README.md

Jni android sample

JNI stands for Java Native Interface. This sample is showing how to call native c/c++ method to be used inside android. In order to run this sample, you need to install NDK in android SDK manager beforehand.

If you looked through, the project contains c/c++ file which contains:

#include <jni.h>
#include "sample-jni.h"


extern "C"
JNIEXPORT jint JNICALL

Java_com_pramonow_androidadvanced_JniActivity_getKey(JNIEnv* pEnv, jobject instance, jint key1) {
    return key1+200;
}

And the getKey function will be able to be called inside the activity:

//Our Jni method
external fun getKey(key:Int):Int

companion object {
    init {
        System.loadLibrary("sample-jni")
    }
}

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_jni)

    Toast.makeText(this,getKey(55).toString(),Toast.LENGTH_SHORT).show() // will show 255
}