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DroidKaigi LogoDroidKaigi 2020 official Android app

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The DroidKaigi 2020 event has been canceled and development is inactive, but we'd love to hear from you if you have any improvements.

You can install the production app via Get it on Google Play.

<img src="https://play.google.com/intl/ja/badges/static/images/badges/en_badge_web_generic.png" alt="You can install the production app via Get it on Google Play" width="155px">

And also, you can try the binary under development built on master branch through Try it on your device via DeployGate

   <img src="https://dply.me/qo28h3/button/large" alt="Try it on your device via DeployGate">

Features

topdrawer
<img src="arts/top.png" width="250px" /><img src="arts/drawer.png" width="250px" />

Contributing

We always welcome any and all contributions! See CONTRIBUTING.md for more information

For Japanese speakers, please see CONTRIBUTING.ja.md

Requirements

Android Studio 3.6 and higher. You can download it from this page.

Development Environment

Multi module project

We separate the modules for each feature. We use the Dynamic feature modules for additional features.

<img src="arts/multimodule.png" width="400px" />

Kotlin Multiplatform Project

This app uses Kotlin Multiplatoform to share API and model classes (such as Session and Room classes) between Android and iOS.

Architecture

This app uses an AndroidJetpack(AAC) based architecture using AAC(LiveData, ViewModel, Room), Kotlin, Kotlin Coroutines Flow, DataBinding, Dagger, Firebase.

<img src="arts/arch1.png" width="400px" />

It is designed to be a unidirectional data flow within the ViewModel.

<img src="arts/arch2.png" width="400px" />

Fragment

<img src="arts/fragment.png" width="400px" />

Just observe() the LiveData<UiModel> of the ViewModel.

@Inject lateinit var sessionDetailViewModelFactory: SessionDetailViewModel.Factory
private val sessionDetailViewModel by assistedViewModels {
    sessionDetailViewModelFactory.create(navArgs.sessionId)
}

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)
    ...
    sessionDetailViewModel.uiModel
        .observe(viewLifecycleOwner) { uiModel: SessionDetailViewModel.UiModel ->
            ...
            progressTimeLatch.loading = uiModel.isLoading
            uiModel.session
                ?.let { session -> setupSessionViews(session) }
        }
    }

ViewModel

<img src="arts/viewmodel1.png" width="400px" />

The LiveData Kotlin Coroutines builder runs when LiveData becomes active.
And observe the data of the Coroutiens Flow of the repository.

The LiveData becomes LoadState.Loading before the Coroutiens Flow is executed by Flow.toLoadingState(), and becomes LoadState.Loaded when finished.

class SessionsViewModel @Inject constructor(
    val sessionRepository: SessionRepository
) : ViewModel() {

...
    private val sessionLoadState: LiveData<LoadState<SessionContents>> = liveData {
        emitSource(
            sessionRepository.sessionContents()
                .toLoadingState()
                .asLiveData()
        )
        sessionRepository.refresh()
    }
<img src="arts/viewmodel2.png" width="400px" />

Construct UiModel LiveData from some such LiveData.
The combine method works like RxJava's combineLatest.
You can make the loading state of the screen from multiple LiveData states like sessionLoadState.isLoading || favoriteState.isLoading.

class SessionDetailViewModel @AssistedInject constructor(
    @Assisted private val sessionId: SessionId,
    private val sessionRepository: SessionRepository
) : ViewModel() {
...
    val uiModel: LiveData<UiModel> = combine(
        initialValue = UiModel.EMPTY,
        liveData1 = sessionLoadStateLiveData,
        liveData2 = favoriteLoadingStateLiveData
    ) { current: UiModel,
        sessionLoadState: LoadState<Session>,
        favoriteState: LoadingState ->
        // You can create loading state by multiple LiveData
        val isLoading = sessionLoadState.isLoading || favoriteState.isLoading
        UiModel(
            isLoading = isLoading,
            error = sessionLoadState
                .getErrorIfExists()
                .toAppError()
                ?: favoriteState
                    .getErrorIfExists()
                    .toAppError()
            ,
            session = sessionLoadState.value
        )
    }

Run Coroutines with viewModelScope when data changes, such as adding a session to Favorites.
Because we do not want to end the process of adding a session to favorites with the back button, we use WorkManager to do the processing.

<img src="arts/viewmodel3.png" width="400px" /> 
class SessionDetailViewModel @AssistedInject constructor(
    @Assisted private val sessionId: SessionId,
    private val sessionRepository: SessionRepository
) : ViewModel() {
..
    private var favoriteLoadingStateLiveData: MutableLiveData<LoadingState> = MutableLiveData(LoadingState.Loaded)
...
    fun favorite(session: Session) {
        viewModelScope.launch {
            favoriteLoadingStateLiveData.value = LoadingState.Loading
            try {
                sessionRepository.toggleFavoriteWithWorker(session.id)
                favoriteLoadingStateLiveData.value = LoadingState.Loaded
            } catch (e: Exception) {
                favoriteLoadingStateLiveData.value = LoadingState.Error(e)
            }
        }
    }

Design

<img src="arts/design.png" width="400px" />

Thanks

Thank you for contributing!

Credit

This project uses some modern Android libraries and source codes.

Android

iOS