Aug 29, 2017

8 min read

Open Source Your Android Code — The Complete Guide

ADA | Adam Deconstructs Android

9/17/17 Update: JitPack.io appears to be a fast and easy alternative to open source Android code vs. the method below by integrating directly with GitHub. I have not tested JitPack so please share your feedback in the comments if you’ve implemented it.

You’ve spent hours building cool shit. What’s the next step? By open sourcing your work you’ll (hopefully) provide valuable code to the Android community, receive constructive feedback, and collaborate on building something better than what you originally had.

The current state of open sourcing for Android is unintuitive, involving integrating multiple services, waiting for manual approvals, and before this post, spending hours Googling obscure steps. That’s why I created a beginning-to-end guide to expedite the process.

The more open sourced code, the better.

Implementation

I will walk through each step of how I open sourced a CustomRippleView library for Android.

Place code inside an Android Archive Library (AAR) — Step 1 of 6

Besides open sourcing, AARs are useful when building multiple apps or versions with the same components.

About

Structurally the same as an Android app module
Includes source code, resource files, manifest (unlike JAR)
Compiles into Android Archive (AAR) rather than into APK
Post to some maven repository where devs can pull it as a dependency through Gradle (can also convert an app to a module)
Code Overlap — The app module will take precedence over a library if a resource ID is defined in both, library defined first will take precedence between libraries.

Implementation

If you’re creating a standalone library outside an existing app you’ll want to both create a new project to host the library module as well as test the library module in an existing app.

1. Build the open sourced library module in an existing project so that you can test the code as you go.

a) Create library module

Click the plus or File > New > Module > Android Library > provide unique Library Module Name (customrippleview)

b) Ensure local library module shows in project and compile local library in the app module.

settings.gradle

include ':app', ':customrippleview'

build.gradle (app module)

compile project(":customrippleview")

Add tools:replace=”android:name” to the app module’s Manifest file.

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest ...>    ...    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        android:name="..."
        tools:replace="android:name">
        ...
    </application>

</manifest>

2. Create a new Android project to host the open source code by itself so that it can be uploaded to bintray

Create the default app module with app following the name (customrippleviewapp) to differentiate the app module name from the open source library module we’ll create in the next step.

Application name: CustomRippleViewApp
Company domain: com.ebay.customrippleviewapp (needs to be a domain you own in order to get approved for open sourcing)
Package name: com.ebay.customrippleviewapp

3. Add your library module (refer to step 1A above)

4. Place the open source code inside new library module created

5. Remove original app module

Right-click on app module > Open Module Settings > remove original app module.

6. Choose resources to make public (Optional)

All resources default to public: By declaring at least one resource public it makes the rest private

res > values > public.xml

<resources><public name="mylib_app_name" type="string"/><public name="mylib_public_string" type="string"/></resources>

Publish library publicly on GitHub with licensing and Docs — Step 2 of 6

Apache License 2.0 is one of the most popular, similar to the MIT License, but provides grant of patent rights from contributors to users. Apache 2.0 is commonly found in Android, Apache, and Swift.

In terminal

git init

Make sure library module (customrippleview/) and build.gradle are not in the ignore list list and edit .gitignore to only contain library module files added.

git add .git commit -m "Custom Ripple View"git remote add origin git@github.com:AdamSHurwitz/CustomRippleView.gitgit push -u origin master

Bintray and Sonatype Setup — Step 3 of 6

You only need to go through this painful steps once to setup your bintray account. Praise the lord! As this isn’t difficult, but the most annoying step.

Bintray Implementation

1. Create bintray account

2. Create new repository

a) Add New Repository → Type: Maven → Default Licenses: Apache 2.0

b) Use lowercase naming convention: customrippleview

3. Enable auto signing

Enter Repository → Edit → General Settings → select GPG sign uploaded files automatically

a) Generate keys (Only done once for bintray account)

In terminal for project:

gpg --gen-key

Fill in Real name, Email address, and passphrase. If command does not work, run following command to install gpg and retry the command above.

brew install gnupg gnupg2

View keys created

gpg --list-keys

Expected Output:

pub   rsa2048 2017-05-21 [SC] [expires: 2019-05-21]
      public_key_generated_here
uid           [ultimate] Adam Hurwitz <yourEmail@gmail.com>
sub   rsa2048 2017-05-21 [E] [expires: 2019-05-21]

b) Upload keys

Upload the public key to keyservers. Call the following command and replace PUBLIC_KEY_ID with value after 2048 in the pub line.

gpg --keyserver hkp://pool.sks-keyservers.net --send-keys public_key_goes_here

Export both public and private key.

gpg -a --export yourEmail@gmail.com > public_key_sender.ascgpg -a --export-secret-key yourEmail@gmail.com > private_key_sender.asc

Enter your passphrase when prompted for private key.

View keys

less public_key_sender.ascless private_key_sender.asc

Copy and paste public and private keys into bintray: Under profile Edit > GPG Signing. Make sure to copy and paste from beginning and end tags or else bintray will not accept the keys.

