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iphoneobjective-cnsstringnstimeinterval

converting NSString to precise number for performSelector: afterDelay:

I am communicating with a webservice to retrieve a numerical value that comes into my function as an NSString. This number tells me the precise amount of time to wait until I perform another action, and it is critical that it be precise.

As an example, if the string is "89283", then this means I must wait 89.283 seconds. So I'd like to know the best way in Objective-C for iPhone to convert this string to a precise value that I can pass to the performSelector:afterDelay: function. Here's my sample code, but I'm guessing its not accurate.

NSString *myDelayString = @"89283";
int myDelay = [myDelayString intValue]/1000;
[self performSelector:@selector(myFunction) withObject:nil afterDelay:myDelay];

I think the myDelay value really should be a NSTimeInterval, but I'm not sure how to make that from the string I have. Thanks in advance.

Solution

  • Here is the code with changes to allow double precision.

    NSString *myDelayString = @"89283";
NSTimeInterval myDelay = [myDelayString doubleValue]/1000;
[self performSelector:@selector(myFunction) withObject:nil afterDelay:myDelay];

    Use doubleValue in order to get the string as a double so you can avoid integer division. NSTimeInterval's type is defined as a double on the iphone, so you can store the double result into it and then pass it to the afterDelay: part of the selector.