Building First Class Android Sdks

This talk is a summary of the learnings of building fabric.

Based on the original slides from Ty Smith. https://speakerdeck.com/tysmith/andevcon-2014-building-first-class-sdks

Transcript

1. Building First Class Android SDK January 15, 2015 #AndroidDevSdks
2. January 15, 2015 #AndroidDevSdks SDK PEPINO
3. Israel Ferrer Camacho Senior Software Engineer @rallat
8. Fabric Sample App Cannonball https://github.com/twitterdev
9. What means to be a First Class SDK?
10. Modular
12. ABOMINATION
13. Modularity Fabric.with(this, new Twitter()); Fabric.with(this, new TweetUi(), new TweetComposer());
14. Fabric.aar Cache Settings Concurrency Events Network Persistence
15. Fabric.aar Cache Settings Concurrency Events Network Persistence KitCore Kit Common Services
16. Fabric.aar Cache Settings Concurrency Events Network Persistence KitCore Kit A Kit C Kit B Features Kit Common Services
17. Fabric.aar Cache Settings Concurrency Events Network Persistence KitCore Kit A Kit C Kit B KitInterface Interface Features Kit Common Services
18. Fabric.aar Cache Settings Concurrency Events Network Persistence TwitterCore.aar TweetUi.aar Digits.aar TweetComposer.aar Twitter.aar Interface Features Kit Common Services
19. Extensible
20. Fabric fabric = new Fabric.Builder(this) .kits(new Crashlytics()) .initializationCallback( new Callback<Fabric>() { void success(Fabric fabric) { } void failure(Exception exception) { } }) .build(); Callbacks
21. Extensible Interfaces interface Logger { void d(String tag, String text, Throwable throwable); void v(String tag, String text, Throwable throwable); void i(String tag, String text, Throwable throwable); void w(String tag, String text, Throwable throwable); void e(String tag, String text, Throwable throwable); }
22. Sane Defaults public class DefaultLogger { public DefaultLogger(int logLevel) { this.logLevel = logLevel; } void d(String tag, String text, Throwable throwable) { if (isLoggable(tag, Log.DEBUG)) Log.d(tag, text, throwable); } ... }
23. Extensible Classes class MyApiClient extends TwitterApiClient { interface MyService { @GET(“/1.1/statuses/show.json”) Tweet getTweet(@Query(“id”) int id); } MyService getMyService() { return getService(MyService.class); } }
24. Extensible View Styles <style name="tw__TweetLightStyle"> <item name="tw__container_bg_color"> @color/tw__tweet_light_container_bg_color </item> <item name="tw__primary_text_color"> @color/tw__tweet_light_primary_text_color </item> <item name="tw__action_color"> @color/tw__tweet_action_color </item> </style>
25. Easy to Use Hard to Misuse
26. >[]+{} Javascript example
27. >[]+{} [Object object] Javascript example
29. >[]+{} [Object object] >{}+[] Javascript example
30. >[]+{} [Object object] >{}+[] 0 Javascript example
31. WAT
32. WAT
33. Crashlytics.start(this, 5); Crashlytics.setListener(createCrashlyticsListener()); Crashlytics.setPinningInfo(createPinningInfoProvider()) Crashlytics.getInstance().setDebugMode(true); Initialization
34. Crashlytics.setListener(createCrashlyticsListener()); Crashlytics.setPinningInfo(createPinningInfoProvider()); Crashlytics.getInstance().setDebugMode(true); Crashlytics.start(this, 5); Initialization
35. Crashlytics.start(this, delay, listener, pinningInfo, debugMode); Initialization
36. Crashlytics.start(this, 0, null, null, null, true); Initialization
37. Crashlytics crashlytics = new Crashlytics.Builder() .delay(1) .listener(createCrashlyticsListener()) .pinningInfo(createPinningInfoProvider()) .build(); Fabric.with(this, crashlytics); Fluent Pattern
38. Fabric.with(new Fabric.Builder(this) .kits(new Crashlytics()) .debuggable(true) .logger(new DefaultLogger(Log.VERBOSE)) .looper(getCustomLooper()) .executor(getCustomExecutorService()) .build()); Fluent Pattern
