The Android Native Development Kit (NDK) - Beginning Android 3D Game Development - page 396

Naming Native Functions
The native function declared in the Java code must match the function name declared in the native
C/C++ code based on certain formatting, as follows:

1. The function starts with “Java.”

It is followed by the package name “ robs_gldemo_robsgl20tutorial ” from
the example in Listing 11-1.

2.

This is followed by the class name “ GLES20TriangleRenderer ” from the
example in Listing 11-1.

3.

Next comes the function name “ RobsstringFromJNI ” from the example in
Listing 11-1.

4.

See the full function name in Listing 11-2.

Listing 11-2. The Native RobsstringFromJNI() Function

jstring
Java_robs_gldemo_robsgl20tutorial_GLES20TriangleRenderer_RobsstringFromJNI (JNIEnv* env, jobject thiz
)
{
return (*env)->NewStringUTF(env, "Rob's String Text Message!");
}

Native Function Parameters
The parameter list for a native function always starts with a pointer to JNIEnv, which is the Java
Interface Pointer, for example, env in our native function from Listing 11-2.

JNIEnv* env

The second parameter is a reference to the object, if the native function is nonstatic, for example,
thiz in our native function example from Listing 11-2.

jobject thiz

However, if the native function is static, the second parameter is a reference to its Java class.