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];
}