Building Top-Notch SDKs - Droidcon Krakow

The Android app ecosystem is growing and it's time to make it easier for developers to build better apps. There is a need for better tools and libraries to make everyday's work more efficient. This talk aims to create a minimum viable SDK. A set of best practices, tips and tricks learnt whilst building the relayr SDK [dev.relayr.io] for accessing real world sensor data from the WunderBar, in a step-by-step approach to show you how it should look like and let you focus on the functionality you want to provide.

Transcript

1. Building Top-Notch Android SDKs Hugo Doménech @hudomju
2. relayr bring things to life
3. relayr bring things to life easy tools to connect things and apps
4. Building Top-Notch Android SDKs Hugo Doménech @hudomju
5. Agenda 1. Why? 2. How? 3. What?
6. Agenda 1. Why? 2. How? 3. What?
7. • Developers are lazy - reuse code • Separate concerns (build independent blocs) • Write better software • Speed up compile time • Make other people happy… Reasons
8. • Feel better • Code better: Power of shame • Get features and bug fixes for free • Easier to sell - quality prove • Excitement from the community • Security • It’s free • But most important: Be famous! Make it open source!
9. Agenda 1. Why? 2. How? 3. What?
10. Decide what you are providing Library Project jar (Java ARchive) Apk Lib aar (Android Archive Resource)
11. Let’s build a SDK!
12. 1. Don’t start with code: README.md and ROADMAP.md 2. Put it in a Git Repository 3. Include it in your CI (Continuous Integration) 4. Add static code analysis tools (i.e. FindBugs, Lint) 5. Autogenerate documentation (i.e. JavaDoc) 6. Prepare for testing 7. Make it accessible (i.e. distribute via maven) 8. Add a sample project Create a SDK!
13. Managing Releases Use the library in a real project SDK as a git submodule Master Master Develop Develop Feature Branch Feature Branch
14. Agenda 1. Why? 2. How? 3. What?
15. • Available • Easy to use • Flexible • Testable • Performant • Reliable • Lightweight Great SDK Qualities
16. Available dependencies { include ‘io.relayr:android-sdk:0.0.5’ } build.gradle *gradle-mvn-push.gradle by Chris Banes
17. • Intuitive • Consistent • Easy to use, hard to misuse Easy to use
18. • Easy to initialise • Easy to use Easy to use RelayrSdk.init(this); RelayrSdk.logMessage(“At droidcon Krakow!”);
19. Flexible new RelayrSdk.Builder(this) .inMockMode(true) .apiEndpoint(“api.relayr.io”) .withDebugger(new DefaultDebugger()) .build();
20. Flexible - minimize permisions
21. Flexible - minimize permisions public boolean canVibrate() { String permission = "android.permission.VIBRATE"; int result = mContext.checkCallingOrSelfPermission(permission); return result == PackageManager.PERMISSION_GRANTED; }
22. Flexible - minimize requisites <uses-permission android:name="android.permission.BLUETOOTH"/> <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/> <uses-feature android:name=“android.hardware.bluetooth_le" android:required="false"/> public boolean isBleSupported() { String feature = PackageManager.FEATURE_BLUETOOTH_LE; return getPackageManager().hasSystemFeature(feature); }
23. Flexible - support different versions defaultConfig { applicationId 'io.relayr.wunderbar' minSdkVersion 15 targetSdkVersion 21 versionCode 22 versionName '1.0.22' } public boolean isSdk18() { return android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2; }
24. mApplication.registerActivityLifecycleCallbacks( new Application.ActivityLifecycleCallbacks() { @Override public void onActivityResumed(Activity activity) { // we know there’s a UI! } } ); Flexible - be context aware
25. • Mock mode (no network requests) • No static methods • Avoid final classes • Avoid access to fields directly Testable
26. • Don’t block the current thread! Performant RelayrSdk.sendMessage(“At droidcon Krakow!”);
27. • With Code Performant - Don’t log in production RelayrSdk.Builder(this) .setDebuggable(false) .build(); debuggable=false • On the Manifest
28. • Don’t crash silently - inform the user when a problem occurs Reliable RelayrSdk.login(new LoginCallback() { public void onSuccess() { // sign the user into the app } public void onError() { // show error message } });
29. • Poor network conditions • Association between small and fast • Reluctance to include large libraries Lightweight
30. Lightweight - don’t require libraries private boolean hasOkHttpOnClasspath() { try { Class.forName("com.squareup.okhttp.OkHttpClient"); return true; } catch (ClassNotFoundException e) { } return false; } dependencies { provided ‘com.squareup.okhttp:okhttp:2.0.0’ }
31. Lightweight - be modular dependencies { } include ‘io.relayr:java-sdk:0.0.5’ include ‘io.relayr:android-sdk:0.0.5’ include ‘io.relayr:android-onboarding:0.0.7’ include ‘io.relayr:master-module:1.2.0’ include ‘io.relayr:android-commons:1.0.0’
32. Recapitulate 1. Why? 2. How? 3. What?
33. Take away
34. Questions? Hugo Doménech @hudomju