testNDK报错,求帮忙解答解决办法

package com.example.testndk;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        TextView tv=new TextView(this);
        tv.setText(stringFromJNI());
        setContentView(tv);
    }
    
    public native String  stringFromJNI();
    
    static {
        System.loadLibrary("hello-jni");
    }
    
}

#include <string.h>
#include <jni.h>

jstring
Java_com_example_testndk_TestNDK_stringFromJNI( JNIEnv* env,jobject thiz )
{
    return (*env)->NewStringUTF(env, "Hello from JNI !");
}