How to send int array to Java code from C

Question

On Android platform in my native code I have allocated an int array

mBuffer = new int[BUFSIZE];

I want to send this to Java side, Java method is this

public void WriteBuffer(int[] buffer, int size) 
{

}

I call back to java code like this

const char* callback = "WriteBuffer";

mWriteMethod =  env->GetMethodID(cls, callback, "([II)V");

This calls the java method its just that in my Java code the buffer is null. As I am really passing a pointer to memory that was dynamically allocated rather than an actual array is probably why it doesn't work but I don't know how to pass a pointer to Java. I need the buffer parameter as an integer array on the Java side anyway.

Anyone know how I can modify the above to get it to work?

Thanks

You don't need the 'size' parameter in that callback method. The Java code can use buffer.length. — user207421
– user207421, Commented Jun 12, 2012 at 1:14

Community · Accepted Answer · 2015-01-22 14:28:59Z

2

My understanding of your question is you want call the java method WriteBuffer and pass a int[] to it.
Some pseudo-code which you will need in jni

jintArray buffer; 
buffer= (*env)->NewIntArray(env, BUFSIZE); 
(*env)->SetIntArrayRegion(env, buffer, 0,BUFSIZE, mBuffer);

SetIntArrayRegion() will copy from mBuffer into the Java array.

edited Jan 22, 2015 at 14:28

CommunityBot

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answered Jun 11, 2012 at 12:50

bobby

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