NDK First Simple Program

Java Code to Call Native Method
step one : Load SystemLib:  
   static {
        System.loadLibrary("manojsamplelibrary");
    }
 
Step Two:    Call below in your onCreate Method

    int size =25;
        int arr[] = new int[size];
        for (int i = 0; i < size; i++) {
            arr[i] = i+10;
           // Log.i("***", ""+arr[i]);
        }
        int sum = getHelloSum(arr,size);

Step Three:  Declare native getHelloSum Method

  public native int  getHelloSum(int[] val,int size); 


Step Four:  Write hello-jni.c

Java_com_manoj_hellojni_HelloJni_getHelloSum(JNIEnv *env, jobject obj,
        jintArray arr,jint size) {
    

    jint buf[size];
    jint i, sum = 0;
    (*env)->GetIntArrayRegion(env, arr, 0, size, buf);
    for (i = 0; i < size; i++) {
        sum += buf[i];
    }


    return sum;
}


Step Five : How to Debug NDK Code

    1.   __android_log_write(ANDROID_LOG_INFO, "TAG", "getHelloSum Method is Called");
                       or
   2.  LOGI("Array Size = (%d) ", size);


  

Comments

  1. http://www.ntu.edu.sg/home/ehchua/programming/android/Android_NDK.html

    ReplyDelete

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