DESIGNING FOR DEVELOPERS Ty Smith uber.github.io @tsmith 

Building for Developers Ty Smith uber.github.io @tsmith 

Overview — Developer Product Research — Developer Usability Focuses — Library Quality Standards — Best Practices for Releases — Managing Communities @tsmith 

Product Research @tsmith 

Standard product workflow @tsmith 

Developer Tool workflow @tsmith 

People Need Focus @tsmith | https://twitter.com/marcos_placona/status/882487720597237760 

Expertise Bias @tsmith 

Product's role in a developer world @tsmith 

Finding the right job for your product @tsmith | https://hbr.org/2016/09/know-your-customers-jobs-to-be-done 

Finding the right job for your product @tsmith | https://hbr.org/2016/09/know-your-customers-jobs-to-be-done 

Finding the right job for your product Crash Reporting -Stability -Time to build features -Insight into instability @tsmith | CC-BY-2.0 - Bill Ward | https://hbr.org/2016/09/know-your-customers-jobs-to-be-done 

Developer Customers @tsmith 

Developer Demographics @tsmith | Search Engine Guide 

Developer Personas Name Role Company Frank CS Student University Betty Founder Seed Startup João Engineer Emerging Market Series A Paul Product Manager Hypergrowth Series C Sharon Staff Engineer Public SV Company Hannah Consultant Enterprise Company @tsmith | https://wiki.mozilla.org/DeveloperExperience/Personas 

Developer Research — Watch them integrate — Dig into expectations — Survey @tsmith 

Success Objectives — Developer Productivity — Developer Happiness — Developer Trust @tsmith 

@tsmith 

Usability @tsmith | CC-BY-2.0 - Sherman Paggi 

Autodispose Automatic binding+disposal of RxJava 2 streams. @tsmith | https://github.com/uber/AutoDispose 

Easy to Integrate dependencies { implementation 'com.uber.autodispose:autodispose:x.y.z' } observable .doStuff() .as(autoDisposable(this)) //<--Here's the magic. .subscribe(s -> ...) @tsmith | https://github.com/uber/AutoDispose 

Concise observable .doStuff() .as(autoDisposable(this)) .subscribe(s -> ...) @tsmith | https://github.com/uber/AutoDispose 

Intuitive //-------------------Vanilla RXJava---------------- fun doStuff() { subcription = observable.doStuff().subscribe(s -> ...) } override fun onDestroy() = subscription.unsubscribe() //-------------------Autodispose------------------- observable.doStuff() .as(autoDisposable(this)) .subscribe(s -> ...) @tsmith | https://github.com/uber/AutoDispose 

Consistency public interface ScopeHandler { @CheckReturnValue Function, FlowableSubscribeProxy> forFlowable(); @CheckReturnValue Function, ObservableSubscribeProxy> forObservable(); @CheckReturnValue Function, MaybeSubscribeProxy> forMaybe(); @CheckReturnValue Function, SingleSubscribeProxy> forSingle(); @CheckReturnValue Function forCompletable(); } @tsmith | https://github.com/uber/AutoDispose 

Composition public interface ObservableSubscribeProxy { Disposable subscribe(); Disposable subscribe(Consumer onNext); ... TestObserver test(); ... } @tsmith | https://github.com/uber/AutoDispose 

Resilient and Defensive @Override public ObservableSubscribeProxy apply(final Observable upstream) { return new ObservableSubscribeProxy() { @Override public Disposable subscribe() { return new AutoDisposeObservable<>(upstream, scope).subscribe(); } ... }; } @tsmith | https://github.com/uber/AutoDispose 

Flexibility public interface LifecycleScopeProvider { Observable lifecycle(); Function correspondingEvents(); E peekLifecycle(); } @tsmith | https://github.com/uber/AutoDispose 

