Question

如果我放下我的Apple Watch并在它撞到地面之前抓住它，我正在制作的应用程序会检测到手表已经掉落。但那并没有发生。下面的代码有什么问题？谢谢！

let motion = CMMotionManager()
if motion.isDeviceMotionAvailable {
     motion.deviceMotionUpdateInterval = 0.1
     motion.startDeviceMotionUpdates()
     if let deviceMotion = motion.deviceMotion {
          let accelerationX = deviceMotion.gravity.x + deviceMotion.userAcceleration.x
          let accelerationY = deviceMotion.gravity.y + deviceMotion.userAcceleration.y
          let accelerationZ = deviceMotion.gravity.z + deviceMotion.userAcceleration.z
          let totalAcceleration = sqrt((accelerationX * accelerationX) + (accelerationY * accelerationY) + (accelerationZ * accelerationZ))

          if totalAcceleration >  9.0 {
               print("Watch has fallen")
          }
    }
    motion.stopDeviceMotionUpdates()
}

Answer 1

motion.deviceMotion将获取最新的设备运动数据样本。

因此，这可能只是在您运行数据时获取数据。你可能需要像计时器这样的东西来检查加速度。

这样的事情（取自https://developer.apple.com/documentation/coremotion/getting_raw_accelerometer_events）

let motion = CMMotionManager()

func startAccelerometers() {
   // Make sure the accelerometer hardware is available. 
   if self.motion.isAccelerometerAvailable {
      self.motion.accelerometerUpdateInterval = 1.0 / 60.0  // 60 Hz
      self.motion.startAccelerometerUpdates()

      // Configure a timer to fetch the data.
      self.timer = Timer(fire: Date(), interval: (1.0/60.0), 
            repeats: true, block: { (timer) in
         // Get the accelerometer data.
         if let data = self.motion.accelerometerData {
            let x = data.acceleration.x
            let y = data.acceleration.y
            let z = data.acceleration.z

            // Use the accelerometer data in your app.
         }
      })

      // Add the timer to the current run loop.
      RunLoop.current.add(self.timer!, forMode: .defaultRunLoopMode)
   }
}

或者，您也可以将处理程序传递给startDeviceMotionUpdates，该处理程序将根据deviceMotionUpdateInterval进行调用。

检测佩戴Apple Watch的人何时跌倒

1 个答案: