Hey guys! I'm using Flow to emit data from Repositories all the way up to Viewmodels. I've watched some talks at Dev Summit and now it's suggested to switch to LiveData to expose data to activities views. My question is: is it really necessary and what are the differences between exposing as LiveData or collecting values directly from Flow in view's lifecycleScope?

You dont have to use LiveData. But there benefits to using livedata. Livedata builder is pretty powerful and has built in coroutines support . And it can become lifecycle aware, so you dont have to worry about managing the lifecycle so you dont have to worry about managing the coroutine lifecycle on your own

Usually when Google devs recommend something it is best to ignore them and do the exact opposite.

Most of the api you develop with are made by Google devs. The thing is you can use LiveData with flow or coroutines. It doesnt have to be one or the other. Depends on your actual usecase. You can also achieve the same thing with flow or callback flow by itself. But you will handle lifecycle on your own.

Most of the APIs I use are terrible. I can count on one hand the Android SDK classes that aren't crap. In fact LiveData and ViewModel exist only to work around other terrible design decisions of the Android API in the past. If you already use Flow or Rx then there's no point to LiveData. It does pretty much the same thing but worse. It's only useful for people who never adopted either and are for some reason stuck to whatever is endorsed by Google.

I think its just a matter of opinion. For me there is benefits to live data. One it works seamlessly with data-binding, and life-cycle owner.

Yeah, thanks guys. Right now both are lifecycle aware (LiveData with lifecycleowner and Flow with lifecycleScope). @yigit was talking about "caching behaviour" embedded in LiveData, that's why I wanted to know more about it.

Ahh I see. So for LiveData value is only queried when there is a active observer if not it will be cached until it become reactive. So that means if you use your fragment , or activity as its lifecycle owner, it will only emit while your active or fragment is in some kind of active state, if not it will just cache the last value you set

So, the real question is how to make Flow behave like LiveData (some

cache

operator?), so you can finally ditch and forget LiveData, like we usually do with google stuff 🙂?

Here comes the hate train lol. Live data and Flow, are fundamentally different and can work in parallel . there was a whole google talk about using Flow with LiveData...

Yeah, critical thinking is called "hate" nowadays :). Thankfully, it's not a VICE comment section, lol. That talk makes sense, because it's logical for Google to talk about their libraries. That explains nothing.

LiveData

,

Flow

,

RxJava

are fundamentally the same thing — Observable. How do I know? Well, Rx was used instead of LiveData for years. Where is Google's recommendation to use LiveData in Repositories now? Why Room supports Flow and Rx and before it was LiveData? Why SqlDelight supposrts Flow and Rx? It's so fundamentally different that it's interchangeable in the bat of an eye? 🙂 What a paradox.

Bruh , they are fundamentally different. I feel like I tell you this all the time. LiveData, is a data holder. Nothing more nothing less. Flow fundamentally was ment to handle cold streams of data , which is opposite of channels that handle hot streams of data. Rx was both cold and hot . Like you can actually use all these technologies in parallel if you really wanted to. Ahh so what if Room supported those types , it also supported Deferred<T> to. Will you now say Deferred and Flow are the same thing now lol. The only similarity is they can hold data, but the way data is transmitted is completely different for each. There are things that livedata shines at. Being that appcompact activity and fragment now extend lifecycle owner, livedata can integrate with the android lifecycle right out of the box. Since it was built to work with it. And it works better with databinding.Sure you can achieve the same thing with flow but not right out the box, there are some considerations that have to be made. If you want to use livedata in your repos you can, you just have to use Transformations.. But it wasnt built for asynchronous operations that's why they integrated it with coroutines, so it makes sense to use flow or suspend in the repo level since you normally do asynchronous stuff in the repo level... Its ok to be a anti google protester, but atleast give a fair assertion about there APIs lol.

@rkeazor I agree 💯 with what you are saying , I don't understand why people are torturing themselves though, if you feel things you work with suck (Andoroid apis) just move on to something that will bring you pleasure. What is the point of saying I hate Andoroid sdk and work with it everyday. Or if you don't hate it as much...just stop seeking attention with this loud statements (I do the opposite of what Google says etc) We use livedata + databinding in the presentation layer (viewmodel -> view ) and it works best and for handling streams and async operations use coroutines why do you want to pick one and then complain how Android sucks that you struggle every day with your choices of architecture and do the opposite of what Google offers you as a solution to your problem 🤷🤷🤷 and using livedata with room is actually pretty handy if you don't require data transformations, when I just need to observe the changes out of the box it is great to return a livedata and just write the changes and they are gonna be applied to UI automatically, I designed two apps with this set up already and it had been a breeze so far