The concept of MVI (and especially the TODO example App) seems to be a bit complicated and the difference to decompose is also not clear to me, so I am not sure if it fits to my needs: I have a key value database, which could be very large and not all data in it is needed all the time, so mirroring the database to Stores is not an option. I would need something like functions in a store to receive only specific data, which are loaded from database, but are also observable, when something changes (e. g. due to a server response). Is this doable with MVI or is it the wrong framework for something like that? Thanks 🙂

Hi, I'm trying to see how Labels are used in this example: https://github.com/JetBrains/compose-jb/blob/master/examples/todoapp/common/edit/s[…]/kotlin/example/todo/common/edit/store/TodoEditStoreProvider.kt from what I see, both setText and setDone methods are doing a dispatch to send out the result but they are also publishing labels which don't seem to be consumed by anything in the app? What would be their purpose in the code?

Lol, how did we end up posting a similar question at the same time

Hello again. I need to create a repository for a bluetooth connection. The bluetooth connection depends on a scope, that is, as long as the scope is valid, the connection remains active. I need this connection to be active for multiple screens. I thought about creating a store/component with application scope and sharing it with each screen. It's possible? Do you see another way to do this?

Hey, I was wondering how

subscribeScoped

works (I am used to the Singles having onError/Success) and how to handle errors in my usecase? I am currently making a request to the backend and it returns the status and data, ktor suspend request so I wrap it in

singleFromCoroutine

. Am I supposed to wrap the call in try catch? Eg

return singleFromCoroutine {
            try {     
 val response: HttpResponse =
               <http://client.post|client.post>("${serverUrl}${apiEndpoint}/account")
 
                return@singleFromCoroutine CreateAccountResponse(response.status.value)
            } catch (e: Exception) {
                return@singleFromCoroutine CreateAccountResponse(500, e.message ?: "")
            }

I feel like I am seriously missing something here, I can't properly handle errors as I have to have a half-assed response network model that has to hold both the data and the potential error. Or is this the way to go?

Just stumbled unto this, but after publishing a label in ReaktiveExecutor execute action (checking if user session is still valid) it doesn't get propagated to the store. Is this intended behavior? My code

private inner class ExecutorImpl : ReaktiveExecutor<Intent, Unit, State, Result, Label>() {
        override fun executeAction(action: Unit, getState: () -> State) {
            dispatch(Result.Loading())
            val user = firebaseAuth.currentUser
            if (user != null) {
                publish(Label.LoggedIn)
            }
        }

I am binding to the store.label output in the init block of the component

Hello everyone) First of all, thanks a lot for the greatest MVI library) Could someone recommend a way how to test Bootstrapper or Executor in isolation? I have complex logic there and want to verify that I am dispatching/publishing right events. The dispatch and publish methods are protected so I couldn’t get access to it to verify right argument.

Hi, I'm trying to use the bootstrapper based on the documentation but I'm not really understanding what I'm doing wrong here (using 3.0.0-alpha01 but it also happens on 2.0.4)

Hello everyone, how are you? can anyone help me with a question? In readme of Essenty library we have the following description about StateKeeper

When writing common code targetting Android, it might be required to preserve some data over Android configuration changes or process death.

what kind of process death that we must preserve some data??

Hey guys, using MVIKotlin with KotlinJS and React for web, anyone got a good setup for functional components and handling state/ passing props? I am trying to do something like this

external interface RootProps : PropsWithChildren {
    var component: Root
}

val RootC = fc<RootProps> { props ->
    val (routerState, _) = useState(props.component.routerState.value)

    val child: Root.Child = routerState.activeChild.instance

And I'd call this way in my toplevel app component

override fun RBuilder.render() {
        RootC {
            attrs {
                this.component = root
            }
        }
    }

But this doesn't seem to pickup on the state

val (routerState, _) = useState(props.component.routerState.value)

and doesn't update the component. No composables, so cannot use the ValueExt from the samples

Hello! I hope you can help me with understanding MVI architecture. I'm experimenting with MVIKotlin and I'm trying to create chat application. Lets assume that it will look like Slack client, then we all know what I'm talking about. My problem is what exactly "Component" is. Currently my app should have two screens: ConfigurationScreen and ConversationsScreen. ConversationsScreen contains list of channels on the left and messages history with input panel on the right. I assume that

ConfigurationScreen

and

ConversationsScreen

should be Component with their own stores, intents and results. For example

ConversationsScreen

state will have state containing

selectedChannel

. The question is: does

MessageHistoryWithInput

should be Component with their own store (containing: loaded message list), own intents (

SendMessage

,

LoadedMessageList

) etc? How to embed this component inside

ConversationsScreen

component? Does anyone has any example?

