Get progress of day in Objective-C - ios

Question

I need to get the progress of the current day (For example from 6am and 11pm). I have tried many things and the only code I can get working so far is this code:
//Get the seconds between two days
//Get todays date
NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear fromDate:[NSDate date]];
//Set todays date in a NSCalendar object
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDate *date1 = [gregorian dateFromComponents:components];
//Get tomorrows date
NSDateComponents *components1 = [[NSCalendar currentCalendar] components:NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear fromDate:[NSDate date]];
components1.day++;
//Set tomorrows date in a NSCalendar object
NSDate *date2 = [gregorian dateFromComponents:components1];
NSTimeInterval secondsBetween = [date2 timeIntervalSinceDate:date1];
NSLog(#"Test: %f", secondsBetween);
This code will get the amount of seconds between two days in total (which doesn't really matter as it's a constant). How do I get the progress between two different times? As the user will be allowed to change the times it counts between I need to be able to calculate this on the fly in a NSTimer.
Edit: I want to know how to use a ProgressView to display the percentage between two times. E.g. The ProgressView would be 50% if it was 9AM and the times were 6AM and 12PM.

Answer 1

The difference in seconds between two dates is
[date2 timeIntervalSinceDate:date1];
That seems to be all you need for your problem.

Answer 2

you only set day/month/year -- set hours/minutes/seconds too.
right now the dates always point to 00:00:00 and not to any TIME

Answer 3

No problem. I use the following method to determine the difference between NSDate values:
- (NSInteger)secondsBetweenDate:(NSDate*)fromDateTime andDate:(NSDate*)toDateTime {
NSDate *fromDate;
NSDate *toDate;
NSCalendar *calendar = [NSCalendar currentCalendar];
//Returns by reference the starting time and duration for the given dates (with second precision).
[calendar rangeOfUnit:NSCalendarUnitSecond startDate:&fromDate
interval:NULL forDate:fromDateTime];
[calendar rangeOfUnit:NSCalendarUnitSecond startDate:&toDate
interval:NULL forDate:toDateTime];
//Returns the difference between the two dates (with second precision)
NSDateComponents *difference = [calendar components:NSCalendarUnitSecond
fromDate:fromDate toDate:toDate options:0];
//returns the number of seconds
return [difference second];
}
To test the above code, I've used an easier way to create two points in time (rather than many lines you've used above). This is simply used to test and you'll obviously use real values in your actual code
NSDate * myDate1 = [NSDate date]; // date as of right now
NSDate * myDate2 = [[NSDate alloc] initWithTimeIntervalSinceNow:1 * 24 * 60 * 60]; // exactly 24 hours into the future
NSLog(#"Second Between: %ld",(long)[self secondsBetweenDate:myDate1 andDate:myDate2]);
//OUTPUT: Seconds: 86400
You can easily tweak the values above to test certain ranges. For reference, this is what each number stands for:
1 (days) * 24 (hours) * 60 (minutes) * 60 (seconds)
OK, with that sorted you just need to figure out how much time has progressed since your starting time. You can do that with two calls to the method created at the start of this post:
//Assuming dates are sourced from some other code
NSDate * startTime // Set elsewhere in the code
NSDate * currentTime // Set elsewhere in the code
NSDate * endTime // Set elsewhere in the code
long fullDuration = [self secondsBetweenDate:startTime andDate:endTime];
long timeElapsed = [self secondsBetweenDate:startTime andDate:currentTime];
float percentComplete = (float) timeElapsed / (float) fullDuration;
Now, since we're going to be using ProgressView I'm keep this percent value as a number between 0 and 1 and the variable as a float.
Finally, assuming you already have the following done:
Added a ProgressView object to your storyboard
Added an outlet to to the object called something like progressViewOutlet
All you need to do is send the update regularly using your timer using the following code:
self.progressViewOutlet.progress = percentComplete;
You can grab my source code below. Let me know if you have any questions
https://dl.dropboxusercontent.com/u/43038596/testDates.zip