How can i handle distance through accelerometer?

My object starts from zero.开发者_开发知识库 When the time goes..It covers some distance, so how can I measure this?

Oh, it's simple. All you have to do is implement an Inertial Measurement Unit and then an Inertial Navigation System. It's going to be hard to do without rotation sensors, it would probably require a Kalman Filter for accuracy, and typically it is done with ring laser gyros or fiber optic gyros, which are "solid state" devices that work by measuring relativistic effects and sell for rather higher prices than the silicon micromachined sensors in the iPhone, but you might get it to work.

Or, you could just use the GPS.

Other than just being alerted that the device did move, the accelerometer will not be much use. You will not get a reading of "device moved 10cm" or something similar, as far as I know you'll just get a value for how much acceleration occurred.

If you need to track your device's movement in the physical world you'll need to use the Location APIs.

You can figure this out, but it won't be that accurate, mainly due to sample rate and the inaccuracy of the accelerometer.

First figure out direction and force of the movement. If the user moves the iphone at +0.1G along the X axis and 0G along the Y and Z axis, then our force is +0.1G on the X axis. 1G is 9.8m/s, so the phone has move 0.9m if it has been traveling for 1 second.