ProGuard and the newer R8 are optimizers and obfuscators for Java and Android applications. You can use these tools with your libGDX application to make it harder for 3rd parties to decompile your app, reduce your apps size and even increase the runtime speed by ahead-of-time optimizations like inlining.

    The following configuration file will make your libGDX app work with ProGuard/R8:

    1. # To enable ProGuard in your project, edit project.properties
    2. # to define the proguard.config property as described in that file.
    3. #
    4. # Add project specific ProGuard rules here.
    5. # By default, the flags in this file are appended to flags specified
    6. # in ${sdk.dir}/tools/proguard/proguard-android.txt
    7. # You can edit the include path and order by changing the ProGuard
    8. # include property in project.properties.
    9. #
    10. # For more details, see
    11. #   http://developer.android.com/guide/developing/tools/proguard.html
    13. # Add any project specific keep options here:
    15. # If your project uses WebView with JS, uncomment the following
    16. # and specify the fully qualified class name to the JavaScript interface
    17. # class:
    18. #-keepclassmembers class fqcn.of.javascript.interface.for.webview {
    19. #   public *;
    20. #}
    22. -verbose
    24. -dontwarn com.badlogic.gdx.backends.android.AndroidFragmentApplication
    25. -dontwarn com.badlogic.gdx.utils.GdxBuild
    26. -dontwarn com.badlogic.gdx.physics.box2d.utils.Box2DBuild
    27. -dontwarn com.badlogic.gdx.jnigen.BuildTarget*
    28. -dontwarn com.badlogic.gdx.graphics.g2d.freetype.FreetypeBuild
    30. # Required if using Gdx-Controllers extension
    31. -keep class com.badlogic.gdx.controllers.android.AndroidControllers
    33. # Required if using Box2D extension
    34. -keepclassmembers class com.badlogic.gdx.physics.box2d.World {
    35.    boolean contactFilter(long, long);
    36.    void    beginContact(long);
    37.    void    endContact(long);
    38.    void    preSolve(long, long);
    39.    void    postSolve(long, long);
    40.    boolean reportFixture(long);
    41.    float   reportRayFixture(long, float, float, float, float, float);
    42. }

    Note that you will also have to keep any classes that you access via reflection yourself! Please refer to the ProGuard/R8 documentation for more details.

    To apply ProGuard/R8 to your Android project on Release builds, you need to add the following config to build.gradle file (the one in the android/ folder of your project, not the root build.gradle)

    1. buildTypes {
    2.         release {
    3.             minifyEnabled true
    4.             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    5.         }
    6.     }