Question

how to integrate countdown and alarm in xcode iphone? please provide source code…..
i have tried a lot…but didn’t find any specific solution…please help me…

Answer 1

A countdown would not be very hard to integrate, just use an NSTimer:

NSTimer *countdown = [NSTimer timerWithTimeInterval:1.0 target:self selector:@selector(timerTicked:) userInfo:nil repeats:YES]; 

Simply countdown the timer for as many seconds as you want:

- (void)timerTicked:(NSTimer *)countdown{
    seconds--; // Some pre-declared variable

    // UI Updates Here if you want

    if (seconds <= 0)
        [countdown invalidate]; 
}

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An alarm would be a little more complicated, but still not too hard. There’s a few ways you could do it depending how you are setting the alarm. If it’s soon just use a timer:

NSTimer *alarm = [NSTimer timerWithTimeInterval:SECONDS target:self selector:@selector(alarmDoneMethod) userInfo:nil repeats:NO];

However I’m assuming for an alarm you want it to be able to be set hours or days in the future. In this case use an NSDate.

NSDateComponents *alarmComponents = [[NSDateComponents alloc] init]; 
[alarmComponents setMinute:userInputMinute];
[alarmComponents setHour:userInputHour]; 
[alarmComponents setDay:userInputDay];
[alarmComponents setMonth:userInputMonth];
[alarmComponents setYear:userInputYear];

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

NSDate *alarm = [gregorian dateFromComponents:alarmComponents];
[alarmComponents release]; 

Now just set a timer (I’m sure there is a more efficient way of doing this but I can’t think of it off the top of my head at the moment, it’s still early in the day) to check if your alarm has been reached:

NSTimer *checkAlarm = [NSTimer timerWithTimeInterval:60.0 target:self selector:@selector(checkAlarm:) userInfo:nil repeats:YES]; // Checks every minute

Then inside the checkAlarm: method just see if the alarm has been reached:

-(void)checkAlarm:(NSTimer *)t{
    if ([[NSDate date] earlierDate:alarm] == alarm){
        // Alarm reached
        [t invalidate]; 
    }
}

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Hope this helps.

Cheers.