-----BEGIN PGP PRIVATE/PUBLIC KEY BLOCK-----
...
key code is here...-----END PGP PRIVATE/PUBLIC KEY BLOCK-----

Sonatype Implementation

This step requires filling a Jira ticket. If you thought you could escape Jira in your free coding time, you’re mistaken. It’s not too bad, as both times I’ve submitted a ticket they’ve approved it within the same day.

¯\_(ツ)_/¯

1. Create Sonatype account

2. Create an a New Project request

Project: Community Support — Open Source Project Repository Hosting
Issue Type: New Project
Summary: Custom Ripple View For Android
Group Id: com.ebay.customrippleview
Project URL: https://github.com/eBay/CustomRippleView
SCM URL: https://github.com/eBay/CustomRippleView.git

3. Provide bintray your Sonatype OSS username

In your bintray profile Edit > Accounts > Sonatype OSS User: _____________

Prepare Project for Upload — Step 4 of 6

Prepare Library Module With Bintray

1. Add Jcenter and Maven dependency

Add to project’s build.gradle (not app or library build.gradle)

build.gradle

2. Define your bintray username, api key, and GPG Passphrase.

This info should be secure, which is why we’re adding it to local.properties which should not be tracked in GitHub as it is commonly ignored at the start of an Android project in the .gitignore file.

local.properties

bintray.user=YOUR_BINTRAY_USERNAME
bintray.apikey=YOUR_BINTRAY_API_KEY
bintray.gpg.password=YOUR_GPG_PASSPHRASE

3. Add repository information and build scripts

Update library’s build.gradle with repository information and add scripts for building library files and uploading the built files to bintray.

build.gradle

4. If using Kotlin in your code, disable Javadocs in library’s build.gradle

tasks.withType(Javadoc).all {
    enabled = false
}

Upload to jcenter— Step 5 of 6

Why is jcenter better than maven central?

Delivers library through CDN → faster loading
Largest Java Repository on earth
“Friendly” UI (perhaps in comparison)

Implementation

1. Upload to bintray/jcenter (Once Sonatype Open Source Project Repository Hosting request is approved)

./gradlew install

Expected Result: BUILD SUCCESSFUL

./gradlew bintrayUpload

Expected Result: BUILD SUCCESSFUL

Troubleshooting

I kept getting the BUILD FAILED response when attempting to upload. After many hours cursing at my terminal I realized even with this message, the package was being uploaded, so check the bintray package UI.

2. Sync to Jcenter for easy one line implementation in Android

Approval took ~3 hrs — How is this not automated too?!

ᕙ(⇀‸↼)ᕗ

a) Under the uploaded package settings select Add to JCenter

b) Select Host my snapshot…, fill in group id for package, and Select Send

Once approved, you’ll receive an email.

In the meantime you can check by searching on bintray which will also show when your package is hosted.

Type ‘http://jcenter.bintray.com/’ into a browser and the package path after the ‘/’.

ie: ‘com/ebay/customrippleview/customrippleview/1.0/’

3. Maintaining library

Linking to jcenter only needs to be done once. Moving forward, any package changes (updates, deletes), will be reflected in jcenter 2–3 min later.

Updates: Change the libraryVersion in library module and re-upload using Step 5, part 1.
Deleting: Remove each version from bintray before removing the entire package.

Use In Project — Step 6 of 6

Declare the library in gradle and call the desired files.

build.gradle (app module)

Group_Id —com.ebay.customrippleview (package name followed by group name)
Artifact_Id: customrippleview
Version: 1.0

compile 'com.ebay.customrippleview:customrippleview:1.0'

layout.xml

Resources

JitPack.io — JitPack is an Android specific open sourcing solution that appears to work seamlessly with GitHub repositories. For a premium, JitPack also provides private library hosting. I haven’t given it a try, but thanks to Rakshak and Vikarti for calling it out in the comments below!
The Cheese Factory Blog — How to distribute your own Android library through jCenter and Maven Central from Android Studio. BIG thanks! There were details that changed since this was published in 2015, but it was a great place to start.
Android Studio — Create an Android Library
bintray
sonatype
sonatype — request to host new open source project (only works when logged in to sonatype)
bintray documentation — Including your Package in JCenter
CustomRippleView GitHub sample and JCenter hosting

I’m Adam Hurwitz — hit the clapping hands icon and check out the rest of my writing if you enjoyed the above | Thanks!

Open Source Your Android Code — The Complete Guide

ADA | Adam Deconstructs Android

Implementation

Place code inside an Android Archive Library (AAR) — Step 1 of 6

About

Implementation

Publish library publicly on GitHub with licensing and Docs — Step 2 of 6

Bintray and Sonatype Setup — Step 3 of 6

Bintray Implementation

Sonatype Implementation

Prepare Project for Upload — Step 4 of 6

Prepare Library Module With Bintray

Upload to jcenter— Step 5 of 6

Why is jcenter better than maven central?

Implementation

Use In Project — Step 6 of 6

Resources

More from AndroidPub

Get the Medium app

Adam Hurwitz