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Merged
merged 1 commit into from
May 14, 2020
Merged

update(vm): use Flow instead of LiveData #2

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5 changes: 5 additions & 0 deletions .idea/codeStyles/Project.xml
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1 change: 0 additions & 1 deletion .idea/codeStyles/codeStyleConfig.xml
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7 changes: 2 additions & 5 deletions app/build.gradle
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Expand Up @@ -53,9 +53,6 @@ dependencies {
// lifecycleScope
implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.0-alpha02'

// Extensions for LiveData
implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.3.0-alpha02'

// retrofit2
implementation 'com.squareup.retrofit2:retrofit:2.8.1'
implementation 'com.squareup.retrofit2:converter-moshi:2.8.1'
Expand All @@ -65,8 +62,8 @@ dependencies {
implementation 'com.squareup.moshi:moshi-kotlin:1.9.2'

// coroutines
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.5'
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.5'
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.6'
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.6'

// koin
implementation 'org.koin:koin-androidx-viewmodel:2.1.5'
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27 changes: 0 additions & 27 deletions app/src/main/java/com/hoc/flowmvi/Event.kt
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This file was deleted.

18 changes: 12 additions & 6 deletions app/src/main/java/com/hoc/flowmvi/ui/add/AddActivity.kt
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Expand Up @@ -5,7 +5,6 @@ import android.util.Log
import android.view.MenuItem
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.isInvisible
import androidx.lifecycle.Observer
import androidx.lifecycle.lifecycleScope
import com.hoc.flowmvi.clicks
import com.hoc.flowmvi.databinding.ActivityAddBinding
Expand Down Expand Up @@ -41,11 +40,18 @@ class AddActivity : AppCompatActivity(), View {

private fun bindVM() {
// observe view model
addVM.viewState.observe(this, Observer { render(it ?: return@Observer) })
addVM.singleEvent.observe(
this,
Observer { handleSingleEvent(it?.getContentIfNotHandled() ?: return@Observer) }
)
lifecycleScope.launchWhenStarted {
addVM.viewState
.onEach { render(it) }
.catch { }
.collect()
}
lifecycleScope.launchWhenStarted {
addVM.singleEvent
.onEach { handleSingleEvent(it) }
.catch { }
.collect()
}

// pass view intent to view model
intents()
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43 changes: 22 additions & 21 deletions app/src/main/java/com/hoc/flowmvi/ui/add/AddVM.kt
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@@ -1,8 +1,8 @@
package com.hoc.flowmvi.ui.add

import androidx.core.util.PatternsCompat
import androidx.lifecycle.*
import com.hoc.flowmvi.Event
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import com.hoc.flowmvi.domain.entity.User
import com.hoc.flowmvi.domain.usecase.AddUserUseCase
import com.hoc.flowmvi.flatMapFirst
Expand All @@ -17,42 +17,43 @@ import kotlinx.coroutines.flow.*
@FlowPreview
@ExperimentalCoroutinesApi
class AddVM(private val addUser: AddUserUseCase) : ViewModel() {
private val initialVS = ViewState.initial()
private val _eventChannel = BroadcastChannel<SingleEvent>(capacity = Channel.BUFFERED)
private val _intentChannel = BroadcastChannel<ViewIntent>(capacity = Channel.BUFFERED)

private val _viewStateD = MutableLiveData<ViewState>().apply { value = initialVS }
val viewState: LiveData<ViewState> = _viewStateD.distinctUntilChanged()
val viewState: StateFlow<ViewState>

private val _eventD = MutableLiveData<Event<SingleEvent>>()
val singleEvent: LiveData<Event<SingleEvent>> get() = _eventD
val singleEvent: Flow<SingleEvent>

private val _intentChannel = BroadcastChannel<ViewIntent>(capacity = Channel.BUFFERED)
suspend fun processIntent(intent: ViewIntent) = _intentChannel.send(intent)

init {
val initialVS = ViewState.initial()

viewState = MutableStateFlow(initialVS)
singleEvent = _eventChannel.asFlow()

