如何避免在Android（或任何Java）项目中包含未使用的库？

Question

My project uses 2 third party libraries (both more than 10 MB in size) for some speech processing features. I need only one of them at a time (almost like a plugin ), a decision I make during build time. I have consumed methods of both libraries in the same module as of now. My build.gradle has flags like these :

buildConfigField "boolean", "USE_LIB_ONE", "true"
buildConfigField "boolean", "USE_LIB_TWO", "false"

In my Java code, I have checks like this :

if (BuildConfig.USE_LIB_ONE) {
    A.method();
} else if(BuildConfig.USE_LIB_TWO) {
    B.method();
}

My questions are:

1. Is there a way to conditionally compile LIBRARY_ONE or LIBRARY_TWO based on buildConfigField? My APK is getting bulky even when I don't use the other library.

2. Is there a cleaner way to design such projects? My codebase is bloated with if/else checks of the same condition.

3. I guess gradle product flavors may help in this case, but I don't know a lot about it. Can someone please confirm if product flavors do help in conditional compilation?

4. Can ServiceLoader be of any help here? On a non-Android project I would be possibly using it, but Android implementation sounds buggy based on some SO posts.

My question is NOT a duplicate of this one .

Answer 1

Currently there is an issue for your question here

but for a workaround you can use flavor + build type configuration in your build.gradle like this

configurations {
  libOneReleaseCompile
  libTwoReleaseCompile
}

dependencies {
    compile 'com.android.support:support-v4:23.1.1'
    compile 'com.android.support:support-annotations:23.1.1'
    compile 'com.android.support:appcompat-v7:23.1.1'

    libOneReleaseCompile 'lib.one.speech'
    libTwoReleaseCompile 'lib.two.speech'
}