Android Architecture

Android Architecture presentation @dutchaug meetup at ING

Transcript

1. 09-06-17 1 Android Architecture
2. Jordy Langen @Jordy_Langen JordyLangen
3. Presenter Model View Intent Model View vs
4. Presenter Model View Intent Model View vs User
5. Architecture Goals • Highly testable • Highly maintainable and easy reviewing • Separations of concern • Avoid the God of all things (Activity) as much as possible • Activity != View • Minimal amount of boiler plate code • Keep it simple, stupid • Dependency injection friendly • Everything is a stream (Rx) • Reusable components • lol not fragments
6. Activity Component X Component Y
7. Activity Component X Component Y Presenter Model View
8. Presenter Model View
9. Presenter Model View Dashboard Presenter Dashboard Model Dashboard View
10. Dashboard Presenter Dashboard Model Dashboard View
11. Dashboard Presenter Dashboard Model Dashboard View data class Profile(val id: Int, var name: String = "", @Gender var gender: Int = FEMALE, var birthDate: Date = Date(), var height: Int = 0, var weightGoal: Int = 0, var goals: List<Int> = listOf(), val measurements: MutableList<Measurement> = mutableListOf() // other properties )
12. Dashboard Presenter Dashboard Model Dashboard View class DashboardView @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyle: Int = 0) : LinearLayout(context, attrs, defStyle) { fun showProfile(profile: Profile) { ... } fun showMeasurementsCallToAction() { ... } fun showLatestMeasurement() { ... } }
13. Dashboard Presenter Dashboard Model Dashboard View class DashboardViewCoordinator( private val profilesRepository: ProfilesRepository) : Coordinator() { private lateinit var dashboardView: DashboardView override fun attach(view: View) { dashboardView = view as DashboardView profilesRepository.getActiveProfile() .subscribe{ profile -> dashboardView.showProfile(profile) if (profile.measurements.isEmpty()) { dashboardView.showMeasurementsCallToAction() } else { dashboardView.showLatestMeasurement() } ... } } } Simple MVWhatever for Android: https://github.com/square/coordinators
14. tells it what to display Dashboard Presenter Dashboard Model Dashboard View model retrieval and updating
17. What about • Presenter state • Requesting permissions • startActivityForResult • Component to component communication • (presenter to presenter)
18. Presenter state
19. Presenter state Activity X Presenter View Repository load model
20. Presenter state Activity X Repository
21. Presenter state Activity X Presenter View new new Repository load model
22. Requesting permissions / startActivityForResult
23. Presenter View EventBus (Rx) Activity request permissions or results observes observes notifies Requesting permissions / startActivityForResult
24. Component to component communication
25. Dashboard Presenter Dashboard View EventBus (Rx) Weight Presenter Weight View sends event “update weight” observes Component to component communication
26. Dashboard Presenter Dashboard View EventBus (Rx) Weight Presenter Weight View sends event “update weight” observes X Presenter X View observes Component to component communication
28. Architecture Goals • Highly testable • Highly maintainable and easy reviewing • Separations of concern • Avoid the God of all things (Activity) as much as possible • Activity != View • Minimal amount of boiler plate code • Keep it simple, stupid • Dependency injection friendly • Everything is a stream (Rx) • Reusable components • lol not fragments
29. • Activity != View • Minimal amount of boiler plate code • Keep it simple, stupid • Dependency injection friendly • Everything is a stream (Rx) • Reusable components • lol not fragments • Minimal amount of logic in presenters • Separation of data storage and business logic • Proper models • Better way of handling user interaction
30. Intent Model View User https://github.com/JordyLangen/vaultbox
32. Intent Model View openVault Intent Vaults Model Vaults View
33. Intent Model View data class Vault( val name: String, val path: String)
34. data class VaultsViewState(val isLoading: Boolean, val vaults: List<Vault>) Intent Model View data class VaultsViewState( val isLoading: Boolean, val vaults: List<Vault>) Entity Model data class Vault( val name: String, val path: String)
35. data class VaultsViewState(val isLoading: Boolean, val vaults: List<Vault>) Intent Model View data class VaultsViewState( val isLoading: Boolean, val vaults: List<Vault>) Entity Model data class Vault( val name: String, val path: String) I realized we never really had a “model”
36. data class VaultsViewState(val isLoading: Boolean, val vaults: List<Vault>) Intent Model View class VaultsView @JvmOverloads constructor( context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0 ) : RelativeLayout(context, attrs, defStyleAttr), StateRenderer<VaultsViewState> override fun render(state: VaultsViewState) { if (state.isLoading) { vaults_view_progressbar.visibility = View.VISIBLE updateAdapter(emptyList()) } else { vaults_view_progressbar.visibility = View.GONE updateAdapter(state.vaults) } } }
