOrientationDidChangeNotification在应用进入后台applicationDidEnterBackground和进入前台applicationWillEnterForeground同样会响应通知，通常我们不需要程序在进入后台、前台进行屏幕旋转，这就可能会造成可能的界面错乱，所以正确的做法是：

1. 添加通知[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(statusBarOrientationChanged:) name:UIApplicationDidChangeStatusBarOrientationNotification object:nil];
   2.实现通知方法
   – (void)statusBarOrientationChanged:(NSNotification )noti {
   /
   UIInterfaceOrientationUnknown = UIDeviceOrientationUnknown,
   UIInterfaceOrientationPortrait = UIDeviceOrientationPortrait,
   UIInterfaceOrientationPortraitUpsideDown = UIDeviceOrientationPortraitUpsideDown,
   UIInterfaceOrientationLandscapeLeft = UIDeviceOrientationLandscapeRight,
   UIInterfaceOrientationLandscapeRight = UIDeviceOrientationLandscapeLeft
   */
   UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
   if (orientation == UIInterfaceOrientationLandscapeLeft) {//

   }
   if (orientation == UIInterfaceOrientationLandscapeRight) {

   }
   if (orientation == UIInterfaceOrientationPortrait) {

   }

}