can I use MVVM without LiveData

Question

Sinan Kozak · Answer

Yes

oday · Answer

why not < commanderpepper>

Sinan Kozak · Answer

LiveData is just a data type which also let you observe with lifecycleowner So it should be okey to use it without VM

oday · Answer

yes makes sense

commanderpepper · Answer

I gave a thumbs down because I don t like single word responses I m not a fan of Yes or No

oday · Answer

so you are a fan of a single reaction emoji

oday · Answer

slightly smiling face

oday · Answer

you literally did the same as him

oday · Answer

lol

Sinan Kozak · Answer

I start with Yes to ensure you it is not a stupid question

oday · Answer

im aware

commanderpepper · Answer

Yeah you re right I didn t let him respond with greater detail I m sorry for the hasty emoji response

oday · Answer

its daunting to follow a damn tutorial video 80 episdoes on how to do clean arch

oday · Answer

what s this about presenters AND viewmodels in the same arch

Michael Bernier · Answer

You could use RxJava or nothing but it depends if you go full on with ViewModel from Android Architecture component or your own implementation In all cases for MVVM to work you need to use the Observer design pattern

oday · Answer

from google s own intro to ViewModels video

oday · Answer

i do use Rx

oday · Answer

the point here is easy testing and to do that I ve found that i am slowly converging towards VM

oday · Answer

because i started with the test the rest is having to adhere to the same structure kind of

oday · Answer

ohh ok ok so the viewmodel is literally all the view stuff that used to sit inside the activity

oday · Answer

now the activity just reads like a set of instructions

oday · Answer

presenters hand off to repository for calls give back to viewmodel for display change

oday · Answer

activity just orchestrates

Michael Bernier · Answer

pretty much I just don t use presenters with VM i put all the logic in the repository for now

oday · Answer

hmm

oday · Answer

yea same same

oday · Answer

useless to have a presenter

oday · Answer

because if you write a test for example to test the presenter

oday · Answer

all you ll be doing is making sure the call went out to the repo

oday · Answer

which is useless

Michael Bernier · Answer

pretty much

oday · Answer

ok good

oday · Answer

glad i went and asked what a viewmodel was stuck out tongue

oday · Answer

do you use LiveData

Michael Bernier · Answer

yes I do

ghedeon · Answer

if you already use RX LiveData won t give you much Although I d still consider replacing your rx code in Views with LD Because it s a bit more handy there Also if you want to move to channels from RX in the feature you ll have less work to do

oday · Answer

I don t have any Rx code in views

oday · Answer

all my Rx only is for threading basically

oday · Answer

you could take out the entirety of what I use Rx for and put coroutines

oday · Answer

just to be able to say request wait receive call view with result

oday · Answer

so I made like an observableuseCase class that does this for me and now each endpoint call is a subclass of it

oday · Answer

or a completableusecase

ghedeon · Answer

than it s an easy question I d NEVER use LiveData below presenters ViewModels etc slightly smiling face

ghedeon · Answer

coroutines won t replace your reactive code tho Only Maybe Single and Completable

oday · Answer

you mean in my use case you d never use live data given the way ive got things set up

oday · Answer

i mean cause it is reactive what they re preaching im already doing

oday · Answer

couldn t get the shtick

oday · Answer

cause it s already like that

ghedeon · Answer

assuming we re below presentation layer ie data amp domain The decision tree is the following is my code reactive If not returns `T` `Maybe lt T gt ` `Single lt T gt ` `Completable` just coroutines enough If yes returns stream of `T` then either Rx or Channels LiveData will work as well but it s like shooting yourself in the leg Because the next minute you move to LD you ll want some operators and it has none of them

ghedeon · Answer

you re doomed to reinvent the wheel and write all by yourself

ghedeon · Answer

the `map` kotlin extension was added in alpha version of ktx livedata library recently It`s like RxJava 0 0 0 alpha there was an attempt 1 version

oday · Answer

wow

oday · Answer

yea I didnt know that

oday · Answer

map and filter are extremely essential to the results

oday · Answer

and a host of others

oday · Answer

ok thanks a lot

oday · Answer

if you re still there < ghedeon> since I am not using LiveData I have nowhere to post back from inside the viewmodel do I just let it make the call to my endpoint method returns Observable I can then pass the viewmodel to the presenter which makes the call there and passes back to the view

oday · Answer

ahh no the viewmodel is going to be like the activity i just move the shit there

oday · Answer

I dont know

oday · Answer

do I just again give it a reference to my view interface which my activity implements

oday · Answer

that don t sound right

Michael Bernier · Answer

your activity only subcribes to changes

Michael Bernier · Answer

your viewmodel doesn t know about the activity

Michael Bernier · Answer

your xml use data binding to display data

Michael Bernier · Answer

it can also listen to LiveData directly

Michael Bernier · Answer

coroutine can replace threading in Rx

Michael Bernier · Answer

kotlin already has transforms that can replace most rx transform

oday · Answer

given this though without wanting to change anything <https pastebin com MBF2Ujuy>

oday · Answer

how can I do it have the data return back to the activity where it s displayed

oday · Answer

I can wrap it in another observable

Smorg · Answer

Quick question why would you need a presenter and a viewmodel for an activity feature are they not meant to perform the same function with a slightly different implementation You can still have all the logic in the viewmodel and do the normal command subscription in your activity fragment

oday · Answer

yes yes just my confusion

oday · Answer

you can do LiveData without having to do databinding and XML shit

Smorg · Answer

trust me databinding is dope try it and thank me later

oday · Answer

i cannot imagine going into an XML file and seeing something that has to do with non graphical things

oday · Answer

my only barrier

Smorg · Answer

your activities fragments will have the kind of leanness you have never seen before when you use it

oday · Answer

i guess though

oday · Answer

if you switch out where you want your data to end up you just carry a tag with the XML view and now that new view will host your data

oday · Answer

one step at atime

ursus · Answer

yes use rx