转自 http://www.cnblogs.com/sevenyuan/p/4202759.html
1. 在Eclipse中创建项目：TestJNI
2. 新创建一个class：TestJNI.java
package com.wwj.jni;
public class TestJNI {
public native boolean Init();
public native int Add(int x, int y);
public native void Destory();
}
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_wwj_jni_TestJNI */
#ifndef _Included_com_wwj_jni_TestJNI
#define _Included_com_wwj_jni_TestJNI
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: com_wwj_jni_TestJNI
* Method: Init
* Signature: ()Z
*/
JNIEXPORT jboolean JNICALL Java_com_wwj_jni_TestJNI_Init
(JNIEnv *, jobject);
/*
* Class: com_wwj_jni_TestJNI
* Method: Add
* Signature: (II)I
*/
JNIEXPORT jint JNICALL Java_com_wwj_jni_TestJNI_Add
(JNIEnv *, jobject, jint, jint);
/*
* Class: com_wwj_jni_TestJNI
* Method: Destory
* Signature: ()V
*/
JNIEXPORT void JNICALL Java_com_wwj_jni_TestJNI_Destory
(JNIEnv *, jobject);
#ifdef __cplusplus
}
#endif
#endif
#ifndef _TEST_JNI_ADD_H_
#define _TEST_JNI_ADD_H_
class CAdd {
public:
CAdd();
~CAdd();
int Add(int x, int y);
};
#endif
Add.cpp
#include "Add.h"
CAdd::CAdd() {
}
CAdd::~CAdd() {
}
int CAdd::Add(int x, int y) {
return x + y;
}
com_wwj_jni_TestJNI.cpp的实现：
#include <stdio.h>
#include <stdlib.h>
#include "com_wwj_jni_TestJNI.h"
#include "Add.h"
CAdd *pCAdd = NULL;
JNIEXPORT jboolean JNICALL Java_com_wwj_jni_TestJNI_Init(JNIEnv *env,
jobject obj) {
if (pCAdd == NULL) {
pCAdd = new CAdd;
}
return pCAdd != NULL;
}
JNIEXPORT jint JNICALL Java_com_wwj_jni_TestJNI_Add(JNIEnv *env, jobject obj,
jint x, jint y) {
int res = -1;
if (pCAdd != NULL) {
res = pCAdd->Add(x, y);
}
return res;
}
JNIEXPORT void JNICALL Java_com_wwj_jni_TestJNI_Destory(JNIEnv *env, jobject obj)
{
if (pCAdd != NULL)
{
pCAdd = NULL;
}
}
LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := TestJNI LOCAL_SRC_FILES := com_wwj_jni_TestJNI.cpp LOCAL_SRC_FILES += Add.cpp include $(BUILD_SHARED_LIBRARY)
APP_PROJECT_PATH := $(call my-dir) APP_MODULES := TestJNI
package com.wwj.jni;
import android.os.Bundle;
import android.widget.TextView;
import android.app.Activity;
public class TestJNIActivity extends Activity {
private TextView textView;
static {
// 加载动态库
System.loadLibrary("TestJNI");
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.textview);
TestJNI testJNI = new TestJNI();
// 调用native方法
boolean init = testJNI.Init();
if (init == true) {
// 调用Add函数
int sum = testJNI.Add(100, 150);
textView.setText("你真是个" + sum);
} else {
textView.setText("你比二百五还要二百五");
}
testJNI.Destory();
}
}
运行项目，效果图如下：
原文：http://www.cnblogs.com/xiaonanxia/p/4809486.html