Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Model View Intent - An Introduction
Search
Jossi Wolf
August 16, 2017
Programming
0
150
Model View Intent - An Introduction
Jossi Wolf
August 16, 2017
Tweet
Share
More Decks by Jossi Wolf
See All by Jossi Wolf
Understanding Recomposition Performance Pitfalls
jossiwolf
3
240
DC SF - Hitchhiking Through Jetpack Compose
jossiwolf
2
360
[DC SF 2022] Hitchhiking through Jetpack Compose
jossiwolf
2
400
[Berlin 2021] Hitchhiker's Guide to Compose
jossiwolf
4
660
From LiveData to Coroutines & Flow - DevFest ZA
jossiwolf
2
180
From LiveData to Coroutines & Flow - Android Summit
jossiwolf
2
160
From LiveData to Coroutines & Flow
jossiwolf
1
690
Experimenting with the Kotlin Compiler
jossiwolf
0
370
From Java to Kotlin Multiplatform - DevFest Nuremberg
jossiwolf
0
120
Other Decks in Programming
See All in Programming
Amazon RDS 向けに提供されている MCP Server と仕組みを調べてみた/jawsug-okayama-2025-aurora-mcp
takahashiikki
1
110
Updates on MLS on Ruby (and maybe more)
sylph01
1
180
AIと私たちの学習の変化を考える - Claude Codeの学習モードを例に
azukiazusa1
10
4.4k
基礎から学ぶ大画面対応(Learning Large-Screen Support from the Ground Up)
tomoya0x00
0
3.2k
MCPとデザインシステムに立脚したデザインと実装の融合
yukukotani
4
1.4k
請來的 AI Agent 同事們在寫程式時,怎麼用 pytest 去除各種幻想與盲點
keitheis
0
120
私の後悔をAWS DMSで解決した話
hiramax
4
210
デザイナーが Androidエンジニアに 挑戦してみた
874wokiite
0
540
旅行プランAIエージェント開発の裏側
ippo012
2
920
ファインディ株式会社におけるMCP活用とサービス開発
starfish719
0
1.9k
Ruby×iOSアプリ開発 ~共に歩んだエコシステムの物語~
temoki
0
340
時間軸から考えるTerraformを使う理由と留意点
fufuhu
16
4.8k
Featured
See All Featured
[RailsConf 2023 Opening Keynote] The Magic of Rails
eileencodes
30
9.7k
I Don’t Have Time: Getting Over the Fear to Launch Your Podcast
jcasabona
33
2.4k
RailsConf & Balkan Ruby 2019: The Past, Present, and Future of Rails at GitHub
eileencodes
139
34k
Building an army of robots
kneath
306
46k
Code Reviewing Like a Champion
maltzj
525
40k
個人開発の失敗を避けるイケてる考え方 / tips for indie hackers
panda_program
113
20k
Building a Scalable Design System with Sketch
lauravandoore
462
33k
Automating Front-end Workflow
addyosmani
1370
200k
Why You Should Never Use an ORM
jnunemaker
PRO
59
9.5k
Side Projects
sachag
455
43k
Distributed Sagas: A Protocol for Coordinating Microservices
caitiem20
333
22k
Responsive Adventures: Dirty Tricks From The Dark Corners of Front-End
smashingmag
252
21k
Transcript
Model View Intent An Introduction
Jossi Wolf Android Developer About Me
MVI MVP MVC MVVM Redux Flux God-like Activities
Model View Intent
None
A B C data data Unidirectional Data Flow D data
data
A B C data data Unidirectional Data Flow D data
data
someModel.set(…) Immutability
someModel.set(…) Immutability
String calendar = "calendar"; System.out.println(calendar.toUpperCase()); // CALENDAR Pure Functions
public class SchoolsViewState { boolean loading; Throwable error; List<SchoolsModel> schools;
} State Model
Data Flow in MVI View Intents (User Actions) Business Logic
emits Presenter Model
public interface SchoolsViewPresenterContract { interface SchoolsViewActions { } interface SchoolsPresenterActions
{ } }
interface SchoolsPresenterActions { void loadSchools(); }
interface SchoolsViewActions { void showLoading(); void showSuccess(); void showError(); }
interface SchoolsViewActions { void render(SchoolsViewState state); }
public class SchoolsActivity implements SchoolsViewActions { @Override public void render(SchoolsViewState
state) { // The view decides how to render the state } }
@Override public void render(SchoolsViewState state) { if (state.getError() != null)
{ showError(state.getError().getMessage()); } if (state.isLoading()) { showLoader(); clearAdapter(); } else if (!state.isLoading()) { hideLoader(); } if (state.getSchools() != null) { showSchools(state.getSchools()); } }
public class ExampleStateModel { private boolean loading; private Throwable error;
private List<SchoolsModel> data; ExampleStateModel(boolean loading, Throwable error, List<SchoolsModel> data) { // set everything } }
public class ExampleStateModel { private boolean loading; private Throwable error;
private List<SchoolsModel> data; private ExampleStateModel( boolean loading, Throwable error, List<SchoolsModel> data) { // set everything } }
public static SchoolsViewState LoadingState() { return new SchoolsViewState(true, null, null);
} public static SchoolsViewState ErrorState(Throwable error) { return new SchoolsViewState(false, error, null); } public static SchoolsViewState DataLoadedState(List<SchoolsModel> schools) { return new SchoolsViewState(false, null, schools); }
State Reducer
HomeViewState { loading = false error = null data =
[…] }
HomeViewState { loading = false error = null data =
[a, b, c] } HomeViewState { loading = false error = null data = [x, y, z] } [a, b, c, x, y, z]
@Test public void loadSchoolsSuccessful() { when(api.getHamburgSchools()) .thenReturn(Observable.just(generateFakeList())); schoolsPresenter.loadSchools(); verify(schoolsView).render(SchoolsViewState.LoadingState()); verify(schoolsView).render(SchoolsViewState.DataLoadedState(generateFakeList()));
}
@Test public void loadSchoolsNotSuccessful() { Throwable throwable = new Throwable();
when(api.getHamburgSchools()) .thenReturn(Observable.error(throwable)); schoolsPresenter.loadSchools(); verify(schoolsView).render(SchoolsViewState.LoadingState()); verify(schoolsView).render(SchoolsViewState.ErrorState(throwable)); }
Predictability = = + ?
Predictability = = =
Predictability LoadingState DataLoadedState ErrorState
Readable Code Presenter View Interactor Database Network void a( )
void b( )
None
Reading on https://github.com/jossiwolf/MVI-Example https://www.youtube.com/watch?v=0IKHxjkgop4 http://hannesdorfmann.com/android/mosby3-mvi-1 https://github.com/oldergod/android-architecture
public MainViewState reduce(MainViewState previous, MainViewState next) { MainViewState computedViewState =
MainViewState.Companion.ErrorState(new Throwable("No State")); if (next.getLoading()) { computedViewState = MainViewState.Companion.LoadingState(); } else if (next.getError() != null) { computedViewState = MainViewState.Companion.ErrorState(next.getError()); } else if (next.getData() != null) { List<String> data = new ArrayList<>(); if (previous.getData() != null) { data.addAll(previous.getData()); } data.addAll(next.getData()); computedViewState = MainViewState.Companion.DataLoadedState(data); } return computedViewState; }