kotlinlang #koin

Hi everybody, I am trying to find a good solution for a following use case without overengineering it: I have generic stuff, that is currently sitting in the root scope. I also have user session-related stuff, which is currently in

SCOPE_USER

. This scope is created when user logs in and I close it on logout. There is a custom

by injectUser()

function to inject things from this scope for convenience. Question: is it possible to link

SCOPE_USER

to root when it is created and close it when user logs out? Or should I rather create another

SCOPE_GENERAL

for all the stuff, that is currently in root and then link

SCOPE_USER

to it? This would require to inject from a scope -> custom

by injectGeneric()

function. Ideally linking stuff to root scope would be ideal, but I do no see a way to do it. Or should I rather keep things as they are? Many thanks for any ideas in advance!

Florian Eula

10/26/2020, 8:59 AM

Is there a known source of crashes from the 2.2 RC where the savedstatehandle would not be passed properly ? My module declares a viewmodel as such:

viewModel { ThingyVM(handle = get(), ...) }

When injecting it in my fragment, I properly use

override val viewModel: ThingyVM by viewModel(state = { arguments ?: bundleOf() })

Sometimes, maybe like one launch out of 30, I get a crash,

Caused by: org.koin.core.error.NoBeanDefFoundException: No definition found for class:'androidx.lifecycle.SavedStateHandle'. Check your definitions!
        at org.koin.core.scope.Scope.throwDefinitionNotFound(Scope.kt:277)

Patrik Åkerfeldt

10/29/2020, 12:56 PM

I'm new to Koin so hopefully I'm just doing something stupid. I have a working Ktor backend service running with Koin but I'm trying to add tests. As soon as I add the dependency

<dependency>
            <groupId>org.koin</groupId>
            <artifactId>koin-test</artifactId>
            <version>2.2.0-beta-1</version>
            <scope>test</scope>
        </dependency>

I fail to even start the service with error:

Kotlin: Cannot access class 'org.koin.core.scope.ScopeInstance'. Check your module classpath for missing or conflicting dependencies

in all places where I use

org.koin.ktor.ext.inject

aipok

10/29/2020, 2:07 PM

Trying to integrate 2.2.0-beta-3 into my project and interesting if activity is subclass of

ScopeActivity

and has field defined like this

private val splashVM by scope.viewModel<SplashViewModel>()

it failed with

Caused by: java.lang.IllegalStateException: Your activity is not yet attached to the Application instance. You can't request ViewModel before onCreate call.

Am I understand incorrectly that

by scope.viewModel

should be called only while I’m calling

splashVM

somewhere later in my code? And I only calling

splashVM

inside

onCreate

but for some reason it still failed and seems to call scope right away on activity init method call. @arnaud.giuliani should I use it somehow differently now?

gps

11/16/2020, 7:23 AM

Hi everyone, I'm using Koin with Ktor, and previously I was using Koin in various classes by implementing the

KoinComponent

interface, and then using

inject

. I don't need to do this if I'm using it in the context of a route, or application, but I think I do need to do this if I'm using it my own classes? After upgrading to Koin 2.2.0 however, I'm getting a warning asking me to add an annotation:

KoinApiExtension

. This suggests to me that I'm likely doing something stupid here. Why is it a bad idea for me to implement

KoinComponent

? Thanks!

Archie

11/18/2020, 9:19 AM

Hi @arnaud.giuliani, my I ask a question. I found this in the documentation:

class Presenter(val view : MyViewContract)

val androidModule = module {

    scope<MyActivity> {
        // inject current MyActivity
        scoped { Presenter(get()) }
    }
}

since the

activityScope()

is backed inside the

ViewModel

// Create Activity scope (backed by ViewModel)
override val scope: Scope by lazy { activityScope() }

And the presenter have the reference of the

View

wouldn't this leak the

Activity

? If I understand it correctly, since the

scope

is backed inside a

ViewModel

the same instance of

Presenter

will be provided when the

Activity

did some configuration changes (such as device rotation)... The Activity will be destroyed with its views and a new Activity will be created but.. the presenter is still holding the instance of the destroyed view (View of the Old Activity)... I am really confuse.

