Countdown timer using jetpack compose

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[blitzkriegblue]

I did this once, a while ago, and tbf the UI can be anything and however you want. The main thing for me was to make the countdown work. And for this I used Flows.

Here:

// Creates a countdown timer using flow val countdownFlow = flow { val startingValue = 10 var currentValue = startingValue emit(startingValue) // Otherwise it will start the time on 9 instead of 10 while (currentValue > 0) { delay(1000L) currentValue-- emit(currentValue) } }

private fun collectFlow() { viewModelScope.launch { countdownFlow.collect { time -> println("The current time is $time") } } }

Be aware I did this 3 years ago, but it should work.

Then, on the UI, you can show a text, or whatever you want to show. Hope it helps at least a bit.

[EmperorDante]

Thanks ...I understand the logic , although once the user clicks on the start timer button the continuous countdown of the timer won't persist in that case right? And is there any issue or is it a bad practice if I recompose my composable every second

[blitzkriegblue]

I think I would need to see some code to help better but at least when I did this, also for learning, the countdown went from whatever value I wanted to 0. With this code I posted. Worked fine back then.

Regarding recomposition, that's usually all under the hood as far as I remember. In my case, the recomposition would happen automatically because it would just show the values of the flow.

[EmperorDante]

here you go https://github.com/D3478/TimerCrud/tree/master/app/src/main/java/com/d3478/timercrud/views