Question

Anybody have one example of a android project using a same time C++ and Java together, for example, one normal android project build on eclipse and in there add a cpp class and using this cpp class on java class…

say I have a class Foo on C++

class Foo{
...
}

and I have a class MyActivity on Java

public class MyActivity extends Activity{
...
}

how to i instance the Foo class on MyActivity class?…

thanks a lot for all.

Answer 1

First you have to make a .so of you c++ classes with build_ndk.sh

On the C++ side you have to declare your JNI methods

JNIEXPORT void JNICALL 
Java_org_your_ackage_someFunction(JNIEnv * env, jobject  obj)
{}

On the java side

public class YourActivity extends Activity {
    // Load Native Libary
    static {
        System.loadLibrary("your_lib_name");
    }

    public native void someFunction();
}

Then use the function as you would do in java.

You should take a look at this nice tutorial