An Android Dev start to Kotlin MPP

Transcript

1. An Android Dev start to Kotlin MPP
2. Premises I want to reuse my knowledge I am an Android Dev I don’t want to be x-plat
3. What about languages?
4. Or actually any other example Empire State Building Lights Calendar App
5. Architecture Activity ViewModel Repository
6. Libraries Repository Retrofit Gson / Moshi
7. Libraries Repository Retrofit Gson / Moshi Ktor kotlinx.serializer
8. Modularization Activity ViewModel Repository Native module Shared module
9. Modularization Repository Shared module
11. There is an app a plugin for that. PROJECT SETUP 1
12. Install & Profit
13. Create the project
14. Create the project
15. WRITE SOME CODE 2
16. expect actual IDE only helps after the directories have been created.
17. @Serializable data class DayLight( val image: String, val color: String, val reason: String, val date: String ) @Serializable data class Lights( val todayColor: String, val picture: String, val calendar: List<DayLight> ) :shared
18. class LightRepository { private val httpClient = HttpClient { install(JsonFeature) { val json = Json { ignoreUnknownKeys = true } serializer = KotlinxSerializer(json) } } suspend fun getLights() : Lights = httpClient.get(LIGHTS_ENDPOINT) } :shared
19. :android class LightsViewModel : ViewModel() { private val repository by lazy { LightRepository() } private val _state : MutableLiveData<Lce<Lights>> = MutableLiveData() val state : LiveData<Lce<Lights>> get() = _state fun loadLights() { _state.postValue(Lce.Loading) viewModelScope.launch { try { val lights = repository.getLights() _state.postValue(Lce.Success(lights)) } catch(e: Exception) { _state.postValue(Lce.Error(e)) } } } }
20. val state : LiveData<Lce<Lights>> get() = _state fun loadLights() { _state.postValue(Lce.Loading) viewModelScope.launch { try { val lights = repository.getLights() _state.postValue(Lce.Success(lights)) } catch(e: Exception) { _state.postValue(Lce.Error(e)) } }
21. They will happen WEIRD ERRORS 3
23. Delete all .iml files in the project Close project and IDE Delete .idea directory Re-import the project
25. upgrade Gradle to 6.7 (KT-43039)
27. bit.ly/KMM-Codelab
28. USE COROUTINES 4
30. REMEMBER You cannot use extension functions
31. extension ContentView { enum LoadableLights { case loading case result(Lights) case error(String) } class ViewModel: ObservableObject { let repo : LightRepository @Published var lights = LoadableLights.loading init(repo: LightRepository){ self.repo = repo self.loadLights() } func loadLights() { self.lights = .loading repo.getLights(completionHandler: { lights, error in if let lights = lights { self.lights = .result(lights) } else { self.lights = .error(error?.localizedDescription ?? "error") } }) } } }
32. self.repo = repo self.loadLights() } func loadLights() { self.lights = .loading repo.getLights(completionHandler: { lights, error in if let lights = lights { self.lights = .result(lights) } else { self.lights = .error(error?.localizedDescription ?? "e } }) }
33. private func listView() -> AnyView { switch viewModel.lights { case .loading: return AnyView(Text("Loading...").multilineTextAlignment(.center)) case .result(let lodableLights): return AnyView(LightsView(lights: lodableLights)) case .error(let description): return AnyView(Text(description).multilineTextAlignment(.center)) } }
36. Hello! I Am Rob Follow me at @_tiwiz
37. Q&A