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
Async Android
Search
Jamie McDonald
June 18, 2015
Programming
10
670
Async Android
NYC Android Developers Meetup, June 2015
Jamie McDonald
June 18, 2015
Tweet
Share
More Decks by Jamie McDonald
See All by Jamie McDonald
6 lessons learned scaling mobile
jdamcd
1
340
Android Engineering for Scale
jdamcd
13
2.2k
Other Decks in Programming
See All in Programming
try-catchを使わないエラーハンドリング!? PHPでResult型の考え方を取り入れてみよう
kajitack
3
290
TypeScript を活かしてデザインシステム MCP を作る / #tskaigi_after_night
izumin5210
4
470
從零到一:搭建你的第一個 Observability 平台
blueswen
0
220
Devinで実践する!AIエージェントと協働する開発組織の作り方
masahiro_nishimi
6
2.5k
REST API設計の実践 – ベストプラクティスとその落とし穴
kentaroutakeda
2
310
MLOps Japan 勉強会 #52 - 特徴量を言語を越えて一貫して管理する, 『特徴量ドリブン』な MLOps の実現への試み
taniiicom
2
570
CRUD から CQRS へ ~ 分離が可能にする柔軟性
tkawae
0
220
Parallel::Pipesの紹介
skaji
2
870
JVM の仕組みを理解して PHP で実装してみよう
m3m0r7
PRO
1
250
バランスを見極めよう!実装の意味を明示するための型定義 TSKaigi 2025 Day2 (5/24)
whatasoda
2
770
Use Perl as Better Shell Script
karupanerura
0
650
人には人それぞれのサービス層がある
shimabox
3
460
Featured
See All Featured
ピンチをチャンスに:未来をつくるプロダクトロードマップ #pmconf2020
aki_iinuma
123
52k
Fight the Zombie Pattern Library - RWD Summit 2016
marcelosomers
233
17k
Creating an realtime collaboration tool: Agile Flush - .NET Oxford
marcduiker
30
2.1k
Art, The Web, and Tiny UX
lynnandtonic
298
21k
The Web Performance Landscape in 2024 [PerfNow 2024]
tammyeverts
5
620
Being A Developer After 40
akosma
91
590k
StorybookのUI Testing Handbookを読んだ
zakiyama
30
5.8k
Adopting Sorbet at Scale
ufuk
76
9.4k
Bash Introduction
62gerente
614
210k
Designing Dashboards & Data Visualisations in Web Apps
destraynor
231
53k
Understanding Cognitive Biases in Performance Measurement
bluesmoon
29
1.7k
CoffeeScript is Beautiful & I Never Want to Write Plain JavaScript Again
sstephenson
160
15k
Transcript
None
Async Android Jamie McDonald
@Override public void onCreate() { super.onCreate(); Log.i(TAG, “Hi from the
main thread!”); } Main Thread title, date, 01 of 10
ANR title, date, 01 of 10
ANR title, date, 01 of 10 I/Choreographer﹕ Skipped 480 frames!
The application may be doing too much work on its main thread.
