ios - 无法转换类型的值(CMAccelerometerData!，NSError!)

Question

它一直说 Cannot convert value of type (CMAccelerometerData!, NSError!) 。我该如何更改它？

motionManager.startAccelerometerUpdatesToQueue(NSOperationQueue.currentQueue()!, withHandler: {
            (accelerometerData: CMAccelerometerData!, error: NSError!) in
            // 3
            let acceleration = accelerometerData.acceleration
            // 4
            self.xAcceleration = (CGFloat(acceleration.x) * 0.75) + (self.xAcceleration * 0.25)
            })

Answer 1

让编译器推断闭包中的类型:

CMMotionManager().startAccelerometerUpdatesToQueue(NSOperationQueue.currentQueue()!) { (accelerometerData, error) in
    //
}