You can think of it like this:
You are in your room (aka your IOS program), and you are not where you can see the accelerometer readings directly. Your buddy is in his room (aka the Bean) and can get up, walk across the room and look at the accelerometer readings when you need him to.
So, when you call
readAccelerationAxes() it is like sending your buddy a text message and asking him to text you back with the accelerometer readings. Meanwhile, you can go on doing other tasks.
When your buddy texts you back the
didUpdateAccelerationAxes() function executes and the
acceleration parameter has the acceleration readings in it. If you want him to send you another set of readings right away, you call
readAccelerationAxes() again from within
didUpdateAccelerationAxes(). You do not have any control over how long it takes your buddy to text you back, so the time between
didUpdateAccelerationAxes() may vary.
You do not need to call
readAccelerationAxes() from within
didUpdateAccelerationAxes(); you could call
readAccelerationAxes() via a timer, in response to a button press, etc. However, for each call to
readAccelerationAxes() you should see