And the other way round, a `LiveData` as `Flow`: `...

# android

[Marc Knaup]

And the other way round, a LiveData as `Flow`:

@UseExperimental(ExperimentalCoroutinesApi::class)
fun <Value> LiveData<Value>.asFlow() = channelFlow<Value> {
	val observer = Observer(this::offer)
	observeForever(observer)
	awaitClose { removeObserver(observer) }
}

[Dominaezzz]

Instead of launch and send, consider using offer.

[Marc Knaup]

Great thanks, updated 🙂

[Dominaezzz]

Also, you have to call awaitClose after observeForever. Otherwise the observer will be registered after the Flow closes/completes.

[Marc Knaup]

oh right, it will suspend there 😮
updated 🙂

[Adam Powell]

Basically yes. More or less that is pending a future -ktx artifact release in androidx 🙂

[louiscad]

Also, you probably want to use conflate().

[Marc Knaup]

Hmm, `LiveData`’s emit() suspends until the value has actually been set.
If I use conflate() for the other way round with Flow the behavior would be different, wouldn’t it?

[Marc Knaup]

I guess it’s already a problem because channelFlow is already buffered 🤔

[Marc Knaup]

Nevermind, I mixed it up. This is about getting a value out of LiveData, not into it 🙄

[Marc Knaup]

As I can’t edit the original message anymore here the updated version:

@UseExperimental(ExperimentalCoroutinesApi::class)
fun <Value> LiveData<Value>.asFlow() = channelFlow<Value> {
    val observer = Observer(this::offer)
    observeForever(observer)
    awaitClose { removeObserver(observer) }
}.conflate()