_intentChannel
.asFlow()
.toPartialStateChangesFlow()
.sendSingleEvent()
.scan(initialVS) { state, change -> change.reduce(state) }
.onEach { _viewStateD.value = it }
.onEach { viewState.value = it }
.catch { }
.launchIn(viewModelScope)
}


private fun Flow<PartialStateChange>.sendSingleEvent(): Flow<PartialStateChange> {
return onEach { change ->
_eventD.value = Event(
when (change) {
is PartialStateChange.ErrorsChanged -> return@onEach
PartialStateChange.AddUser.Loading -> return@onEach
is PartialStateChange.AddUser.AddUserSuccess -> SingleEvent.AddUserSuccess(change.user)
is PartialStateChange.AddUser.AddUserFailure -> SingleEvent.AddUserFailure(
change.user,
change.throwable
)
}
)
val event = when (change) {
is PartialStateChange.ErrorsChanged -> return@onEach
PartialStateChange.AddUser.Loading -> return@onEach
is PartialStateChange.AddUser.AddUserSuccess -> SingleEvent.AddUserSuccess(change.user)
is PartialStateChange.AddUser.AddUserFailure -> SingleEvent.AddUserFailure(
change.user,
change.throwable
)
}
_eventChannel.send(event)
}
}

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20 changes: 13 additions & 7 deletions app/src/main/java/com/hoc/flowmvi/ui/main/MainActivity.kt
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Expand Up @@ -7,7 +7,6 @@ import android.view.Menu
import android.view.MenuItem
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.isVisible
import androidx.lifecycle.Observer
import androidx.lifecycle.lifecycleScope
import androidx.recyclerview.widget.DividerItemDecoration
import androidx.recyclerview.widget.ItemTouchHelper
Expand Down Expand Up @@ -66,7 +65,7 @@ class MainActivity : AppCompatActivity(), View {

ItemTouchHelper(
SwipeLeftToDeleteCallback(context) cb@{ position ->
val userItem = mainVM.viewState.value?.userItems?.get(position) ?: return@cb
val userItem = mainVM.viewState.value.userItems[position]
removeChannel.offer(userItem)
}
).attachToRecyclerView(this)
Expand All @@ -75,11 +74,18 @@ class MainActivity : AppCompatActivity(), View {

private fun bindVM() {
// observe view model
mainVM.viewState.observe(this, Observer { render(it ?: return@Observer) })
mainVM.singleEvent.observe(
this,
Observer { handleSingleEvent(it?.getContentIfNotHandled() ?: return@Observer) }
)
lifecycleScope.launchWhenStarted {
mainVM.viewState
.onEach { render(it) }
.catch { }
.collect()
}
lifecycleScope.launchWhenStarted {
mainVM.singleEvent
.onEach { handleSingleEvent(it) }
.catch { }
.collect()
}

// pass view intent to view model
intents()
Expand Down
64 changes: 31 additions & 33 deletions app/src/main/java/com/hoc/flowmvi/ui/main/MainVM.kt
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@@ -1,8 +1,8 @@
package com.hoc.flowmvi.ui.main

import android.util.Log
import androidx.lifecycle.*
import com.hoc.flowmvi.Event
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import com.hoc.flowmvi.domain.usecase.GetUsersUseCase
import com.hoc.flowmvi.domain.usecase.RefreshGetUsersUseCase
import com.hoc.flowmvi.domain.usecase.RemoveUserUseCase
Expand All @@ -14,75 +14,73 @@ import kotlinx.coroutines.channels.BroadcastChannel
import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.flow.*

@Suppress("USELESS_CAST")
@FlowPreview
@ExperimentalCoroutinesApi
class MainVM(
private val getUsersUseCase: GetUsersUseCase,
private val refreshGetUsersUseCase: RefreshGetUsersUseCase,
private val removeUserUseCase: RemoveUserUseCase
private val refreshGetUsers: RefreshGetUsersUseCase,
private val removeUser: RemoveUserUseCase,
) : ViewModel() {
private val initialVS = ViewState.initial()
private val _eventChannel = BroadcastChannel<SingleEvent>(capacity = Channel.BUFFERED)
private val _intentChannel = BroadcastChannel<ViewIntent>(capacity = Channel.CONFLATED)

private val _viewStateD = MutableLiveData<ViewState>()
.apply { value = initialVS }
val viewState: LiveData<ViewState> = _viewStateD.distinctUntilChanged()
val viewState: StateFlow<ViewState>

private val _eventD = MutableLiveData<Event<SingleEvent>>()
val singleEvent: LiveData<Event<SingleEvent>> get() = _eventD
val singleEvent: Flow<SingleEvent>

