I am trying to build android application using native code so i want to test if ndk runs successfully.When i try to run my first hello world project log cat says,
01-21 23:30:06.780: E/AndroidRuntime(939): FATAL EXCEPTION: main
01-21 23:30:06.780: E/AndroidRuntime(939): java.lang.UnsatisfiedLinkError:
Native method not found: com.example.ndktesting.MainActivity.invokeNativeFunction:()Ljava/lang/String;
I checked some stackoverflow answers but could not find my answer.Here is my code for java and c.I am using android ndk r8d version.
//ndktest.c
#include <string.h>
#include <jni.h>
extern "C"{
JNIEXPORT jstring JNICALL Java_com_example_ndktesting_ndktest_MainActivity_invokeNativeFunction(JNIEnv* env, jobject thiz)
};
JNIEXPORT jstring JNICALL Java_com_example_ndktesting_ndktest_MainActivity_invokeNativeFunction(JNIEnv* env, jobject thiz){
return (*env)->NewStringUTF(env, "Hello from native code!");
}
Here is my MainActivity java code:
package com.example.ndktesting;
public class MainActivity extends Activity {
//declare the native code function - must match ndktest.c
private native String invokeNativeFunction();
public native String unimplementedinvokeNativeFunction();
// load the library - name matches jni/Android.mk
static {
System.loadLibrary("ndktest");
}
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// this is where we call the native code
String hello = invokeNativeFunction();
new AlertDialog.Builder(this).setMessage(hello).show();
}
}
Android make file code:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
# Here we give our module name and source file(s)
LOCAL_MODULE := ndktest
LOCAL_SRC_FILES := ndktest.c
include $(BUILD_SHARED_LIBRARY)
Your package/class names do not match.
JNIEXPORT jstring JNICALL Java_com_example_ndktesting_ndktest_MainActivity_invokeNativeFunction(JNIEnv* env, jobject thiz)
Would be a method in the class
com.example.ndktesting.ndktest.MainActivity
However your actual code
package com.example.ndktesting;
public class MainActivity extends Activity
causes it to look for
com.example.ndktesting.MainActivity.invokeNativeFunction
without the "ndktest"
Once you make the names match it should either work, or expose the next issue.
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