@UiThread public void updateUi(String title) { textView.setText(title); } @WorkerThread public
void showTitle() { textView.setText(SlowStuff.loadTitle()); } Tools title, date, 01 of 10
@UiThread public void updateUi(String title) { textView.setText(title); } @WorkerThread public
void showTitle() { textView.setText(SlowStuff.loadTitle()); } Tools title, date, 01 of 10
new Thread() { public void run() { final String result
= SlowStuff.blocking(); new Handler().post(new Runnable() { @Override public void run() { updateUi(result); } }); } }.start(); Thread title, date, 01 of 10
class LooperThread extends Thread { private Handler handler; public void
run() { Looper.prepare(); handler = new Handler() { public void handleMessage(Message msg) { // Process messages here } }; Looper.loop(); } } Looper title, date, 01 of 10
IntentService title, date, 01 of 10 public class BackgroundService extends
IntentService { public BackgroundService() { super("BackgroundWork"); } @Override protected void onHandleIntent(Intent intent) { SlowStuff.blocking(); } } startService(new Intent(this, BackgroundService.class));
new AsyncTask<Void, Void, String>() { @Override protected String doInBackground(Void... params)
{ return SlowStuff.blocking(); } @Override protected void onPostExecute(String s) { updateUi(s); } }.execute(); AsyncTask title, date, 01 of 10
title, date, 01 of 10 “Painless threading” - The year
2009
new AsyncTask<Void, Void, Result>() { [...] @Override protected void onPostExecute(Result
result) { if (result.isSuccess()) { doNextAsyncStep(result.getValue()); } else { // ??? } } }.execute(); Callback Hell title, date, 01 of 10
Execution Order title, date, 01 of 10 SERIAL SERIAL THREAD
POOL
class DataLoader extends AsyncTaskLoader<String> { public BackgroundLoader(Context context) { super(context);
} @Override protected void onStartLoading() { forceLoad(); } @Override public String loadInBackground() { return SlowStuff.blocking(); } } Loader title, date, 01 of 10
getLoaderManager().initLoader(LOADER_ID, null, new LoaderManager.LoaderCallbacks<String>() { @Override public Loader<String> onCreateLoader(int id,
Bundle args) { return new DataLoader(MainActivity.this); } @Override public void onLoadFinished(Loader<String> loader, String text) { updateUi(text); } @Override public void onLoaderReset(Loader<String> loader) { loader.reset(); } }); Loader title, date, 01 of 10
Enter RxJava!
RxJava title, date, 01 of 10 “RxJava tries to be
very lightweight. [...] focused on just the Observable abstraction and related higher-order functions”
Observer Pattern title, date, 01 of 10
Streams title, date, 01 of 10
public Observable<String> observable() { return Observable.create((subscriber) -> { subscriber.onNext(blocking()); subscriber.onCompleted();
}); } Observable title, date, 01 of 10
class MySubscriber extends DefaultSubscriber<String> { @Override public void onNext(String text)
{ updateUi(text); } @Override public void onError(Throwable e) { displayError(e); } } Subscriber title, date, 01 of 10
SlowStuff.observable() .subscribeOn(Schedulers.io()) .observeOn(AndroidSchedulers.mainThread()) .subscribe(new MySubscriber()); Schedulers title, date, 01 of
10
title, date, 01 of 10 Thread IntentService AsyncTask Loader RxJava
Main thread callbacks Configuration changes Error handling Composability Flexible scheduling
Operators title, date, 01 of 10 flatMap map filter doOnNext
onErrorResumeNext distinct cache zip retry ...
FlatMap title, date, 01 of 10
trackOps.loadWaveformUrl(urn) .flatMap(url -> imageOps.renderWaveform(url)) .onErrorResumeNext(imageOps.defaultWaveform()) [...] .subscribe(new WaveformSubscriber()); FlatMap title,
date, 01 of 10
OnErrorResumeNext title, date, 01 of 10
public final class EventQueue { static final Queue<StateTransition> PLAYBACK_STATE; static
final Queue<ProgressEvent> PLAYBACK_PROGRESS; static final Queue<PlayableEvent> PLAYABLE_CHANGED; [...] } Event Bus title, date, 01 of 10
None
title, date, 01 of 10
Subtitle title, date, 01 of 10 eventBus.queue(EventQueue.PLAYABLE_CHANGE) .filter(PlayableEvent.IS_TRACK_FILTER) .doOnNext(updateLikeCount) .observeOn(AndroidSchedulers.mainThread())
Only listen to interesting events
Subtitle Respond to state without storing it title, date, 01
of 10 Observable.combineLatest( eventBus.queue(EventQueue.PLAY_QUEUE_TRACK), eventBus.queue(EventQueue.PLAYER_UI), combineStates) .doOnNext(setTrackHasBeenSeen)
Downsides title, date, 01 of 10 Debugging Testing long call
chains Learning curve Boilerplate Config changes Backpressure Where & when to use it?
*£#%@£$?? title, date, 01 of 10
More title, date, 01 of 10 RxAndroid Not RxAndroid Retrofit
Retrolambda
soundcloud.com/jobs Thank you, NYC!