39. Adapter Pattern public class TweetViewFetchAdapter<T extends BaseTweetView> extends TweetViewAdapter<T> { … } public class TweetViewAdapter<T extends BaseTweetView> extends BaseAdapter { … }
40. Styling <?xml version="1.0" encoding="utf-8"?> <resources> <style name="CustomDigitsTheme" parent="android:Theme.Material.Light"> <item name="android:textColorPrimary"> @android:color/black</item> <item name="android:textColorSecondary"> @android:color/darker_gray</item> <item name="android:windowBackground"> @android:color/white</item> <item name="android:textColorLink">#ff398622</item> <item name="android:colorAccent">#ff398622</item> </style> </resources>
41. Intuitive method naming Digits.authenticate(new AuthCallback() { @Override public void success(DigitsSession session, String phoneNumber) { } @Override public void failure(DigitsException error) { } }); adapter.setTweetIds(tweetIds, new LoadCallback<>() {…});
42. Detecting Dependencies <manifest … package="com.example.SDK" > <application ... > … <meta-data android:value="11235813213455" 
 android:name=“com.fabric.ApiKey” /> </application> </manifest>
43. public static Fabric with(Context context) { Context appContext = context.getApplicationContext(); ApplicationInfo ai = context.getPackageManager() .getApplicationInfo(ac.getPackageName(),
 PackageManager.GET_META_DATA); String apiKey = ai.metaData.getString(API_KEY); return new Fabric(appContext, apiKey); } Detecting Dependencies
44. public static Fabric with(Context context) { Context appContext = context.getApplicationContext(); ApplicationInfo ai = context.getPackageManager() .getApplicationInfo(ac.getPackageName(),
 PackageManager.GET_META_DATA); String apiKey = ai.metaData.getString(API_KEY); return new Fabric(appContext, apiKey); } Detecting Dependencies
45. public TwitterApiClient { final Session session; public TwitterApiClient(Session session) { this.session = session; } public TwitterApiClient() { this.session = Twitter.getSessionManager().getActiveSession(); } } Detecting Dependencies
46. Minimizing Permissions
47. Minimizing Permissions <uses-permission android:name="android.permission.INTERNET"/>
48. Minimizing Permissions crashlytics.setUserEmail(“appuser@domain.com”);
49. Permissions Detection protected boolean canCheckNetworkState(Context context) { String permission = Manifest.permission.ACCESS_NETWORK_STATE; int result = context.checkCallingOrSelfPermission(permission); return (result == PackageManager.PERMISSION_GRANTED); }
50. Optional Features <manifest … package="com.example.SDK" > <application ... > … </application> <uses-feature android:name="android.hardware.camera" android:required=”false” /> </manifest>
51. Features Detection protected boolean hasCamera(Context context) { PackageManager pm = context.getPackageManager(); String camera = PackageManager.FEATURE_CAMERA; return pm.hasSystemFeature(camera); }
52. Android Version Detection if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.FROYO) { return formatID(Build.HARDWARE);
 } return null;
53. Intent Detection try { startActivityForResult(new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0); } catch (ActivityNotFoundException e){ }
54. Intent Detection PackageManager pm = context.getApplicationContext().getPackageManager(); List<ResolveInfo> activities = pm.queryIntentActivities( new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH),0); if (activities.size() > 0) { //an app exists that can recognize speech }
55. Classpath Detection private boolean hasOkHttpOnClasspath() { try { Class.forName("com.squareup.okhttp.OkHttpClient"); return true; } catch (ClassNotFoundException e) { } return false; } provided 'com.squareup.okhttp:okhttp:2.0.0'