Moritz Post

11/18/2020, 10:19 AM

at the moment i am doing:

@Composable
  private fun configureNavigation() {
    val navController = rememberNavController()
    loadKoinModules(module { single<NavController> { navController } })
  }

This has the disadvantage that i have to actively unload the module when the Activity is destroyed.

arnaud.giuliani

11/18/2020, 1:26 PM

Don’t use scopes if you don’t really need it. It’s a dagger thing to put scopes everywhere 🙂

😀 1

arnaud.giuliani

11/19/2020, 8:41 AM

So many topics around 🙂 if there is some people with experience that want to help, feel free to ping me 👍 I’ve just started some experiments

holgerbrandl

11/22/2020, 5:46 PM

What would be an idiomatic way to pass an Integer via injection using koin? I want to use/inject a counter in different components. I know that a direct pass by ref is not possible (https://stackoverflow.com/questions/51638871/pass-an-integer-by-reference-in-kotlin)

pawegio

11/25/2020, 2:17 PM

Hi, after updating koin from 2.1.5 to 2.2.1, I’m no longer able to mock

MyViewModel

in android Robolectric UI tests:

@get:Rule
val koinTestRule = KoinTestRule.create {
    androidContext(testApplication)
    modules(listOf(
        /* modules */,
        module { viewModel(override = true) { mock<MyViewModel> { /* ... */ } },
    ))
}

I use all-open plugin to open view model class for testing purpose (to perform stubbing):

@AllOpenAnnotation
class MyViewModel(
   /* ... */
) : ViewModel()

It throws following exception when fragment scenario launches:

java.lang.NullPointerException
	at androidx.lifecycle.ViewModel.setTagIfAbsent(ViewModel.java:157)
	at androidx.lifecycle.AbstractSavedStateViewModelFactory.create(AbstractSavedStateViewModelFactory.java:70)
	at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:185)
	at androidx.lifecycle.ViewModelProvider.get(ViewModelProvider.java:150)
	at org.koin.androidx.viewmodel.ViewModelResolverKt.get(ViewModelResolver.kt:23)
	at org.koin.androidx.viewmodel.ViewModelResolverKt.resolveInstance(ViewModelResolver.kt:12)
	at org.koin.androidx.viewmodel.scope.ScopeExtKt.getViewModel(ScopeExt.kt:86)
	at org.koin.androidx.viewmodel.scope.ScopeExtKt.getViewModel(ScopeExt.kt:72)
	at org.koin.androidx.viewmodel.koin.KoinExtKt.getViewModel(KoinExt.kt:41)
	at org.koin.androidx.viewmodel.ext.android.FragmentExtKt.getViewModel(FragmentExt.kt:71)
	at com.xyz.XYZFragment$$special$$inlined$sharedViewModel$2.invoke(SharedViewModelExt.kt:79)
	at kotlin.UnsafeLazyImpl.getValue(Lazy.kt:81)
	at com.xyz.XYZFragment.getViewModel(XYZFragment.kt)

any tips?

oday

11/30/2020, 10:41 AM

I guess if I were to provide a getter for this object, the value I’d return is just the name of the object again

deviant

11/30/2020, 12:06 PM

hey guys, i have to definitions in my module:

factory<() -> User>

factory<() -> Location>

koin treat it as same type and failed with this exception:

org.koin.core.error.DefinitionOverrideException: Definition '[Factory:'kotlin.jvm.functions.Function0']' try to override existing definition. Please use override option to fix it

are there any workarounds?

Mark

12/04/2020, 3:39 AM

Any thoughts about using App Startup library to initialize Koin (instead of Application subclass)? https://proandroiddev.com/app-startup-under-the-hood-with-koin-library-example-380e188568ad

Mark

12/05/2020, 10:29 AM

How to properly set up and close a

CoroutineScope

for a Koin

Scope

holgerbrandl

12/05/2020, 7:11 PM

Hi, is it possible to resolve generic types with koin? I've tried with

import org.koin.core.KoinComponent
import org.koin.core.context.startKoin
import org.koin.dsl.module

class State<T>(val initialValue: T, name: String? = null)

fun main() {
    val sim = module(createdAtStart = true) {

        single{ State("red") }
        single{ State(false) }
    }

    startKoin() { modules(sim) }

    val koin = (object : KoinComponent {}).getKoin()
    val boolState = koin.get<State<Boolean>>()
    val stringState = koin.get<State<Boolean>>()
}

but this fails with

Exception in thread "main" org.koin.core.error.DefinitionOverrideException: Definition '[Single:'State']' try to override existing definition. Please use override option or check for definition '[Single:'State']'

kenkyee

12/05/2020, 9:35 PM

You're better off doing something like: Class Blah : State<Red> Then Single { Blah() }

