如何在应用程序的后台运行计时器？ [英] How to run the timer in background of the application?

问题描述

我想减少时间倒计时。因此，如果用户最小化应用，则应用加载背景。如何在应用程序后台运行计时器？我使用以下代码。当app最小化时，计时器停止。请帮帮我。

I want to reduce the count down of the time. So If the user minimize app then app loading the background. How can run the timer in application background? I am using the below code. When app is minimized timer is stopped. Please help me.

        timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(timerCountDown) userInfo:nil repeats:YES];

- (void)timerCountDown
{
    if(secondsLeft > 0 ) {
        secondsLeft -- ;
        hours = secondsLeft / 3600;
        minutes = (secondsLeft % 3600) / 60;
        seconds = (secondsLeft %3600) % 60;
    }
}

推荐答案

我得到了答案，它完美地工作。

I got the answer, its working perfectly.

UIBackgroundTaskIdentifier bgTask =0;
UIApplication  *app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
    [app endBackgroundTask:bgTask];
}];

timer = [NSTimer
               scheduledTimerWithTimeInterval:1.0
               target:self
               selector:@selector(timerCountDown:)
               userInfo:nil
               repeats:YES];

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