37. data class VaultsViewState(val isLoading: Boolean, val vaults: List<Vault>) Intent Model View class VaultsView @JvmOverloads constructor( context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0 ) : RelativeLayout(context, attrs, defStyleAttr), StateRenderer<VaultsViewState> override fun render(state: VaultsViewState) { if (state.isLoading) { vaults_view_progressbar.visibility = View.VISIBLE updateAdapter(emptyList()) } else { vaults_view_progressbar.visibility = View.GONE updateAdapter(state.vaults) } } }
38. data class VaultsViewState(val isLoading: Boolean, val vaults: List<Vault>) Intent Model View class VaultsView @JvmOverloads constructor( context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0 ) : RelativeLayout(context, attrs, defStyleAttr), StateRenderer<VaultsViewState> val openVaultIntents: Observable<Vault> get() = onVaultClickRelay // a RxRelay PublishRelay override fun render(state: VaultsViewState) { // render logic } }
39. Intent Model View User
40. Intent Model View User Presenter notifies updates rendered by
41. Presenter class VaultsViewCoordinator(var vaultService: VaultService) : Coordinator<VaultsViewState, VaultsView>() { override var state: VaultsViewState = VaultsViewState(true, emptyList()) override fun attach(view: VaultsView) { view.render(state) // tying it all together here } // ... }
42. Presenter state
43. abstract class Coordinator<TState, in TStateRenderer : StateRenderer<TState>> { var isAttached: Boolean = false internal set abstract var state: TState open fun attach(view: TStateRenderer) { } open fun detach(view: TStateRenderer) { } } Presenter state
44. class StateStore { // works based on the assumption that view id + activity name is unique // if you use an id twice in the same view tree, well that's just on you companion object { private val states: MutableList<StateHolder<*>> = mutableListOf() fun <TState> update(id: Int, state: TState, context: Context) { ... } fun <TState> resolve(id: Int, context: Context): TState? { ... } fun markFinished(context: Context) { ... } } private data class StateHolder<out TState>( val viewId: Int, val state: TState, val contextName: String, var activityFinished: Boolean = false) } Presenter state
45. internal class Binding<in TState, TView : StateRenderer<TState>>( private val coordinator: Coordinator<TState, TView>, private val view: View) : View.OnAttachStateChangeListener { private var attached: View? = null override fun onViewAttachedToWindow(attachedView: View) { attached = attachedView coordinator.isAttached = true val state = StateStore.resolve<TState>(view.id, view.context) if (state != null) { coordinator.state = state } StateStore.update(view.id, coordinator.state, view.context) coordinator.attach(view as TView) } override fun onViewDetachedFromWindow(view: View) { StateStore.update(view.id, coordinator.state, view.context) attached = null coordinator.detach(this.view as TView) coordinator.isAttached = false this.view.setTag(R.id.coordinator, null) } } https://github.com/square/coordinators/…/Binding.java Presenter state
46. class VaultsViewCoordinator(var vaultService: VaultService) : Coordinator<VaultsViewState, VaultsView>() { override var state: VaultsViewState = VaultsViewState(true, emptyList()) override fun attach(view: VaultsView) { view.render(state) } // ... } Presenter state
47. class VaultsViewCoordinator(var vaultService: VaultService) : Coordinator<VaultsViewState, VaultsView>() { override var state: VaultsViewState = VaultsViewState(true, emptyList()) override fun attach(view: VaultsView) { view.render(state) } // ... } Presenter state
48. Minimal amount of logic in presenters
49. VaultsView Coordinator Vault Service Vault Repository Presentation logic Business logic Data access (also applies to MVP) Minimal amount of logic in presenters
50. Component to component communication
51. (also applies to MVP) VaultsView Coordinator Vault Service Vault Repository Presentation logic Business logic Data access VaultView Coordinator Component to component communication selectedVault: Observable<Vault>
52. Requesting permissions
53. VaultsView Coordinator Vault Service Vault Repository Presentation logic Business logic Data access (also applies to MVP) Permission Service Activity observe permission requests request(permission: String) : Observable<String> Requesting permissions
54. (also applies to MVP) fun findAll(): Observable<List<Vault>> { return permissionService.request(Manifest.permission.READ_EXTERNAL_STORAGE) .flatMap { grantedPermission -> Observable.just(grantedPermission == Manifest.permission.READ_EXTERNAL_STORAGE)) } .flatMap { isGranted -> if (isGranted) vaultRepository.findAll() else Observable.empty() } } Requesting permissions
55. Conclusion
56. Conclusion
57. Conclusion Highly testable code Reusable components Separation of data storage and business logic No crazy amount of magic needed to implement
59. Special thanks to Pieter Otten for reviewing
60. Special thanks to Pieter Otten for reviewing and saying “Is that really the style you are going for? This is not the final version is it?” “Really?!”
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62. Any questions?