ios - 如何在 iOS 中的特定时间启动和停止计时器

Question

我的应用程序在特定时间检测音频，例如 10:00AM(startTime) -10:30AM(endTime) 等。现在当当前时间到达开始时间(意味着当前时间也是上午 10:00)时如何调用音频检测过程并在 (endTime)10:30 AM 停止检测过程。假设另一个时间间隔从 10:15AM(startTime) - 10:45AM(endTime) 开始，如何将 endTime 从 10:30AM 更新到 10:45AM。如何检查当前时间何时到达 startTime 和 endTime。请帮我解决紧急问题。谢谢我的代码是

ViewController.h

@interface ViewController : UIViewController

{

  BOOL IsListening;

}

//session数组是包含程序开始和结束时间的字典数组。

   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

在 ios 中启动定时器和停止定时器

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

stop timer

[timer invalidate];
timer=nil;