Question

I’m diving into iPhone development and I’m trying to get my head around gestures and the touch events. How can I measure how fast the user is moving their finger across the screen of an iOS device using the touche events (touchesBegan, touchesMoved, etc)?

Thanks so much in advance for your help!

Answer 1

You can do that by using the timestamp property of UITouch class. The property is described as:

The value of this property is the
time, in seconds, since system startup
the touch either originated or was
last changed. You can store and
compare the initial value of this
attribute to subsequent timestamp
values of the UITouch instance to
determine the duration of the touch
and, if it is being swiped, the speed
of movement.

UITouch Class Reference