可以使用后台服务（Background service）来解决该问题。后台服务是指即使应用程序处于后台或被杀死，仍然可以继续在后台运行的服务。

以下是一个示例代码，说明如何创建一个后台服务来实现计时器功能：

首先，需要在Manifest文件中声明服务：

然后，在Service类中创建计时器，并使用AlarmManager定期触发计时器：

class MyService : Service() {

    private lateinit var timer: CountDownTimer
    
    override fun onBind(intent: Intent): IBinder? {
        return null
    }

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        startTimer()
        return START_STICKY
    }

    override fun onDestroy() {
        super.onDestroy()
        stopTimer()
    }

    private fun startTimer() {
        val intervalMillis: Long = 1000 // 1 second
        val durationMillis: Long = 60000 // 1 minute
        
        timer = object : CountDownTimer(durationMillis, intervalMillis) {
            override fun onTick(millisUntilFinished: Long) {
                // update UI or whatever you want to do on each tick
            }

            override fun onFinish() {
                // stop service or whatever you want to do after timer ends
            }
        }

        timer.start()

        // set up alarm to trigger the timer
        val alarmManager: AlarmManager = getSystemService(Context.ALARM_SERVICE) as AlarmManager
        val pendingIntent: PendingIntent = PendingIntent.getService(
                this,
                0,
                Intent(this, MyService::class.java),
                PendingIntent.FLAG_UPDATE_CURRENT
        )

        val triggerAtMillis: Long = SystemClock.elapsedRealtime() + intervalMillis
        alarmManager.setExact(
                AlarmManager.ELAPSED_REALTIME_WAKEUP,
                triggerAtMillis,
                pendingIntent
        )
    }

    private fun stopTimer() {
        timer.cancel()
    }

}

最后，在应用程序中启动