Determine which time is next from a list of times - ios

Question

I have a JSON request which gives prayer times. How can I use Objective-C to work out which is next? The JSON looks like this:
{
address = "<null>";
city = "<null>";
country = UK;
"country_code" = GB;
daylight = 1;
for = daily;
items = (
{
asr = "5:22 pm";
"date_for" = "2013-7-1";
dhuhr = "1:01 pm";
fajr = "2:15 am";
isha = "11:47 pm";
maghrib = "9:24 pm";
shurooq = "4:39 am";
}
);
latitude = "50.9994081";
link = "http://muslimsalat.com/UK";
longitude = "0.5039011";
"map_image" = "http://maps.google.com/maps/api/staticmap?center=50.9994081,0.5039011&sensor=false&zoom=13&size=300x300";
"postal_code" = "<null>";
"prayer_method_name" = "Muslim World League";
"qibla_direction" = "119.26";
query = "51.000000,0.500000";
state = "<null>";
timezone = 0;
title = UK;
"today_weather" = {
pressure = 1020;
temperature = 14;
};
}
My code so far is:
-(CLLocationCoordinate2D) getLocation{
CLLocationManager *locationManager = [[[CLLocationManager alloc] init] autorelease];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
locationManager.distanceFilter = kCLDistanceFilterNone;
[locationManager startUpdatingLocation];
CLLocation *location = [locationManager location];
CLLocationCoordinate2D coordinate = [location coordinate];
return coordinate;
}
//class to convert JSON to NSData
- (IBAction)getDataFromJson:(id)sender {
//get the coords:
CLLocationCoordinate2D coordinate = [self getLocation];
NSString *latitude = [NSString stringWithFormat:#"%f", coordinate.latitude];
NSString *longitude = [NSString stringWithFormat:#"%f", coordinate.longitude];
NSLog(#"*dLatitude : %#", latitude);
NSLog(#"*dLongitude : %#",longitude);
//load in the times from the json
NSString *myURLString = [NSString stringWithFormat:#"http://muslimsalat.com/%#,%#/daily/5.json", latitude, longitude];
NSURL *url = [NSURL URLWithString:myURLString];
NSData *jsonData = [NSData dataWithContentsOfURL:url];
if(jsonData != nil)
{
NSError *error = nil;
id result = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&error];
NSArray *jsonArray = (NSArray *)result; //convert to an array
if (error == nil)
NSLog(#"%#", result);
NSLog(#"%#", jsonArray);
for (id element in jsonArray) {
NSLog(#"Element asr: %#", [element objectForKey:#"asr"]);
}
}
}
How can I get the current time and determine which prayer comes next?
Thank you!

Answer 1

You need to get the 'items' dictionary using [result objectForKey:#"items"]. Then convert the string values to NSDate's using an NSDateFormatter. Then, iterate through the new dictionary and find the time with the smallest time interval to now using [currentDate timeIntervalSinceNow]. This is your next prayer.

Answer 2

Get a list of the dates, then use an NSPredicate to filter that list to dates >= [NSDate date], then sort it ascending. Then the first item in the filtered, sorted array will be the next date.

Answer 3

Read Apple's Date and Time Programming Guide. You will find methods to convert you string times ("2:15am" etc.) into NSDate objects, methods to get the current date and time (e.g. [NSDate new] return the current date and time), and methods for comparing date/times so you can find the next one.