[22]Efficient and Testable MVVM pattern

Efficient and Testable MVVM pattern
Session 2. Android archietecture
@omjoonkim
with using AAC, Rx, Koin

MVC
MVP
MVVM
MVI
VIPER
etc…
with CleanArchitecture
with RFP(rxJava2)
with AAC, Koin
with Spek

Presenter code 1000Line 😨
😓
( ) 🤕
View Presenter 🤒
☝
Business Logic ☝
☝
☝
👇
👇

MVVM….
- Model View ViewModel
- ViewModel View .
- View ViewModel n:m .
- View ViewModel bindable .

Model View ViewModel
VIEW
VIEW
MODEL
MODEL
DataBinding
Notification
Update
Notification

ViewModel View .
- ViewModel View .
- ViewModel View input output .
- input output .
- (input) (output) .
- .
- output View Route .

View ViewModel n:m .
- View ViewModel .
- ViewModel View .
- .

VIEW
VIEW
MODEL
MODEL
DataBinding
View ViewModel bindable .
Notification Notification
Update

View ViewModel bindable .
- View ViewModel .
- (View -> ViewModel)
- View (ViewModel -> View)
- PS. binding .

…
VIEW
VIEW
MODEL
MODEL
DataBinding
Databinding,
LiveData
RxJava
View  
ViewModel
.
binding input output
.
Databinding
.

How MVVM?
Efficiently
Testable

on Android? 🤔
VIEW
VIEW
MODEL
MODEL
DataBinding
Notification
Update
Notification

on Android! 🙌
VIEW
VIEW
MODEL
MODEL
DataBinding
LiveData
UseCase
Rx

VIEW
VIEW
MODEL
MODEL
DataBinding
LiveData
UseCase
Rx
XML
(databindingUtil)
Activity
or Fragment
or something
on Android! 🙌

VIEW
VIEW
MODEL
MODEL
DataBinding
LiveData
UseCase
Rx
XML
(databindingUtil)
Activity
or Fragment
or something
View
Router + ViewModel View binding
.
on Android! 🙌

✨
- CleanArchitecture
- Koin IOC(Inversion Of Control)
- Spek .

https://github.com/omjoonkim/GitHubBrowserApp
✨

package
App
Data
Domain
Remote

CleanArchitecture
UI
Data
Domain
Remote
Presentation
Koin!

Koin?
- Library.(DI x)
- Kotlin .
- !
- AAC ✨
- Service Locator .
- Runtime .

Koin!
val myModule: Module = module {
viewModel { (id: String) -> MainViewModel(id, get(), get()) }
viewModel { SearchViewModel(get()) }
//app
single { Logger() }
single { AppSchedulerProvider() as SchedulersProvider }
//domain
single { GetUserData(get(), get()) }
//data
single { GithubBrowserDataSource(get()) as GitHubBrowserRepository }
//remote
single { GithubBrowserRemoteImpl(get(), get(), get()) as GithubBrowserRemote }
single { RepoEntityMapper() }
single { UserEntityMapper() }
single {
GithubBrowserServiceFactory.makeGithubBrowserService(
BuildConfig.DEBUG,
"https://api.github.com"
)
}
}

Koin!
class App : Application() {
override fun onCreate() {
super.onCreate()
startKoin(
this,
listOf(myModule)
)
}
}

SearchView - Input?
name
clickSearchButton

SearchView - Output?
STATE
enableSearchButton
Route
goResultActivity

SearchViewModel - constructor
class SearchViewModel(
logger: Logger
) : BaseViewModel()

BaseViewModel
abstract class BaseViewModel : ViewModel(){
protected val compositeDisposable : CompositeDisposable = CompositeDisposable()
override fun onCleared() {
super.onCleared()
compositeDisposable.clear()
}
}

SearchViewModel - input, output, state
interface SearchViewModelInPuts : Input {
fun name(name: String)
fun clickSearchButton()
}
interface SearchViewModelOutPuts : Output {
fun state(): LiveData<SearchViewState>
fun goResultActivity(): LiveData<String>
}
data class SearchViewState(
val enableSearchButton: Boolean
)

SearchViewModel - properties
private val name = PublishSubject.create<String>()
private val clickSearchButton = PublishSubject.create<Parameter>()
val input = object : SearchViewModelInPuts {
override fun name(name: String) =
this@SearchViewModel.name.onNext(name)
override fun clickSearchButton() =
this@SearchViewModel.clickSearchButton.onNext(Parameter.CLICK)
}
private val state = MutableLiveData<SearchViewState>()
private val goResultActivity = MutableLiveData<String>()
val output = object : SearchViewModelOutPuts {
override fun state() = state
override fun goResultActivity() = goResultActivity
}

