CODEWITHSUNDEEP
android
Boardy
Boardy

Reputation: 36205

Create a JAR for Android Library Distribution

I am working on an android library, and wish to export a JAR file that I can distribute for others to use in their apps. I don't want to distribute the source code as it contains details on posting to my web server.

I have tried using the JAR file that is created in the bin directory and copying the jar file to my project and referencing it within my project and ticking the export button.

When I try and run my project referencing the library that I've copied, my app throws an exception with NoClassDefFoundError. I've done some Googling and everything I have found suggests you have to provide the source code and let the user import into their IDE and then reference that project into their app which I don't want to do. It must be possible as other companies provide JAR files for libraries that can be included.

Thanks for your help.

Upvotes: 3

Views: 607

Answers (2)

CommonsWare
CommonsWare

Reputation: 1006654

I don't want to distribute the source code as it contains details on posting to my web server.

Bear in mind that anyone who wants to can get that data out of the JAR.

It must be possible as other companies provide JAR files for libraries that can be included.

AFAIK, this recipe still works:

  1. Create an Android library project, with your source code, resources, and such, and get it working

  2. Compile the Java source (e.g., via Ant) and turn it into a JAR file

  3. Create a copy of your original Android library project to serve as a distribution Android library project

  4. Place the compiled JAR from step #2 and put it in libs/ of the distribution library project from step #3.

  5. Delete everything in src/ of the distribution library project (but leave the now-empty src/ directory there)

  6. Distribute the distribution library project (e.g., ZIP it up)

This effectively gives you what you see with the Play Services SDK -- a library project with no source code, but instead a JAR in libs/, along with the resources and such.

I will be reconfiming this recipe tomorrow and will try to remember to update this answer if I find that it needs adjusting for the current crop of tools.

And the new Gradle-based build system supports the AAR package for distributing libraries and such, though I have not played with this yet.

UPDATE

This recipe works, so long as the library project does not itself have dependencies upon another JAR or library project. In those cases, things seem to get messed up in the build process -- everything can compile, but class references from the dependencies cannot be resolved at runtime.

Upvotes: 6

Ercan
Ercan

Reputation: 3705

Did you try putting your jar file in libs folder?And if you are exporting a jar library for android be sure it has no /res folder. As you know you can't reference to your res folder from a jar therefore you have to use library project to reference your res folder (drawable,xml,ect...)On the other hand you cant make your code safe (the part you say about posting to your web service) by using it as jar since it is so easy to retrieve by reverse engineering. you better use some encoding (like base64 or any algorithm that bouncycastle provides)

Upvotes: 0

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