Timer based on Handler stops, Android, Kotlin-CodePudding

I use Handler for creating a timer in a Widget. I use the recommended constructor, i.e. passing a Looper to it.

    private val updateHandler = Handler(Looper.getMainLooper())

    @RequiresApi(Build.VERSION_CODES.Q)
    private val runnable = Runnable {
        updateDisplay()
    }

    @RequiresApi(Build.VERSION_CODES.Q)
    private fun updateDisplay () {
        updateHandler?.postDelayed(runnable, TIMER_MS)
        // some other code
    }

The TIMER MS is set to 3000 ms. The timer runs fine for a while and execute the given code. However after a random time elapsed the timer stops working and no more execution of the given code happens.

Please advise what the problem could be ond how to fix it. Alternatively, can I use some other timer? (The timer should go off every few second - this is the reason why I use Handler)

Thank you for any advice in advance

CodePudding user response：

You could always try using a Coroutine for something like this:

class TimedRepeater(var delayMs: Long,
                    var worker: (() -> Unit)) {
    private var timerJob: Job? = null
    
    suspend fun start() {
        if (timerJob != null) throw IllegalStateException()
        timerJob = launch {
            while(isActive) {
                delay(delayMs)
                worker()
            }
        }
    }
    suspend fun stop() {
        if (timerJob == null) return
        timerJob.cancelAndJoin()
        timerJob = null
    }
}

suspend fun myStuff() {
    val timer = Timer(1000) {
        // Do my work
    }
    timer.start()
    // Some time later
    timer.stop()
}

I haven't tested the above, but it should work well enough.

CodePudding user response：

You can use CountDownTimer from Android framework to achieve the same. It internally uses Handler for timer

val timer = object: CountDownTimer(1000,1000){
    override fun onTick(millisUntilFinished: Long) {
         
    }

    override fun onFinish() {
    }
}
timer.start()