56. Classpath Detection public class DefaultClient implements Client { private final Client client; public DefaultClient() { if (hasOkHttpOnClasspath()) { client = new OkClient(); } else { client = new UrlConnectionClient(); } } … }
57. Catch unexpected exceptions try { //Do all the things! } catch (Exception e){ //Log something meaningful }
58. Throw expected exceptions /** * Sets the {@link io.fabric.sdk.android.Logger} * @throws java.lang.IllegalArgumentException */ public Builder logger(Logger logger) { if (logger == null) { throw new IllegalArgumentException( "Logger must not be null."); } this.logger = logger; return this; }
59. Gracefully Degrade if (TextUtils.isEmpty(apiKey) if (debuggable){ throw new IllegalArgumentException(“apiKey is null!"); } else { Logger.e(…); return null; } }
60. Testable
61. Make it Testable/Mockable Avoid static methods
62. Make it Testable/Mockable Avoid static methods Avoid final classes and accessing fields directly
63. Make it Testable/Mockable Avoid static methods Avoid final classes and accessing fields directly Utilize interfaces around entry points
64. Make it Testable/Mockable Avoid static methods Avoid final classes and accessing fields directly Utilize interfaces around entry points Provide test package in separate artifact
65. Hard to Test package com.example; public final class Tweeter { private Network network; public static Tweeter getInstance() {...} private Tweeter() { this.network = new Network(); } public List<Tweet> getTweets() { return network.getTweets(); } }
66. Easy to Test package com.example; public final class Tweeter { private Network network; public static Tweeter getInstance() {...} private public Tweeter(Network network) { this.network = new Network() network; } public List<Tweet> getTweets() { return getNetwork().getTweets(); } … }
67. Using in Tests package com.example.Tweeter; public class MyTest extends AndroidTestCase { Tweeter tweeter; @Override public void setup() { tweeter = mock(Tweeter.class); } ... }
68. High-performance
69. Size
70. Size
71. 3rd Party Library Mindfulness
72. 3rd Party Library Mindfulness PROTOBUF KB
73. 3rd Party Library Mindfulness PROTOBUF KB OURS KB
74. How big are Fabric AARs? Fabric: 190kb Crashlytics: 90kb Beta: 13kb Answers: 20kb Twitter API & SSO: 296kb Tweet UI: 120kb Tweet Composer: 5kb Digits: 236kb
75. Reporting Binary Size task reportSdkFootprint << { def sdkProject = project(':clients:SdkProject') def nonSdkProject = project(':clients:NonSdkProject') def crashlyticsFootprint = getSizeDifference( new File("${sdkProject.buildDir}.../Sdk.apk"), new File("${nonSdkProject.buildDir}.../NonSdk.apk") ) println crashlyticsFootprint }
76. Dalvik Method Count >./gradlew assemble … Unable to execute dex: method ID not in [0, 
 0xffff]: 65536 Conversion to Dalvik format failed: Unable to 
 execute dex: method ID not in [0, 0xffff]: 65536
77. Dalvik Method Count > git clone git@github.com:mihaip/dex-method-counts.git > cd dex-method-counts > ant jar > ./dex-method-counts path/to/App.apk Read in 65490 method IDs. <root>: 65490 : 3 accessibilityservice: 6 bluetooth: 2 content: 248 pm: 22 res: 45 com: 53881 example: 283 sdk: 283
78. Minimize Network Usage 10X SMALLER 100X FASTER XML PROTOBUF
79. Batching Requests High Power Low Power Idle 24% 30% 63% 14% 70%
81. Modular
82. Modular Extensible
83. Modular Extensible Easy to Use Hard to Misuse
84. Modular Extensible Easy to Use Hard to Misuse Testable
85. Modular Extensible Easy to Use Hard to Misuse Testable High-performance
86. @wendi_ @lientm @tsmith Thanks
87. #AndroidDevSdks Questions?