Hey I am working in kotlin flow in android. I noti...

# android

[Vivek Modi]

Hey I am working in kotlin flow in android. I noticed that my kotlin flow collectLatest is calling twice and sometimes even more. I printed the log inside my collectLatest function it print the log.

[Vivek Modi]

https://stackoverflow.com/q/70748112/11560810

[Max Ferrier]

Mmmh, I'll try this :
The repeatOnLifeCycle will create a new coroutine when the lifecycle you gave in parameter is at least the state of your app. If you say Lifecycle.State.STARTED , you'll have a new coroutine for states STARTED and RESUME. So, I would try to remove it because you already have the launchWhenStarted juste above.

[Vivek Modi]

@Max Ferrier I removed repeatOnLifeCycle this but it didn't work

[Max Ferrier]

You mean you still have your 2 time or nothing ?

[Max Ferrier]

(And at the same time, according to the collectLatest's doc, it's normal to have 2 results.)

[Vivek Modi]

@Max Ferrier yes it calling 2 times

[Max Ferrier]

Normal. Everything works as it's written.
You have a first value at emptyList() and a second one with response.items .
In the doc, it says :

flow {
    emit(1)
    delay(50)
    emit(2)
}.collectLatest { value ->
    println("Collecting $value")
    delay(100) // Emulate work
    println("$value collected")
}

In the collect, the delay time is longer than in the flow. So if you send 20 values in your flow every 50ms, but your collect can treat only one value data in 100ms, you'll only work with the final value.
But if you send 20 values in your flow every 500ms, and your collect can still treat one value every 100ms, you'll work with the 20 values.

EDIT : With the first value wich finish the process and end the coroutine. If your coroutine is not killed, you'll work with the 20 values. In my link below, at the end of the first value, the GlobalScope is not kept alive.

[Vivek Modi]

@Max Ferrier thanks a million for great explanation Is there anyway to remove emptyList() and my collectLatest will call only once? Is it possible in flow?

[Max Ferrier]

https://pl.kotl.in/TjexxpjtF

[Max Ferrier]

@Vivek Modi: The main goal of the flow is to be triggered for every new data. You still can add a test on your list data.isNotEmpty()

[Vivek Modi]

okk great thanks