ios 监听设备方向发生改变

1.添加监听函数
[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
        [[NSNotificationCenter defaultCenter] addObserver:self
        
                                                 selector:@selector(deviceOrientationDidChange:)
        
                                                     name:UIDeviceOrientationDidChangeNotification
        
                                                   object:nil];
2.得到设备对象
  -(void)deviceOrientationDidChange:(NSObject*)sender{
    UIDevice* device = [sender valueForKey:@"object"];
    NSLog(@"%d",device.orientation);
   
}