Anyone stumble across ViewModel death during language change?

When you create a custom LifecycleOwner, how do you define custom Events? There is ON_DESTROY event and I'd like to have ON_DESTROY_VIEW as well. P.S. Apparently there is a Fragment.viewLifecycleOwner.Lifecycle that does exactly this. Still curious about custom events, tho

The problem is I have not worked i n such a huge project before, so I think I will need some help with the Architecture of such an app. thanks in advance

how do I solve this?

Hi there. I have a question concerning

AAC MVVM

implementation. I have an activity with several

view models

, and I need to connect these. Currently I use

activity

as a kind of proxy between them. But that feels wrong. What would be the best way for one

view model

to observe events from other

view model

? Or is it completely wrong way of implementing

MVVM architecture

?

Why on earth use AAC ViewModel? Any profit?

is it ok if I specify a companion object in the shared fragment that contains this presenter, adn assign it from the using fragment when its ready?

Hi there. Consider the following scenario: I have a

Fragment

(A) that subscribes a

ViewModel

(V) in

OnActivityCreated()

. When opening this

Fragment

(A), I receive an update from

LiveData

. Then I open another

Fragment

(B), then get back to the first one (A). It gets inflated, and

onCreateView()

,

onViewCreated()

and

OnActivityCreated()

are called. We've just subscribed the

ViewModel

(V), but it does not emit any item (the most recent update). I'd expect a

LiveData

would behave like a

BehaviorSubject

in

RxJava2

(tell me if this comparison is appropriate), but there are no updates. What could go wrong? Any help would be appreciated.

how can i inject DataManager in my intent services , can any one help me ?

Does anybody have an opinion on multiple viewmodels being used in 1 view?

Since Activities/Fragments can be destroyed and recreated using the same ViewModel, does it make sense for us to create scoped Dagger components in our ViewModels? Would there be anything wrong with doing it that way?

Hi. I wanted to implement dynamic features with instant support in my app. It is almost working except di with dagger. in my app module i do not have access to my activity in the feature module. so i can not do the following in my dagger FragmentsModules.kt

@ContributesAndroidInjector(modules = [FooFragmentModule::class])
abstract fun bindFooFragment(): FooFragment -> FooFragment can not be accessed

Does someone have an solution for this issue? Slack Conversation

thats just wrapper around the binder connection listener

does anybody ever pass viewmodels into other viewmodels, or is it better to just inject multiple viewmodels into the common view

@ghedeon I believe it depends on your use case. In general LiveData is more simple and light weight abstraction than channels, but with much mire limited use case: observable hot property that works as RxJava BehaviorSubject or ConflatedBroadcastChannel. Also LiveData is always about delivery results on Main thread, but Channels provide much more in terms of passing messages between threads

Shared view model is a common pattern, when you use activity's VM in the fragment. What if the fragment itself has a viewmodel and they need to communicate? Do you link them on the fragment level, or you pass activity VM inside the fragment VM?

can I use MVVM without LiveData?

i create a viewmodel (1) for all those screens and it includes the 3 methods that each of them will invoke when it’s their turn

Hey, I'm trying to adopt clean architecture for an app for a college fest. There are three entities I need to handle, which I'm currently storing in Room db. I want to use Repository pattern, so I'm creating the Repository interface to be implemented by the three. 1. Should I mark

getAll

as

suspend

? As currently it isn't required due to Room (Using LiveData<List>), but may be required if/when some other source of data is added? 2. Should the code to fetch data from server and populate Room's db be written in the Repository?

should the data source operate by implementing interfaces defined in the repository

Hey guys, I’m using MVVM in a project (for learning purposes mainly) and I’ve implemented a few Fragments with a ViewModel and an Adapter in Java, and haven’t had problems, but this is the first one I’ve written in Kotlin, and for some reason when I delete an item from the cart, I don’t get a notification in the ViewModel Observer and hence I don’t clear the adapter items. Any ideas why this might be happening?

I feel like it warrants its own package, but its not a ui facing feature like news or weather, where should I put it? account/ package in root? in data/? if root, then data/ already has MessageRepository etc, wouldnt that be a mismatch?

Do you guys adapted Netflix’s componentization?

Assuming that we have a single Activity app with an architecture that delivers all the exceptions to the presentation layer. Actually I got an interface

AndroidComponent

that will be implemented by `Activity`es, `Fragment`s, `Worker`s/`Service`s ( and basically nothing else ) that provides a reference to

Notifier

.

Notifier

jobs are 1 inform

Timber

( that will eventually inform

Crashlytics

) and 2 show a message to the user. Actually the message to the user is delivered through an abstraction of

Toast

injected in the constructor; but I would like to use a

SnackBar

instead, if the app is in foreground: so I was thinking about a

SnackBarManager

( fantasy name 😁 ) that will be implemented by the

Activity

which will pass the set/remove the interface to

Notifier

(

onStart()' /' onStop()

) , so the Notifier could call

snackBarManager?.let { it.showSomething() } ?: showToast()

What do you think about that? 🙂

hm I wonder if okhttp Authenticator can even handle such case, afaik the return value is request to retry, and null to pass 401 downstream

how come? arent foreground services cool anymore to not have the process killed?

Do you use

Router/Navigator

pattern in your apps? If yes, do you inject it into the ViewModel or activity? I've been using it for a while, for the sake of SRP and stuff.. but honestly it's tightly coupled with activity/fragment anyways (context, animations, fragmentManager, etc) so I hardly see any benefit of another abstraction.

when starting a screen for example, inside onCreate and you’re hooking up things to do this call, is this how it would go?

leaseCarsVM.getLeaseCarsResult().observe(this, getLeaseCarsObserver)
        leaseCarsVM.getLeaseCars(true)

        swiperefreshLayout.setOnRefreshListener {
            leaseCarsVM.getLeaseCarsResult().observe(this, getLeaseCarsObserver)
            leaseCarsVM.getLeaseCars()
        }

try moving it to say the beginning of the screen, all of them together hooked up to the various other observers, and then make the VM calls later, they don’t come back successfully, has to be before the call..

For quite a while I was using the wrapper around the string resource. In order to delay context involvement. Ex: you have a string int, plus some params for the format, but you're not ready to pull the actual value, because it requires the context. So you delay it with a wrapper.

class StringResource private constructor(
    val string: String?,
    @StringRes val stringRes: Int?,
    vararg val args: Any?
) {
    constructor(@StringRes stringRes: Int, vararg args: Any? = emptyArray()) : this(null, stringRes, args)

    constructor(string: String) : this(string, null, null)

    fun resolve(context: Context): String =
        if (stringRes != null) {
            context.getString(stringRes, args)
        } else requireNotNull(string)

  }
=============
Usage: 
ViewModel: StringResource(R.string.foo, arg1, arg2)
View: stringResource.resolve(context)

I'm wondering if other people do something similar and how their wrapper looks like.

should this mapping be just thrown in FooRepository or should the be some wrapper around retrofitApi interface?