5 Steps To Clean Your Android Code

+Frankie Sardo

Enchant me.Simplify my life.

Make me amazing.

Android UI Design Principles

Android Software Design Principles

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Clean Code is UX for Software

#1

Model Objects

Automatic mapping is tempting

Keep you objects in shapeclass Event { private final String name; private final Location where; private final DateRange duration; private final Type type;

public Event(String name, Location where, DateRange when, Type type) { this.name = name; this.where = where; this.duration = when; this.type = type; if (name.isEmpty()) { throw new IllegalArgumentException("Event name is empty"); } if (type == WORKSHOP && when.includes(27TH_MARCH )) { throw new IllegalArgumentException("Workshops are scheduled after 27th of March"); } }

public boolean clashesWith(Event otherEvent) { return duration.overlaps(otherEvent.duration) && where.equals(otherEvent.where); }}

#2

External Services

Responses are unpredictable

Abstract over external APIs

#3

Business Logic

Concurrency is hard

Define your user storiesclass SearchRepositoriesScenario implements Scenario {

final SearchRepositoriesPresentation presentation; final GithubApi githubApi; final SearchRepositoriesRequest request; final Database database;

public SearchRepositoriesScenario(...) { ... }

public void run() { presentation.showLoading(); String keyword = request.getKeyword(); Repositories repositories = githubApi.searchRepositories(keyword); SearchRepositoriesResponse response = from(repositories); database.persist(response); presentation.updateList(response); presentation.hideLoading(); }

}

Keep modules loosely coupled

#4

Boilerplate code

Android code is verbose

Say what you meanclass SearchRepositoriesActivity extends ListActivity {

@Inject SearchRepositoriesController controller; @Icicle String query; // github.com/frankiesardo/icepick

protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); handleIntent(getIntent()); controller.displaySearch(query); }

protected void onNewIntent(Intent intent) { super.onNewIntent(intent); handleIntent(intent); }

private void handleIntent(Intent intent) { if (Intent.ACTION_SEARCH.equals(intent.getAction())) { query = intent.getStringExtra(SearchManager.QUERY); controller.startSearch(query); } } public boolean onCreateOptionsMenu(Menu menu) { return MenuHelper.inflate(getMenuInflater()).search() .up(ParentActivity.class).help().into(menu); }}

#5

Unit test

Tests constrain your design

Practice makes perfect

Q&A Time

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