👍 1

Joaquim Ley

12/07/2020, 2:48 PM

I’m not able to use Koin in a KMM project 😞 really need some help: This is the Koin in the shared module

fun initKoin(appDeclaration: KoinAppDeclaration = {}): KoinApplication {
  return startKoin {
    appDeclaration()
    modules(domainModule, remoteModule, dataModule)
  }
}

fun startIosKoin(iosModules: List<Module> = emptyList()) = initKoin {
  modules(iosModules)
}

Which is called by KoiniOS.kt

private val iosModules: List<Module> = listOf(
  storageModule
)

fun inject() = startIosKoin(iosModules)

This

storageModule

has iOS specific objects such as

NSDefaults

Ths domain module has simple kotlin objects as well data module (repository layer) and the remote module is ktor where I have

expect/actual

engines. (which is called in the AppDelegate

KoiniOSKt.inject()

) - But for some reason whenever I try to use any use case on iOS it just breaks no

NoBeanDefFoundException#<init>(kotlin.String){

Android works fine but iOS can’t use any of the deps, is there something obvious that I am missing or do I need to post more code/plumbing?

Saul Wiggin

12/15/2020, 3:29 PM

Still stuck on getting Koin working

KoinApplication has not been started

deviant

12/16/2020, 12:18 PM

guys, are there any helpers to utilize NavArgs from androidx navigation lib? something similar to SavedStateHandle? pass args to viewmodel? maybe SavedStateHandle to NavArgs converter? something like this

timrijckaert

12/16/2020, 4:58 PM

Where can I find the most up to date sample which demonstrates Koin in all its glory in an Android app. The official one https://github.com/InsertKoinIO/koin-samples seems a bit out dated 😅

Yasutaka Kawamoto

12/25/2020, 2:58 AM

Module#isLoaded is now INTERNAL in 2.2.0, but I want to refer to isLoaded, is there an alternative way? https://github.com/InsertKoinIO/koin/blob/master/CHANGELOG.md#220-beta-2

👍 2

bobby

12/29/2020, 1:47 AM

Hi there, I want to ask a question, is there’s a way to catch an exception that happen during creation of an object inside

single{}

? The reason I’m asking this is because when creating

EncryptedSharedPreferences

object using

single{}

, sometimes it’s throw an Exception, and I want to catch that, prevent the crash app on user side, thanks

Philipp Mayer

12/30/2020, 12:50 PM

Hello everyone, I'd like to ask a question: I currently start using Koin on the Backend with Ktor, and have the following situation:

fun Application.rooms(db: DB) {
    install(Koin) {
        modules(roomsDI)
    }

    val roomFooBar: RoomFooBar by inject()

    routing {
        roomRoutes(roomFooBar)
    }
}

val roomsDI = module {
    single<RoomFooBar> { RoomService(get()) }
    single<RoomRepository> { RoomDatabaseAccessor(???)}
}

class RoomDatabaseAccessor(private val db: DB) : RoomRepository {...}

I'm not sure how to pass the

db

parameter (which is a function parameter of

Application.rooms()

) into the koin module. The parameter changes depending on the context, so just declaring it inside the

module { }

would not work. Any hints for that? I could not really find a satisfying solution in the docs. Thanks a lot!

timrijckaert

01/03/2021, 9:45 AM

https://stackoverflow.com/q/65439079/2976366 It would be nice if someone could give a solution to this since it is such a common question and architecture used in Android

➕ 2

nrobi

01/05/2021, 11:24 AM

Could anyone pinpoint to a working

KoinTestRule

example? I’m trying to use

KoinTestRule.create{ }

then

koinTestRule.koin.loadModules()

to override some bean definitions with mocks, though I’m bumping into:

java.lang.IllegalStateException: A KoinContext is already started

holgerbrandl

01/05/2021, 9:08 PM

Hi there, is it possible to list/iterate all declared instances of a koin instance?

tieskedh

01/08/2021, 11:50 PM

Noob question: I am refactoring a single app that is build for multiple organisations. An organisation has various rules.and based upon those rules decisions are made. At this moment a reference to the organisation is passed around almost everywhere. This means that if a new piece of data needs to be passed around, it's very easy to add it to the organisation, which therefor is huge. I read about koin scopes and now is my question: is it possible to use scopes to create classes based upon the current organisation-ID?

Kshitij Patil

01/16/2021, 2:56 PM

How to provide android context to

checkModules()

test ? I'm getting can't provide null context to Database object as my viewmodel depends on repository which depends on room database. I tried to follow androidx-samples example from repo but failed to get it working

Helio

01/19/2021, 7:04 AM

Hello, 👋🏽 I was wondering if this would still be a good manner to inject dependencies using Koin in Top level function. https://stackoverflow.com/a/50840374 Does anyone have a better approach for it?

