I have some code in C and one of the method has a function pointer as argument. I'm trying to use the C code in my Android app.
I decided to use SWIG to do all the work in generating the java files I need. Everything works well with regular function (the one that doesn't have a function pointer as argument).
But I'm not sure how I can pass my JAVA method as a callback to the C function.
Here is an example :
here is my multiply.h file
typedef int (*callback_t) (int a, int b, int c);
int foo(callback_t callback);
here is my multiply.c file
#include <stdio.h>
#include "multiply.h"
int foo(callback_t callback)
{
return callback(2, 4, 6);
}
here is my interface file multiply-swig.i
%module example
%{
/* Includes the header in the wrapper code */
#include "multiply.h"
%}
/* Parse the header file to generate wrappers */
%include "multiply.h"
then I ran the following swig command to generate the java files I need
swig -java -package com.example.ndktest -o multiply-wrap.c mulitiply-swig.i
and then swig generated the following files :
example.java
package com.example.ndktest;
public class example {
public static int foo(SWIGTYPE_p_f_int_int_int__int callback) {
return exampleJNI.foo(SWIGTYPE_p_f_int_int_int__int.getCPtr(callback));
}
}
exampleJNI.java
package com.example.ndktest;
public class exampleJNI {
public final static native int foo(long jarg1);
}
SWIGTYPE_p_f_int_int_int__int.java
package com.example.ndktest;
public class SWIGTYPE_p_f_int_int_int__int {
private long swigCPtr;
protected SWIGTYPE_p_f_int_int_int__int(long cPtr, boolean futureUse) {
swigCPtr = cPtr;
}
protected SWIGTYPE_p_f_int_int_int__int() {
swigCPtr = 0;
}
protected static long getCPtr(SWIGTYPE_p_f_int_int_int__int obj) {
return (obj == null) ? 0 : obj.swigCPtr;
}
}
Now how can I call this foo method from my java code? The argument is of type SWIGTYPE_p_f_int_int_int__int ??? I don't understand how I can pass a JAVA method as callback to the C code ... I think I am definitely missing something here ....
Any help is appreciated, thanks