Flexibility dependencies { implementation 'com.uber.autodispose:autodispose-android:x.y.z' implementation 'com.uber.autodispose:autodispose-android-archcomponents:x.y.z' implementation 'com.uber.autodispose:autodispose-kotlin:x.y.z' implementation 'com.uber.autodispose:autodispose-rxlifecycle:x.y.z' } @tsmith | https://github.com/uber/AutoDispose 

Testability dependencies { implementation 'com.uber.autodispose:autodispose-android-archcomponents:x.y.z' testImplementation 'com.uber.autodispose:autodispose-android-archcomponents-test:x.y.z' } TestLifecycleOwner lifecycle = TestLifecycleOwner.create(); subject.as(autoDisposable(from(lifecycle))).subscribe(o); lifecycle.emit(Lifecycle.Event.ON_CREATE); ... lifecycle.emit(Lifecycle.Event.ON_DESTROY); subject.onNext(1); o.assertNoMoreEvents(); @tsmith | https://github.com/uber/AutoDispose 

Debugability public final class AutoDisposePlugins { public static void lockdown() { lockdown = true; } public static void setOutsideLifecycleHandler( @Nullable Consumer handler) { if (lockdown) { throw new IllegalStateException("Plugins can't be changed anymore"); } outsideLifecycleHandler = handler; } } @tsmith | https://github.com/uber/AutoDispose 

Documentation /** * Entry point for auto-disposing streams from a {@link ScopeProvider}. *

* Example usage: *

* Observable.just(1)
* .as(AutoDispose.autoDisposable(scope))
* .subscribe(...)
* 

* * @param provider the target scope provider * @param the stream type. * @return an {@link AutoDisposeConverter} to transform with operators like * {@link Observable#as(ObservableConverter)} */ public static AutoDisposeConverter autoDisposable(final ScopeProvider provider) {...} @tsmith | https://github.com/uber/AutoDispose 

Example Code @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Using automatic disposal, this should determine that the correct time to // dispose is onDestroy (the opposite of onCreate). Observable.interval(1, TimeUnit.SECONDS) .doOnDispose((value) -> { Log.i(TAG, "Disposing subscription from onCreate()")) }) .as(autoDisposable(from(this))) .subscribe((value) -> { Log.i(TAG, "Started in onCreate(), running until onDestroy(): " + num); }); } @tsmith | https://github.com/uber/AutoDispose 

@tsmith 

Quality Primum non nocere @tsmith 

Quality Stability @tsmith 

Performance @tsmith 

Size @tsmith| source: https://www.youtube.com/watch?v=CVQ8cg_WIwY 

Data usage @tsmith 

Transitive Dependencies @tsmith 

@tsmith 

Releases @tsmith 

Semantic Versioning - X.Y.Z Decimal Use Example X - Major API Change Changed Public Method Name Y _ Minor Feature Added New Functionality Z - Patch Fix Fixed Crash @tsmith 

Changelogs @tsmith 

Deprecation — Be thoughtful about introducing new APIs — Respect semantic versioning — Mark methods as deprecated — Set expected timeline or version for removal — Incentivize updates @tsmith 

Deprecation /** * Extension that proxies to [Observable.as] + [AutoDispose.autoDisposable] */ @Deprecated( level = ERROR, message = "Replaced with autoDisposable() to match top level APIs.", replaceWith = ReplaceWith("autoDisposable(scope)", "com.uber.autodispose.kotlin.autoDisposable") ) @CheckReturnValue inline fun Observable.autoDisposeWith(scope: Maybe<*>): ObservableSubscribeProxy = this.`as`(AutoDispose.autoDisposable(scope)) @tsmith | https://github.com/uber/AutoDispose 

Community @tsmith | CC-BY-4.0 - Billie Grace Ward | http://uk.droidcon.com/skillscasts/11019-open-source-and-building-communities 

Issues @tsmith 

Contributors @tsmith 

Wrap up — Developer Product Research — Developer Usability Focuses — Library Quality Standards — Best practices for Releases — Managing Communities @tsmith 

BUILDING FOR DEVELOPERS Ty Smith uber.github.io @tsmith