- (void)viewDidLoad{    [super viewDidLoad];    // Do any additional setup after loading the view.        //监听手机方向改变事件    [[NSNotificationCenter defaultCenter] addObserver:self                                             selector:@selector(orientationChanged)                                                 name:UIDeviceOrientationDidChangeNotification                                               object:nil];}//处理函数-(void) orientationChanged{    switch ([[UIDevice currentDevice] orientation]) {        case UIDeviceOrientationPortrait:            NSLog(@"portrait");            break;        case UIDeviceOrientationPortraitUpsideDown:            NSLog(@"portraitUpSideDown");            break;        case UIDeviceOrientationLandscapeLeft:            NSLog(@"landscapeLeft");            break;        case UIDeviceOrientationLandscapeRight:            NSLog(@"landscapeRight");            break;        case UIDeviceOrientationFaceDown:            NSLog(@"facedown!!");            break;        case UIDeviceOrientationFaceUp:            NSLog(@"FaceUp");            break;        default:             break;     } }