如何在iOS中的特定时间启动和停止计时器

Question

My app detect the audio at particular intervel like 10:00AM(startTime) -10:30AM(endTime),etc.Now when the current time reaches start time(means current time is also 10:00 AM) how to call audio detection process and stop detection process at (endTime)10:30 AM . suppose another interval start at 10:15AM(startTime) - 10:45 AM(endTime) how to update endTime from 10:30AM to 10:45AM.how to check when current time reaches startTime and endTime.Please help me its urgent.Thanks here my code is

ViewController.h

@interface ViewController : UIViewController

{

  BOOL IsListening;

}

//session array is array of dictionaries contains program start and end time.

   ViewController.m

   -(void)viewDidLoad
   {

     [super viewDidLoad];

     NSTimer* listener_timer = [NSTimer scheduledTimerWithTimeInterval: 10.0 target: self
                                                  selector: @selector(listeningHandler:) userInfo: nil repeats: YES];

    }

   -(void)listeningHandler:(NSTimer*)time
    {

       if (!IsListening)
       {
          double currentTime=[[NSDate date] timeIntervalSince1970];

          for (NSDictionary * session in SessionsArray)
          {
            double startTime=[[session objectForKey:@“startTime”] doubleValue];
            double endTime=[[session objectForKey:@“endTime”] doubleValue];

            if (currentTime > startTime && currentTime < endTime)
            {
             //start listening.

              IsListening =YES;


              /*

             //detection process code

             */                 
               NSDate *fireDate = [NSDate dateWithTimeIntervalSinceNow:endTime];
               NSTimer *timer = [[NSTimer alloc] initWithFireDate:fireDate
                                                       interval:5
                                                         target:nil
                                                       selector:@selector(fireEndtimeAlarm)
                                                       userInfo:nil
                                                        repeats:YES];

              NSRunLoop *runLoop = [NSRunLoop currentRunLoop];
             [runLoop addTimer:timer forMode:NSDefaultRunLoopMode];

            }

          }

       }
      else
      {

         double currentTime=[[NSDate date] timeIntervalSince1970];
         for (NSDictionary * session in SessionsArray)
         {
            double startTime=[[session objectForKey:@"startTime"] doubleValue];
            double endTime=[[session objectForKey:@"endTime”] doubleValue];

            if (currentTime > startTime && currentTime < endTime)
            {
            // in between session

               IsListening =YES;
            /*

             //detection process code

             */          

             }

         }

       }
  }

 -(void)fireEndtimeAlarm

  {

     IsListening = NO;

     //stop detecting process at endTime  

  }

Answer 1

Start Timer & Stop Timer in ios

start Timer
timer= [NSTimer scheduledTimerWithTimeInterval:60.0f
                                            target: self
                                          selector: @selector(methodFromTimer)
                                          userInfo: nil
                                           repeats: YES];

stop timer

[timer invalidate];
timer=nil;

Answer 2

You can achieve this using 2 Local notifications

First of All schedule a specific notification at a specific time when time is reached then a trigger will run and at that time Start audio and

Schedule a second notification after 30 min when that will be fired then stop audio

For local notifications you can follow these

Link1

Link2