private val _intentChannel = BroadcastChannel<ViewIntent>(capacity = Channel.CONFLATED)
suspend fun processIntent(intent: ViewIntent) = _intentChannel.send(intent)

init {
val intentFlow = _intentChannel.asFlow()
val initialVS = ViewState.initial()

viewState = MutableStateFlow(initialVS)
singleEvent = _eventChannel.asFlow()

val intentFlow = _intentChannel.asFlow()
merge(
intentFlow.filterIsInstance<ViewIntent.Initial>().take(1),
intentFlow.filterNot { it is ViewIntent.Initial }
)
.toPartialChangeFlow()
.sendSingleEvent()
.scan(initialVS) { vs, change -> change.reduce(vs) }
.onEach { _viewStateD.value = it }
.onEach { viewState.value = it }
.catch { }
.launchIn(viewModelScope)
}

private fun Flow<PartialChange>.sendSingleEvent(): Flow<PartialChange> {
return onEach {
_eventD.value = when (it) {
is PartialChange.GetUser.Error -> Event(SingleEvent.GetUsersError(it.error))
is PartialChange.Refresh.Success -> Event(SingleEvent.Refresh.Success)
is PartialChange.Refresh.Failure -> Event(SingleEvent.Refresh.Failure(it.error))
is PartialChange.RemoveUser.Success -> Event(SingleEvent.RemoveUser.Success(it.user))
is PartialChange.RemoveUser.Failure -> Event(
SingleEvent.RemoveUser.Failure(
user = it.user,
error = it.error
)
val event = when (it) {
is PartialChange.GetUser.Error -> SingleEvent.GetUsersError(it.error)
is PartialChange.Refresh.Success -> SingleEvent.Refresh.Success
is PartialChange.Refresh.Failure -> SingleEvent.Refresh.Failure(it.error)
is PartialChange.RemoveUser.Success -> SingleEvent.RemoveUser.Success(it.user)
is PartialChange.RemoveUser.Failure -> SingleEvent.RemoveUser.Failure(
user = it.user,
error = it.error,
)
PartialChange.GetUser.Loading -> return@onEach
is PartialChange.GetUser.Data -> return@onEach
PartialChange.Refresh.Loading -> return@onEach
}
_eventChannel.send(event)
}
}

private fun <T> Flow<T>.toPartialChangeFlow(): Flow<PartialChange> {
private fun Flow<ViewIntent>.toPartialChangeFlow(): Flow<PartialChange> {
val getUserChanges = getUsersUseCase()
.onEach { Log.d("###", "[MAIN_VM] Emit users.size=${it.size}") }
.map {
val items = it.map(::UserItem)
@Suppress("USELESS_CAST")
PartialChange.GetUser.Data(items) as PartialChange.GetUser
}
.onStart { emit(PartialChange.GetUser.Loading) }
.catch { emit(PartialChange.GetUser.Error(it)) }

val refreshChanges = flow { emit(refreshGetUsersUseCase()) }
.map {
@Suppress("USELESS_CAST")
PartialChange.Refresh.Success as PartialChange.Refresh
}
val refreshChanges = flow { emit(refreshGetUsers()) }
.map { PartialChange.Refresh.Success as PartialChange.Refresh }
.onStart { emit(PartialChange.Refresh.Loading) }
.catch { emit(PartialChange.Refresh.Failure(it)) }

Expand All @@ -91,11 +89,11 @@ class MainVM(
.logIntent()
.flatMapConcat { getUserChanges },
filterIsInstance<ViewIntent.Refresh>()
.filter { _viewStateD.value?.let { !it.isLoading && it.error === null } ?: false }
.filter { viewState.value.let { !it.isLoading && it.error === null } }
.logIntent()
.flatMapFirst { refreshChanges },
filterIsInstance<ViewIntent.Retry>()
.filter { _viewStateD.value?.error != null }
.filter { viewState.value.error != null }
.logIntent()
.flatMapFirst { getUserChanges },
filterIsInstance<ViewIntent.RemoveUser>()
Expand All @@ -104,7 +102,7 @@ class MainVM(
.flatMapMerge { userItem ->
flow {
try {
removeUserUseCase(userItem.toDomain())
removeUser(userItem.toDomain())
emit(PartialChange.RemoveUser.Success(userItem))
} catch (e: Exception) {
emit(PartialChange.RemoveUser.Failure(userItem, e))
Expand Down