ios - Getting time elapsed in Objective-C

Question

I need to get the time elapsed between two events, for example, the appearance of a UIView and the user's first reaction.

How can I achieve it in Objective-C?

Answer 1

NSDate *start = [NSDate date];
// do stuff...
NSTimeInterval timeInterval = [start timeIntervalSinceNow];

timeInterval is the difference between start and now, in seconds, with sub-millisecond precision.