cocoa-touch - CMMotionManager 检测设备何时静止

Question

如何设置处理，以便我可以检测设备何时静止（在某个阈值中）

下面的代码没有按预期工作（userAcceleration 只是更大，取决于设备方向，用户甚至不移动设备（这个值可能来自重力））

self.motionManager = [[CMMotionManager alloc] init];
        self.motionManager.accelerometerUpdateInterval = 1/2.0;
        [self.motionManager startAccelerometerUpdatesToQueue:[NSOperationQueue currentQueue] withHandler:^(CMAccelerometerData *accelerometerData, NSError *error) {

            float accelerationThreshold = 0.75;
            CMAcceleration userAcceleration = accelerometerData.acceleration;
            if ((fabs(userAcceleration.x) > accelerationThreshold)
                || (fabs(userAcceleration.y) > accelerationThreshold)
                || (fabs(userAcceleration.z) > accelerationThreshold)) {
                self.deviceMoved = YES;
            } else {
                self.deviceMoved = NO;
            }

        }];

Answer 1

需要使用 startDeviceMotionUpdatesToQueue

if (self.motionManager == nil) {
        self.motionManager = [[CMMotionManager alloc] init];
        self.motionManager.accelerometerUpdateInterval = 1/2.0;
        [self.motionManager startDeviceMotionUpdatesToQueue:[NSOperationQueue currentQueue] withHandler:^(CMDeviceMotion *motion, NSError *error) {

            float accelerationThreshold = 0.25;
            CMAcceleration userAcceleration = motion.userAcceleration;
            if ((fabs(userAcceleration.x) > accelerationThreshold)
                || (fabs(userAcceleration.y) > accelerationThreshold)
                || (fabs(userAcceleration.z) > accelerationThreshold)) {
                self.deviceMoved = YES;
            } else {
                self.deviceMoved = NO;
            }

        }];
    }