Is there a recommended way, how to use suspending code in Decompose

componentContext

? Should it contain a new CoroutineScope or should it expose suspending functions and the component should handle it (e. g. with

rememberCoroutineScope

)?

hi all, i use Decompose and my app currently has 2 screens. i would like to use a

Scaffold

and navigate with the

Drawer

(1 item for each screen in the drawer which will then change router state on click). Since the

Scaffold

has multiple parameters related to each screen (title, actions, content), i dont know if it should be part of the root content or part of each screen's content..? Let's say, i would use it as root content. Is it ok to check routerState/children for each

Scaffold

section and then call composable functions depending on the child for each section: Child1Title(), Child1Actions(), Child1Content()? (Are there any examples for

Drawer

navigation with Decompose?)

Hey everyone, I was trying to learn how to unit test a store in MVI using the

SuspendExecutor

and was wondering if anybody had a sample project where they could get a

runBlockingTest

to work? After some research it seems like the

runBlockingTest

in the coroutines test library is just supported on the JVM, but there is a workaround to get it to work per this comment. After adding that to my project, I still seem to run into a few issues when trying to run the test.

import com.arkivanov.mvikotlin.core.store.StoreFactory
import com.arkivanov.mvikotlin.main.store.DefaultStoreFactory
import com.plusmobileapps.shared.db.Activity
import com.plusmobileapps.wolfpack.activity.list.ActivityListStoreProvider
import com.plusmobileapps.wolfpack.di.DEFAULT_DISPATCHER_TAG
import com.plusmobileapps.wolfpack.di.MAIN_DISPATCHER_TAG
import com.plusmobileapps.wolfpack.mocks.ActivityRepositoryMock
import com.plusmobileapps.wolfpack.runBlockingTest
import kotlinx.coroutines.Dispatchers
import org.kodein.di.DI
import org.kodein.di.bind
import org.kodein.di.singleton
import kotlin.coroutines.CoroutineContext
import kotlin.test.Test
import kotlin.test.assertEquals

class ActivityListStoreTest {
    private val storeFactory = DefaultStoreFactory
    private val repository = ActivityRepositoryMock()

    private val di = DI {
        bind<CoroutineContext>(MAIN_DISPATCHER_TAG) { singleton { testCoroutineContext } }
        bind<CoroutineContext>(DEFAULT_DISPATCHER_TAG) { singleton { testCoroutineContext } }
        bind<ActivityRepository> { singleton { repository } }
        bind<StoreFactory> { singleton { storeFactory } }
    }

    @Test
    fun foo() = runBlockingTest {
        val activity = Activity(1L, "", true)
        repository.addActivity(activity)
        val store = ActivityListStoreProvider(di).provide()

        assertEquals(listOf(activity), store.state.activities)
    }
}

• For ios, keep getting an

InvalidMutabilityException

which I think is because the DI gets frozen inside the test because once something is retrieved from DI it throws the exception? • Then for android, keep getting

java.lang.RuntimeException: Method getMainLooper in android.os.Looper not mocked.

which am I supposed to import the coroutine test library on jvm tests to get them to work? I'm a little lost in the weeds trying to figure this out and might even consider switching to Reaktive as it seems to have a pretty good testing support from looking at the todo sample tests. Any help is greatly appreciated!

Related to the question from Reaktive channel, I was wondering how websockets work with stores/ what's the recommended way of working with them? Should I just subscribe to everything inside my Executors executeAction? As that's the only place you'll have access to state and dispatch/ publish

Hello! Mutable state is common source of bugs, specially with declarative UI frameworks. I suggest to always use immutable structures, unless you are really optimizing the performance with a profiler. So yes, copy data classes and it's lists and maps. You can add an entry to an immutable map as follows:

map = map + (key to value)

Hi. I have a component with few TextFields. I have Store and I have Intents like

SetPassword

SetUsername

SetDomain

etc. Should I for each Intent create corresponding Result (

SetPassword

-

PasswordChanged

,

SetUsername

-

UsernameChanged

), or there is simplest solution (but compliant with the best practices)?

quick suggestion for the mvikotlin docs...add a link to the jb compose sample: https://github.com/JetBrains/compose-jb/tree/master/examples/todoapp Also would help a bit to add a "where stuff is defined markdown page w/ links and how it works"...takes a while to figure out where stuff is in common etc.

Also, is there a simpler example that just uses it for Jetpack Compose on Android?

Both executeAction and executeIntent were suspending functions a while ago, but it was an explicit decision to make them normal. Looks like I forgot to update KDocs as well, thanks for pointing that. There is

scope

properly available which you can use to launch coroutines when needed. You can check samples: https://github.com/arkivanov/MVIKotlin/blob/master/sample/todo-coroutines/src/commonMain/kotlin/com/arkivanov/mvikotlin/sample/todo/coroutines/store/TodoListStoreFactory.kt The reason for this change is because now you are able to process intents and actions synchronously in the same call stack as they were dispatched.

