Multiple Android Application Package .apk files from single source code

I would like an Android build system procedure, command line or Eclipse, to generate several .apk files from a single source codebase. Some common reasons for this - having specific versions for markets with different requirements or a free and paid version.

This question IS NOT ABOUT:

• Packaging shared code into Android libraries or into external Java jars

• Producing a debug vs. signed release .apk

Google says "you probably need to create separate Android projects for each APK you intend to publish so that you can appropriately develop them separately. You can do this by simply duplicating your existing project and give it a new name." Then they kindly suggest using libraries, which I understand. Then, they mention in passing exactly what I do want: "a build system that can output different resources based on the build configuration"

• I know that to accomplish conditional compilation in JAVA one can key off a 'public static final' variable. There is an example of tweaking such a value in build.xml. Any more complete example of an Android Ant build configuration for this or a link to an OSS project doing that now, please? BTW, build.xml is auto-generated, but I have seen people hacking it, so how does that work?

• With the package name declared in Manifest.xml as package="com.example.appname", if one needs to emit multiple .apks that vary that name, is one stuck with a separate project for each?

Solution 1:

I'm generating 2 different APK's (demo and production) from one single source tree with 3 small modifications:

1) I have public static final DEMO=true; //false; in my Application class and depending on that value I used to switch code between demo/production features

2) There are 2 main activities, like:

package mypackage;
public class MyProduction extends Activity 
{
    //blah-blah
}

package mypackage.demo;
public class MyDemoActivity extends mypackage.MyProductionActivity
{
    //blah-blah
}

3) And in the end 2 separate AndroidManifest.xml files which points to different launcher activities depending on demo/production switch

I'm switching between 2 APK's manually, but see nothing difficult in writing small ANT task to switch between them automatically

Solution 2:

One way to do it would be to maintain two separate AndroidManifest.xml, one for each configuration. You can switch back and forth between the two either manually (copying) or automatically (build script).

[edit] This person here has a system to do this kind of thing: http://blog.elsdoerfer.name/2010/04/29/android-build-multiple-versions-of-a-project/

Solution 3:

The answer to this screams Gradle, as explained on this website. It's officially built into Android Studio and is encouraged.

It's amazing; I've built 3 separate apps using the same source code, with customized text and graphics, with no special coding whatsoever. Just some directory and Gradle setup is required, and other posts of mine can be found with answers to both.

It seems to explain all the basics really well. For the answer to your specific question, look for the section Product Flavors under Build Variants, where it describes specifying different flavors.

As the website explains, part of the purpose behind this design was to make it more dynamic and more easily allow multiple APKs to be created with essentially the same code, which sounds exactly like what you're doing.

I probably didn't explain it the best, but that website does a pretty good job.