Building Top-Notch Androids SDKs

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. Reasons
• Developers are lazy - reuse code
• Separate concerns (build independent blocs)
• Write better software
• Speed up compile time
• Make other people happy…

8. Make it open source!
• 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!

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. Create a SDK!
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

13. Managing Releases
Use the library in a real project
Master
SDK as a git submodule
Master
Develop
Develop
Feature Branch
Feature Branch

14. Agenda
1. Why?
2. How?
3. What?

15. Great SDK Qualities
• Available
• Easy to use
• Flexible
• Testable
• Performant
• Reliable
• Lightweight

16. Available
build.gradle
dependencies {
include ‘io.relayr:android-sdk:0.0.5’
}
*gradle-mvn-push.gradle by Chris Banes

17. Easy to use
• Intuitive
• Consistent
• Easy to use, hard to misuse

18. Easy to use
• Easy to initialise
RelayrSdk.init(this);
• Easy to use
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. Flexible - be context aware
mApplication.registerActivityLifecycleCallbacks(
new Application.ActivityLifecycleCallbacks() {
@Override
public void onActivityResumed(Activity activity) {
// we know there’s a UI!
}
}
);

25. Testable
• Mock mode (no network requests)
• No static methods
• Avoid final classes
• Avoid access to fields directly

26. Performant
• Don’t block the current thread!
RelayrSdk.sendMessage(“At droidcon Krakow!”);

27. Performant - Don’t log in production
• With Code
RelayrSdk.Builder(this)
.setDebuggable(false)
.build();
• On the Manifest
debuggable=false

28. Reliable
• Don’t crash silently - inform the user when a
problem occurs
RelayrSdk.login(new LoginCallback() {
public void onSuccess() {
// sign the user into the app
}
public void onError() {
// show error message
}
});

29. Lightweight
• Poor network conditions
• Association between small and fast
• Reluctance to include large libraries

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