Has anyone ever mentioned that it'd be less confusing if you Swap the naming of Result and Action? 🙂 Having executors send a result to a reducer is confusing because reducers usually take an intent and state to create a new state.

Hi! I stuck with one problem. I'm not sure if it is caused by Decompose or Compose Desktop, but I'm not able to reproduce it without router. I have master-detail application. When I click on master menu item, then I replace ruter configuration:

when (menuItem) {
	is SideMenu.MenuItem.DirectChatMenuItem -> router.replaceCurrent(Configuration.Conversation(menuItem.chat.openChatId))
	else -> router.replaceCurrent(Configuration.Nothing)
}

Here is child factory:

private fun createChild(
	configuration: Configuration, componentContext: ComponentContext,
): Child = when (configuration) {
	is Configuration.Conversation -> Child.Chat(
		ConversationMainComponent(componentContext, configuration.chatId, storeFactory)
	)
	is Configuration.Nothing -> Child.WelcomeScreen
}

ConversationMainComponent

contains

TextField

. When I show

ConversationMainComponent

first time and I make text field focused, then everything works fine. When I switch to different

DirectChatMenuItem

what creates different

ConversationMainComponent

and then I try to focus text field, I see exception:

Exception in thread "AWT-EventQueue-0" kotlin.UninitializedPropertyAccessException: lateinit property relocationRequesterNode has not been initialized
	at androidx.compose.ui.layout.RelocationRequesterModifier.getRelocationRequesterNode(RelocationRequesterModifier.kt:32)
	at androidx.compose.ui.layout.RelocationRequester.bringIntoView(RelocationRequester.kt:61)
	at androidx.compose.ui.layout.RelocationRequester.bringIntoView$default(RelocationRequester.kt:59)
	at androidx.compose.foundation.FocusableKt$focusable$2$4$1.invokeSuspend(Focusable.kt:108)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
	at androidx.compose.ui.platform.FlushCoroutineDispatcher$dispatch$2.invokeSuspend(CoroutineDispatchers.desktop.kt:55)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
	at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:313)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:770)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
	at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
	at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:740)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

Funny is, that when I select one direct chat, make field focused, then I select something else (

Child.WelcomeScreen

) and I select direct chat again, then everything works fine. Any advice? :-)

Hi - on iOS I’m seeing lots of MVIKotlin logging in console. Is there a way to disable the default logging? I’m worried about it causing perf issues in production. I’ve tried to comment out mvikotlin-logging from gradle but there’s still lots of logging. Do I need to implement a custom logger that doesn’t log anything? Thanks Example:

[MVIKotlin]: ListStore (STATE, State):

Hi, I have updated to the 0.4.0 release of Decompose. The

ComponentContext

now only exposes a

BackPressedHandler

which can be used to register handlers for the back-button. I have several unit tests that verify the correct behaviour of the back button action which I have initiated with

onBackPressed()

which is now missing. How can I simulate a back-button pressed in a unit test? Thanks.

Hello everyone! A few times I received feedback that there is some boilerplate when implementing a Store. I have some ideas of how to improve things, but I would like to run a poll first. Could you please vote how do you like the current experience? Thanks! 🙂 - I like the current experience, don't touch! 😐 - Would be good to improve 🙁 - Definitely needs improvement! 🙃 - I don't care

Is it a good idea to have a component of dynamic on demand feature as nullable child component? https://gist.github.com/rustamsmax/b8768f4546d8a4b1eb256402527f6f8c

Hi, I don’t know if it is the right channel for this: I am exploring MVIKotlin et Decompose to potentially integrate them in my project I am testing the basic Counter with Decompose on iOS and there is a

Value

class in

ObservableValue

that is not found by XCode (I cloned the sample and I am not able to find with the sample either) Would you guys be able to tell me what I am missing here ? Thanks !

Hello, a decompose question. I have the following config, (screens are components + stores practically) Screen A has two children, Nothing and Child B (screen B). When Nothing is the child, screen A displays its content, when the child is B then it shows screen B. Practically corresponding (since it's a web app) to

url/user/

and

url/user/profile/

I am having issues with going back and navigating to screen A again. If I am on screen B, I cannot press back on my mouse and the browser doesn't give me the back option. Also when navigating from some other screen back to screen A, it still contains Configuration B, because I cannot push a new configuration (getting the unique Config error), so I am using the

pushToFront

. What would be the approach, besides adding a back button on desktop to go about this? (I think that mobile handles the back button normally, would have to test it). Also, I am not really proficient in web dev, would it be possible to have URLs and have them go back option with Decompose and Web?

What is the prefered way of sending one time events to the UI from the stores? Example, we have a success and want to notify the user, I'd emit a Label and I'd be able to catch it in the Component, but how can I send it from Component -> UI?