初学jni，android调用so，运行出错

按照网上教程编得程序，运行时android程序直接异常退出：

附源码，java和cpp

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    TextView JNITest = (TextView)findViewById(R.id.jniTextView);
    String str = getJNItest();
    JNITest.setText(str);

}


static{
    System.loadLibrary("JNITest");
}
public native String getJNItest();

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

extern "C"
_jstring* Java_com_john_helloJNI_getJNItest(JNIEnv* env, jobject thiz){
return (env)->NewStringUTF("hello FROM jni by  ndkTest!");
}

看看能不能解决 http://www.cnblogs.com/javawebsoa/archive/2013/07/30/3225942.html
P.S JNI 用起来太麻烦 试试看JNA？

http://www.cnblogs.com/sevenyuan/p/4202759.html