SearchViewModel - logic
init {
compositeDisposable.addAll(
name.map { SearchViewState(it.isNotEmpty()) }
.subscribe(state::setValue, logger::d),
name.takeWhen(clickSearchButton) { _, t2 -> t2 }
.subscribe(goResultActivity::setValue, logger::d)
)
}

SearchView
<data>
<import type="android.view.View"/>
<variable
name="viewModel"
type="com.omjoonkim.app.githubBrowserApp.viewmodel.SearchViewModel"
/>
</data>

SearchView - Databinding
<EditText
android:id="@+id/editText"
android:layout_width="match_parent"
android:layout_height="48dp"
android:onTextChanged='@{(s,start,end,before) -> viewModel.input.name(s.toString ?? "")}'
/>
<Button
android:id="@+id/button_search"
android:layout_height="wrap_content"
android:enabled="@{viewModel.output.state().enableSearchButton}"
android:onClick="@{(v) -> viewModel.input.clickSearchButton()}"
android:text="search"
/>

SearchActivity
class SearchActivity : BaseActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val binding = DataBindingUtil.setContentView<ActivitySearchBinding>(this,…)
binding.setLifecycleOwner(this)
val viewModel = getViewModel<SearchViewModel>()
binding.viewModel = viewModel
viewModel.output.goResultActivity()
.observe {
startActivity(
Intent(
Intent.ACTION_VIEW,
Uri.parse("githubbrowser://repos/$it")
)
)
}
}
}

SearchActivity - state binding
.observe {
startActivity(
Intent(
Intent.ACTION_VIEW,
)
)
}
}
}

SearchActivity - router binding
.observe {
startActivity(
Intent(
Intent.ACTION_VIEW,
)
)
}
}
}

ResultView - Input?
clickHomeButton
clickUser

ResultView - Output?
STATE
title
showLoading
ROUTER
refreshListData
finish
showErrorToast
goProfileActivity

MainViewModel - constructor
class MainViewModel(
searchedUserName: String,
private val getUserData: GetUserData,
logger: Logger
) : BaseViewModel()

MainViewModel - input, output, state
interface MainViewModelInputs : Input {
fun clickUser(user: User)
fun clickHomeButton()
}
interface MainViewModelOutPuts : Output {
fun state(): LiveData<MainViewState>
fun refreshListData(): LiveData<Pair<User, List<Repo>>>
fun showErrorToast(): LiveData<String>
fun goProfileActivity(): LiveData<String>
fun finish(): LiveData<Unit>
}
data class MainViewState(
val showLoading: Boolean,
val title: String
)

MainViewModel - properties
private val clickUser = PublishSubject.create<User>()
private val clickHomeButton = PublishSubject.create<Parameter>()
val input: MainViewModelInputs = object : MainViewModelInputs {
override fun clickUser(user: User) = clickUser.onNext(user)
override fun clickHomeButton() = clickHomeButton.onNext(Parameter.CLICK)
}
private val state = MutableLiveData<MainViewState>()
private val refreshListData = MutableLiveData<Pair<User, List<Repo>>>()
private val showErrorToast = MutableLiveData<String>()
private val goProfileActivity = MutableLiveData<String>()
private val finish = MutableLiveData<Unit>()
val output = object : MainViewModelOutPuts {
override fun state() = state
override fun refreshListData() = refreshListData
override fun showErrorToast() = showErrorToast
override fun goProfileActivity() = goProfileActivity
override fun finish() = finish
}

MainViewModel - logic
init {
val error = PublishSubject.create<Throwable>()
val userName = Observable.just(searchedUserName).share()
val requestListData = userName.flatMapMaybe {
getUserData.get(it).neverError(error)
}.share()
Observables
.combineLatest(
Observable.merge(
requestListData.map { false },
error.map { false }
).startWith(true),
userName,
::MainViewState
).subscribe(state::setValue, logger::d),
requestListData.subscribe(refreshListData::setValue, logger::d),
error.map {
if (it is Error)
it.errorText
else UnExpected.errorText
}.subscribe(showErrorToast::setValue, logger::d),
clickUser.map { it.name }.subscribe(goProfileActivity::setValue, logger::d),
clickHomeButton.subscribe(finish::call, logger::d)
)

val error = PublishSubject.create<Throwable>()
val userName = Observable.just(searchedUserName).share()
val requestListData = userName.flatMapMaybe {
getUserData.get(it).neverError(error)
}.share()

