Load an image on specific date and time in iOS [closed] - ios

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My question is: how do I load a specific image on a specific date and time in iOS?
I have searched the net but did not find anything useful.
I have a list of images in an imageArray and want every image to be shown on a specific date, time and order.
Fx. say I want to load MyImage on MyDateAndTime. How can I do this?
Image 1 - DateAndTime 1
Image 2 - DateAndTime 2
Image 3 - DateAndTime 3
Any suggestions is appreciated, please provide some source code if possible.

Answer 1

I put simple logic, edit it as per your requirement otherwise if you have any query related to my answer then please tells to me.
Best way is store your image with Name of dateTime (dd_MM_yyyy_HH_mm_ss) and access image name such like,
NSString *imageName
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:#"dd_MM_yyyy_HH_mm_ss"];
imageName = [NSString stringWithFormat:#"%#.png", [formatter stringFromDate:[NSDate date]]]; // here you can set specific dateTime, i putted current dateTime
Here you get imageName such like 19_10_2013_6_13_21.png
And by this image name you can get image from bundle or document directory.

Answer 2

If all you want is to show a different image every minute, use this, otherwise skip below to see helpful date information.
NSTimeInterval secondsInMinute = 60;
[NSTimer timerWithTimeInterval:secondsInMinute target:self selector:#selector(minuteChanged:) userInfo:nil repeats:YES];
- (void)minuteChanged:(id)sender {
// change image here
}
You question could have many different answers, do you want to create this date dynamically? or is it a a predefined date? One solution is to get get the timeInterval of the date you are looking for.
NSDate* rightNow = [NSDate date];
NSTimeInterval timeInterval = [rightNow timeIntervalSince1970];
// since time intervals are in seconds we can just append the
// date as easily as adding time
NSInteger secondsInMinute = 60;
NSInteger minutesInHour = 60;
NSInteger hoursInDay = 24;
NSInteger daysInWeek = 7;
NSInteger secondsInWeek = secondsInMinute * minutesInHour * hoursInDay * daysInWeek;
timeInterval = timeInterval + secondsInWeek;
NSDate* aWeekInFuture = [NSDate dateWithTimeIntervalSince1970:timeInterval];
that i would say is the easiest to under stand to set a date, but you could also use components to set a future date dynamically. This leads into some problems but here is how it's done.
NSDate* rightNow = [NSDate date];
NSCalendar* calendar = [NSCalendar currentCalendar];
NSDateComponents* dateCompenents = [calendar components:(NSDayCalendarUnit | NSWeekCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit) fromDate:rightNow];
[dateCompenents setDay:dateCompenents.day + 7];
NSDate* aWeekInFuture = [calendar dateFromComponents:dateCompenents];
to help explain this, here is some console logs
(lldb) po rightNow
$0 = 0x0b933440 2013-10-19 12:43:55 +0000
(lldb) po aWeekInFuture
$1 = 0x0ba32a60 2013-10-26 04:00:00 +0000
you see how the date is accurate for the day, year, month, but look at the exact time, the current time (right now) is 12:43:55 but the week in he future is 4:00:00 this is because i did not ask for the NSMinutesCalendarUnit, NSHoursCalendarUnit, NSSecondsCalendarUnit... so if i wanted a perfect date that would be inadequate unless i ask for every single thing, but you specifically may not need to be so accurate in fact you may even want to set your own time.
Now if you want a static date, a date the user enters, you will need to use NSDateFormatter example below
NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setCalendar:currentCalendar];
[dateFormatter setDateFormat:#"mm/dd/yyyy"];
NSDate* birthdayDate = [dateFormatter dateFromString:#"10/05/2013"];
Now you wanted to know how would you know if today is the specified date that is saved. Lets say you stored the date in NSUserDefaults or on a server or some place, the easiest way to compare the dates is with the compare function of an NSDate
NSDate* rightNow = [NSDate date];
NSDate* storedDate = [[NSUserDefaults standardUserDefaults] objectForKey#"storedDate"] // some date from server, or UserDefaults
NSComparisonResult = [rightNow compare:storedDate];
this is a bit inadequate since it test for perfection but it will return values of NSOrderedSame if they are equal, NSOrderedDescending if storedDate is behind rightNow, and NSOrderedAscending if storedDate is in front of rightNow. This is all specific down to the time interval. If you just want a generic day, you will have to test it via components
NSDate* rightNow = [NSDate date];
NSDate* birthdayDate = [[NSUserDefaults standardUserDefaults] objectForKey#"birthday"]
NSDateComponents* todayComponents = [currentCalendar components:(NSDayCalendarUnit | NSMonthCalendarUnit) fromDate:rightNow];
NSDateComponents* birthdayComponents = [currentCalendar components:(NSDayCalendarUnit | NSMonthCalendarUnit) fromDate:birthdayDate];
BOOL dayIsTheSame = ( todayComponents.day == birthdayComponents.day );
BOOL monthIsTheSame = ( todayComponents.month == birthdayComponents.month );
BOOL todayIsBirthday = ( dayIsTheSame && monthIsTheSame );
if (todayIsBirthday) {
[self.imgViewBirthday setImage[UIImage imageNamed:#"cake.png"]];
}
In your question you specified an array of images, lets say you have a different image depending on which hour it is, or which minute, you would use the component, todayComponent.minute after asking for the NSMinutesCalendarUnit as the index of this array;
UIImage* currentImageToDisplay = [self.arrayOfImage objectAtIndex:todayComponent.minute];
self.imageView.image = currentImageToDisplay;
References:
NSDate,
NSDateFormatter,
NSDateComponents,
NSCalendar,
NSTimer

Answer 3

If I understood your problem now, one fancy approach using a recursive block you might check out is this:
#import <Foundation/Foundation.h>
#import <dispatch/dispatch.h>
int main(int argc, const char * argv[])
{
#autoreleasepool {
NSArray* dates = #[#1, #1, #1, #1, #1, #1, #1, #1, #1];
NSArray* urls = #[#"A", #"B", #"C", #"D", #"E", #"F", #"G", #"H", #"I"];
NSEnumerator* dateIter = [dates objectEnumerator];
NSEnumerator* urlIter = [urls objectEnumerator];
typedef void(^block_t)(NSEnumerator* dateIter, NSEnumerator* urlIter);
block_t asyncFunc;
__block __weak block_t _asyncFunc = asyncFunc = ^(NSEnumerator* dateIter, NSEnumerator* urlIter) {
NSNumber* date = [dateIter nextObject];
NSString* url = [urlIter nextObject];
if (date != nil && url != nil) {
double delayInSeconds = [date doubleValue];
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_global_queue(0, 0), ^(void){
NSLog(#"%#", url);
_asyncFunc(dateIter, urlIter);
});
}
else {
printf("\n");
return;
}
};
// start:
asyncFunc(dateIter, urlIter);
sleep (10);
}
return 0;
}
Note:
The "dates" are actually "delays" and the URLs are actually just strings in this example. You should be able to adjust this as you like. Of course, NSLog(#"%#", url); would actually display your image.
Also, the block asyncFunc is asynchronous!