小编Bat*_*tti的帖子

我正在尝试CoreMotion的新功能,首先是设置参考帧的可能性,但是如果我使用DeviceMotionHandler并且参考帧设置为CMAttitudeReferenceFrameXTrueNorthZVertical,则输出是CMAttitudeReferenceFrameXArbitraryCorrectedZVertical中的一些.我启动应用程序时,iphone始终处于与我的桌面相同的偏航旋转,并且我测试不同的初始偏航旋转,但结果始终相同.

motionManager = [[CMMotionManager alloc] init];
motionManager.showsDeviceMovementDisplay = YES;
motionManager.deviceMotionUpdateInterval = 1.0/60.0;    

CMDeviceMotionHandler  motionHandler = ^ (CMDeviceMotion *motion, NSError *error) {
    NSLog(@"%f      %f         %f", motion.attitude.pitch, motion.attitude.roll, motion.attitude.yaw);
};

[motionManager startDeviceMotionUpdatesUsingReferenceFrame:CMAttitudeReferenceFrameXTrueNorthZVertical toQueue:[NSOperationQueue currentQueue] withHandler:motionHandler];

我找到了我的问题的解决方案,但我无法理解为什么以前的代码不起作用.我在motionHandler中只添加了一个CMAttitude变量*a.

- (void)viewDidLoad
{
[super viewDidLoad];
motionManager = [[CMMotionManager alloc] init];
motionManager.showsDeviceMovementDisplay = YES;
motionManager.deviceMotionUpdateInterval = 1.0/60.0;    

CMDeviceMotionHandler  motionHandler = ^ (CMDeviceMotion *motion, NSError *error) {
    CMAttitude *a = motionManager.deviceMotion.attitude;
    labelAngle.text = [NSString stringWithFormat:@"%f      %f         %f",a.pitch, a.roll,a.yaw];
    labelAngle2.text = [NSString stringWithFormat:@"%f       %f      %f", motion.attitude.pitch, motion.attitude.roll, motion.attitude.yaw];
}; …

分析deviceMotion.timestamp我发现DeviceMotion中设置的更新频率不是实际的更新频率.

我实现了一个应用程序,以便测试,低于我所看到的!

    update frequency     actual frequency       average time between two calls
       1/10.000000          10.232265              0.097730
       1/20.000000          19.533729              0.051194
       1/30.000000          30.696613              0.032577
       1/40.000000          42.975122              0.023269
       1/50.000000          53.711000              0.018618
       1/60.000000          53.719106              0.018615
       1/70.000000          71.627016              0.013961
       1/80.000000          71.627263              0.013961
       1/90.000000          53.719365              0.018615
       1/100.000000        107.442667              0.009307
       1/110.000000        107.437022              0.009308

有人注意到了同样的事情吗？这是一个错误吗？