Observables
.combineLatest(
Observable.merge(
requestListData.map { false },
error.map { false }
).startWith(true),
userName,
::MainViewState
).subscribe(state::setValue, logger::d),
requestListData.subscribe(refreshListData::setValue, logger::d),
error.map {
if (it is Error)
it.errorText
else UnExpected.errorText
}.subscribe(showErrorToast::setValue, logger::d),
clickUser.map { it.name }.subscribe(goProfileActivity::setValue, logger::d),
clickHomeButton.subscribe(finish::call, logger::d)
)

MainView
<data>
<import type="android.view.View"/>
<variable
name="viewModel"
type="com.omjoonkim.app.githubBrowserApp.viewmodel.MainViewModel"
/>
</data>

MainView - Databinding
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:layout_height="?attr/actionBarSize"
app:title="@{viewModel.output.state().title}"
/>
<FrameLayout
android:layout_width="0dp"
android:layout_height="0dp"
android:visibility="@{viewModel.output.state().showLoading ? View.VISIBLE : View.GONE}"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@id/appBar"
>
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
/>
</FrameLayout>

MainActivity
val binding = DataBindingUtil.setConten…..
val viewModel = getViewModel<MainViewModel> {
parametersOf(intent.data.path.substring(1))
}
actionbarInit(binding.toolbar, onClickHomeButton = {
viewModel.input.clickHomeButton()
})

MainActivity
with(viewModel.output) {
refreshListData().observe { (user, repos) ->
binding.recyclerView.adapter = MainListAdapter(
user,
repos,
viewModel.input::clickUser
)
}
showErrorToast().observe { showToast(it) }
goProfileActivity().observe {
startActivity(
Intent(
Intent.ACTION_VIEW,
)
)
}
finish().observe {
onBackPressed()
}
}

HOW? 😎
-
- Test SchedulersProvider .
- Test DummyApiService .
- Spek + LiveData .
- Spek
- Feature
- Scenario
- Given
- When
- Then

TestSchedulerProvider
class TestSchedulerProvider : SchedulersProvider {
override fun io() = Schedulers.trampoline()
override fun ui() = Schedulers.trampoline()
}

TestDummyGithubBrowserService
class TestDummyGithubBrowserService : GithubBrowserService {
override fun getUserInfo(userName: String): Single<UserModel> =
Single.just(
UserModel("omjoonkim", "")
)
override fun getUserRepos(userName: String): Single<List<RepoModel>> =
Single.just(
listOf(
RepoModel("repo1", "repo1 description", "1"),
RepoModel("repo2", "repo2 description", "2"),
RepoModel("repo3", "repo3 description", "3")
)
)
}

DI for Test
val testModule = module {
single(override = true) {
TestSchedulerProvider() as SchedulersProvider
}
single(override = true) {
TestDummyGithubBrowserService() as GithubBrowserService
}
}
val test_module = listOf(myModule, testModule)

for Spek + LiveData
beforeEachTest {
ArchTaskExecutor.getInstance().setDelegate(object : TaskExecutor() {
override fun executeOnDiskIO(runnable: Runnable) {
runnable.run()
}
override fun isMainThread(): Boolean {
return true
}
override fun postToMainThread(runnable: Runnable) {
runnable.run()
}
})
}
afterEachTest {
ArchTaskExecutor.getInstance().setDelegate(null)
}

MainViewModelSpec
object MainViewModelSpec : KoinSpek({
beforeEachTest {…}
afterEachTest {…}
lateinit var userName: String
val viewModel: MainViewModel by inject { parametersOf(userName) }
val getUserData: GetUserData by inject()
Feature("MainViewModel spec") {…}
})

Scenario1
Scenario(" , ") {
Given(" omjoonkim "){
userName = "omjoonkim"
}
Then(" ") {
assertEquals(
getUserData.get(userName).blockingGet(),
viewModel.output.refreshListData().value
)
}
}

Scenario2
Scenario(" ") {
When(" ") {
viewModel.input.clickUser(
viewModel.output.refreshListData().value?.first
?: throw IllegalStateException()
)
}
Then(" ") {
assertEquals(
viewModel.output.refreshListData().value?.first?.name
?: throw IllegalStateException(),
viewModel.output.goProfileActivity().value
)
}
}

Scenario3
Scenario(" .") {
When(" ") {
viewModel.input.clickHomeButton()
}
Then(" .") {
assertEquals(
Unit,
viewModel.output.finish().value
)
}
}

Dagger2 vs Koin
- Heavy vs light
- Dependency Injection vs ServiceLocator
- CompileTime vs RunTime
https://twitter.com/jakewharton/status/908419644742098944

Spek Koin
- Spek + Koin .
- Spek Koin
https://github.com/InsertKoinIO/koin/pull/107

+
- Datbinding kotlin 100% .
- xml .
- Router
- Presentation module

[22]Efficient and Testable MVVM pattern

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