MainActivity.java

package com.xiaofei.app.ndk; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.EditText; import android.widget.TextView; public class MainActivity extends Activity {
       private EditText editText_num1,editText_num2;     private TextView textView_result;     //加载动态链接库     static     {
           System.loadLibrary("hello");     }     @Override     protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         editText_num1= (EditText) findViewById(R.id.editText);         editText_num2= (EditText) findViewById(R.id.editText1);         textView_result= (TextView) findViewById(R.id.textView);     }     //声明一个本地方法，该方法由C。c++实现    public  native  int add(int num1, int num2);     public void addClick(View view)     {
        String num1=editText_num1.getText().toString();         String num2=editText_num2.getText().toString();         //调用本地方法        int result= add(Integer.parseInt(num1),Integer.parseInt(num2));     textView_result.setText(textView_result.toString()+result);     } }

activity_main.xml

Android.mk

LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE:= hello LOCAL_SRC_FILES := hello.c include $(BUILD_SHARED_LIBRARY)

com_xiaofei_app_ndk_MainActivity.h

/* DO NOT EDIT THIS FILE - it is machine generated */ #include 
    
      /* Header for class com_xiaofei_app_ndk_MainActivity */ #ifndef _Included_com_xiaofei_app_ndk_MainActivity #define _Included_com_xiaofei_app_ndk_MainActivity #ifdef __cplusplus extern "C" {
   #endif /*  * Class:     com_xiaofei_app_ndk_MainActivity  * Method:    add  * Signature: (II)I  */ JNIEXPORT jint JNICALL Java_com_xiaofei_app_ndk_MainActivity_add   (JNIEnv *, jobject, jint, jint); #ifdef __cplusplus } #endif #endif
    

hello.c

#include "com_xiaofei_app_ndk_MainActivity.h" JNIEXPORT jint JNICALL Java_com_xiaofei_app_ndk_MainActivity_add   (JNIEnv * env, jobject obj, jint num1, jint num2)   {
           return num1+num2;   }