Title

Helio

01/19/2021, 7:04 AM

tynn

01/19/2021, 9:09 AM

I don't think so. Eventually you should create a single instance within your Koin graph instead of using top level functions which require dependencies.

Helio

01/19/2021, 9:14 AM

What do you mean is: Wrap up this "top level function" in a class and probably inherit from KoinComponent to allow the injection of the class I want?

arnaud.giuliani

01/19/2021, 10:26 AM

You can use directly the global context:

GlobalContext.get().get()

in next Koin version, it will be more

defaultContext().get()

tynn

01/19/2021, 10:57 AM

@Helio I acutally meant to use a class with dependencies.

KoinComponent

should not be necessary then.

arnaud.giuliani

01/19/2021, 10:59 AM

yep 👍

Helio

01/19/2021, 10:04 PM

Hello again, First of all, I would like to thank you both for your quick response. 🙂 • We are currently using Koin 2.2.2 for Ktor. I ended up going with the GlobalContext as suggested by Arnaud, I will try to explain why, even though it might sound confusing (I know how these things are.. haha). Also, it worth saying that we will keep watching for updates. to get rid of the second

get()

. @tynn, in our scenario, we have a Ktor Controller (which is used to declare our apis) and for this specific case we have this “Helper” class, which handle some Generic Top Level functions for us. For example, in our Controller, we have the following

snippet

. There you can see that we are injecting a UseCase class.

fun Route.tokenApi() {
    val createAccessTokenUseCase: CreateAccessTokenUseCase by inject()

    route("/token") {
        post("/build") {
            val buildInfo = call.principal<Principal>().getBuildInfo()
            createAccessTokenUseCase.createBuildToken(buildInfo,
                    TokenatorPermissionGroupProvider.getGroupsFor(call.request.local.uri)).let { call.respond(HttpStatusCode.Created, it) }
        }
}

This line

val buildInfo = call.principal<Principal>().getBuildInfo()

reference our Top level function

getBuildInfo()

. This function will use different classes depending on the

Principal

. The way I was doing before, I was injecting the class I wanted in the Controller context and passing it to my function like this

getBuildInfo(injectedClassForPrincipal1)

. Complete example:

fun Route.tokenApi() {
    val createAccessTokenUseCase: CreateAccessTokenUseCase by inject()
    val myInjectedClassForPrincipalOne: MyInjectedClassForPrincipalOne by inject()
    route("/token") {
        post("/build") {
            val buildInfo = call.principal<Principal>().getBuildInfo(myInjectedClassForPrincipalOne)
            createAccessTokenUseCase.createBuildToken(buildInfo,
                    TokenatorPermissionGroupProvider.getGroupsFor(call.request.local.uri)).let { call.respond(HttpStatusCode.Created, it) }
        }
}

Soon, we will need to make

getBuildInfo()

able to handle a request for a different principal… Which we would need to add another parameter to

getBuildInfo(injectedClassForPrincipal1, injectedClassForPrincipal2)

. Complete example:

fun Route.tokenApi() {
    val createAccessTokenUseCase: CreateAccessTokenUseCase by inject()
    val myInjectedClassForPrincipalOne: MyInjectedClassForPrincipalOne by inject()
    val myInjectedClassForPrincipalTwo: MyInjectedClassForPrincipalTwo by inject()
    route("/token") {
        post("/build") {
            val buildInfo = call.principal<Principal>().getBuildInfo(myInjectedClassForPrincipalOne, myInjectedClassForPrincipalTwo)
            createAccessTokenUseCase.createBuildToken(buildInfo,
                    TokenatorPermissionGroupProvider.getGroupsFor(call.request.local.uri)).let { call.respond(HttpStatusCode.Created, it) }
        }
}

Using the GlobalContext.get().get(), doesn’t make necessary for me to be injecting class by class. I can just reference them in the Top level functions it should be used. Also, IMHO, I don’t think for this scenario it makes sense to let my TokenController knows about (myInjectedClassForPrincipalOne, myInjectedClassForPrincipalTwo). Please, let me know if you think it makes sense or if it doesn’t make sense at all (I’m relative new to Kotlin). Also, I’m always keen to hear different point of views.

arnaud.giuliani

01/20/2021, 5:08 PM

yes a bit like compose, it can be a scenario to just inject somewhere at top level a needed instance. Seems ok then 👍

Helio

01/20/2021, 8:11 PM

Awesome! Thanks for confirming. :)

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