how to avoid using GlobalScope-CodePudding

In my code, I have a time-out functionality and I want to use a countdown timer but after a lot of research, I couldn't find similar functionality as a countdown timer in Kotlin coroutine (able to start, cancel and catch finish callback). Then I decided to use GlobalScope.launch. I know this is a bad solution but my code is working perfectly.

Here is my code

viewModelScope.launch {
            val timer = object: CountDownTimer(Constants.PAYMENT_TIMER, 1000) {
                override fun onTick(millisUntilFinished: Long) {}

                override fun onFinish() {
                    GlobalScope.launch {
                        _eventFlow.emit(UIPaymentEvent.NavigateToBack)
                    }
                }
            }
            timer.start()
            collectPaymentIntentUseCase.invoke(currentPaymentIntent!!).onEach { result ->
               
                when (result) {
                    is Resource.Success -> {
                        timer.cancel()
                        if (result.data?.exception == null) {

My question is how can find a 100% similar function to avoid using GlobalScope but be able to use the countdown timer (start, cancel,onComplete callback)?

Note: I am using GlobalScope.lanch to be able to emit UIPaymentEvent.NavigateToBack event to my view

CodePudding user response：

Your question is somewhat unclear, please try to add more details what actually are you trying to achieve and what is the error you are facing.

CodePudding user response：

You don't need a CountDownTimer here. Just use the delay() suspend function.

viewModelScope.launch {
    val job = launch {
        delay(Constants.PAYMENT_TIMER) // Wait for timeout
        _eventFlow.emit(UIPaymentEvent.NavigateToBack)
    }        
    collectPaymentIntentUseCase.invoke(currentPaymentIntent!!).onEach { result ->           
        when (result) {
            is Resource.Success -> {
                job.cancel() // Cancel the timer
                if (result.data?.exception == null) {

CodePudding user response：

You can use callbackFlow for listen your timer. I just code this editor. I hope it will be helpful.

fun timerFlow() = callbackFlow<UIPaymentEvent> {
    val timer = object : CountDownTimer(10, 1000) {
        override fun onTick(millisUntilFinished: Long) {}

        override fun onFinish() {
            CoroutineScope().launch {
                _eventFlow.emit(UIPaymentEvent.NavigateToBack)
            }
        }
    }
    timer.start()
    awaitClose()
}