iOS 监听横屏竖屏

/**
     *  开始生成 设备旋转 通知
     */
    [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];


    /**
     *  添加 设备旋转 通知
     *  
     *  当监听到 UIDeviceOrientationDidChangeNotification 通知时，调用handleDeviceOrientationDidChange:方法
     *  @param handleDeviceOrientationDidChange: handleDeviceOrientationDidChange: description
     *
     *  @return return value description
     */
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(handleDeviceOrientationDidChange:)
                                                 name:UIDeviceOrientationDidChangeNotification
                                               object:nil
     ];


/**
     *  销毁 设备旋转 通知
     *
     *  @return return value description
     */
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UIDeviceOrientationDidChangeNotification
                                                  object:nil
     ];


    /**
     *  结束 设备旋转通知
     *
     *  @return return value description
     */
    [[UIDevice currentDevice]endGeneratingDeviceOrientationNotifications];


- (void)handleDeviceOrientationDidChange:(UIInterfaceOrientation)interfaceOrientation
{
    //1.获取 当前设备 实例
    UIDevice *device = [UIDevice currentDevice] ;




    /**
     *  2.取得当前Device的方向，Device的方向类型为Integer
     *
     *  必须调用beginGeneratingDeviceOrientationNotifications方法后，此orientation属性才有效，否则一直是0。orientation用于判断设备的朝向，与应用UI方向无关
     *
     *  @param device.orientation
     *
     */

    switch (device.orientation) {
        case UIDeviceOrientationFaceUp:
            NSLog(@"屏幕朝上平躺");
            break;

        case UIDeviceOrientationFaceDown:
            NSLog(@"屏幕朝下平躺");
            break;

            //系統無法判斷目前Device的方向，有可能是斜置
        case UIDeviceOrientationUnknown:
            NSLog(@"未知方向");
            break;

        case UIDeviceOrientationLandscapeLeft:
            NSLog(@"屏幕向左横置");
            break;

        case UIDeviceOrientationLandscapeRight:
            NSLog(@"屏幕向右橫置");
            break;

        case UIDeviceOrientationPortrait:
            NSLog(@"屏幕直立");
            break;

        case UIDeviceOrientationPortraitUpsideDown:
            NSLog(@"屏幕直立，上下顛倒");
            break;

        default:
            NSLog(@"无法辨识");
            break;
    }

}