Using existing shared library (.so) in Android application

Question

I have the follow scenario to work on. I was given a shared library (libeffect.so) to use in a Android project i am working for a client. I dont have the shared library source code, i have just the .so file with me. The library is pre-compiled to work on android devices. Along with the shared library I have the method signature

public static native void doEffect(int param1, IntBuffer intBuffer);

So now I have some questiosn on how to make the call to this native method, of source, if this is possible having just the .so file, so there they are:

1. Do I need to place the native method signature in the same package/class as those defined when the .so was or I can use this signature in any package/class in my project that during runtime the jvm will be able to find the method in the shared library? For example, if this shared library was firstly used in a class mypackage.MyClass, do I need to create the same package, class and then put the method signature there?

2. Where do I need to place this .so file inside my eclipse android project to get this file deployed inside my apk file?

These question might sound noob, but I have never worked with jndi before so I am a bit concerned if calling the method doEffect without any error can be achieve. Any answer that can guide me is very welcome.

Many Thanks Thiago

Answer 1

1. Do I need to place the native method signature in the same package/class as those defined when the .so was or I can use this signature in any package/class in my project that during runtime the jvm will be able to find the method in the shared library? For example, if this shared library was firstly used in a class mypackage.MyClass, do I need to create the same package, class and then put the method signature there?

No need to create same package/class. You can put the method signature in any package.

public class NativeLib {

  static {
    System.loadLibrary("so_file");
  }

  public static native void doEffect(int param1, IntBuffer intBuffer);

}

2.Where do I need to place this .so file inside my eclipse android project to get this file deployed inside my apk file?

You have put this .so file in lib folder of your application . IF lib folder is not there then you can create a lib folder and put the .so file. you can call it by using System.loadLibrary("so_ file");