IOS 特定于设备的开发：获取和使用设备姿势（通过手机方向控制3d物体显示）

利用设备的机载陀螺仪可以实现，当你旋转手机屏幕时，里面的画面不会随着视图更新而移动，以平衡物理运动。

下面例子利用少量简单的几何变换执行该操作。他建立一个运动管理器，订阅设备运动更新，然后基于运动管理器返回的摇晃，前倾和左右摇摆的角度应用图像变换。

@implementation TestBedViewController

{

    CMMotionManager *motionManager;

    UIImageView *imageView;

}



- (void) shutDownMotionManager

{

    NSLog(@"Shutting down motion manager");

    [motionManager stopDeviceMotionUpdates];

    motionManager = nil;

}



- (void) establishMotionManager

{

    if (motionManager)

        [self shutDownMotionManager];

    

    NSLog(@"Establishing motion manager");

    

    // Establish the motion manager

    motionManager = [[CMMotionManager alloc] init];

    if (motionManager.deviceMotionAvailable)

        [motionManager

         startDeviceMotionUpdatesToQueue:[NSOperationQueue currentQueue]

         withHandler: ^(CMDeviceMotion *motion, NSError *error) {

             CATransform3D transform;

             transform = CATransform3DMakeRotation(motion.attitude.pitch, 1, 0, 0);

             transform = CATransform3DRotate(transform, motion.attitude.roll, 0, 1, 0);

             transform = CATransform3DRotate(transform, motion.attitude.yaw, 0, 0, 1);

             imageView.layer.transform = transform;

         }];

}



- (void) viewDidAppear: (BOOL) animated

{

    NSString *imageName = IS_IPAD ? @"iPadArt.png" : @"iPhoneArt.png";

    UIImage *image = [UIImage imageNamed:imageName];

    imageView = [[UIImageView alloc] initWithImage:image];

    imageView.center = RECTCENTER(self.view.bounds);

    [self.view addSubview:imageView];

}



- (void) loadView

{

    [super loadView];

    self.view.backgroundColor = [UIColor whiteColor];

}