Is there an easy way to get a time very precisely?
I need to calculate some delays between method calls. More specifically, I want to calculate the speed of scrolling in an UIScrollView.
NSDate
and the timeIntervalSince*
methods will return a NSTimeInterval
which is a double with sub-millisecond accuracy. NSTimeInterval
is in seconds, but it uses the double to give you greater precision.
In order to calculate millisecond time accuracy, you can do:
// Get a current time for where you want to start measuring from
NSDate *date = [NSDate date];
// do work...
// Find elapsed time and convert to milliseconds
// Use (-) modifier to conversion since receiver is earlier than now
double timePassed_ms = [date timeIntervalSinceNow] * -1000.0;
Documentation on timeIntervalSinceNow.
There are many other ways to calculate this interval using NSDate
, and I would recommend looking at the class documentation for NSDate
which is found in NSDate Class Reference.