cocos2dx通过封装JniHelper类来调用安卓api底层函数，该文件在cocos/platform/android/jni/JniHelper.h，使用方法如下：
打开eclipse，导入cocos2dx的项目为安卓项目，如下所示：
新建一个java文件在org.cocos2dx.lib包下，起名为
Cocos2dxTestJni.java,里面添加一个单例的静态方法和一个成员函数（判断是否开启wifi），如下所示：
package org.cocos2dx.lib;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
public class Cocos2dxTestJni {
private static Cocos2dxTestJni instance = null;
public static Object getInstance()
{
if(instance == null)
instance = new Cocos2dxTestJni();
return instance;
}
public boolean bOpenWifi()
{
Context context = Cocos2dxActivity.getContext();
ConnectivityManager connectivityManager = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo activeNetInfo = connectivityManager.getActiveNetworkInfo();
if(activeNetInfo != null && activeNetInfo.getType() == ConnectivityManager.TYPE_WIFI)
{
System.out.println("wifi is open");
return true;
}
System.out.println("wifi is close");
return false;
}
}
在c＋＋层调用安卓底层函数，首先包含头文件：
#if CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID
#include "platform/android/jni/JniHelper.h"
#include <jni.h>
#endif
调用方法如下：
#if CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID
JniMethodInfo info;
bool ret = JniHelper::getStaticMethodInfo(info,"org/cocos2dx/lib/Cocos2dxTestJni","getInstance","()Ljava/lang/Object;");
jobject jobj;
if(ret)
{
log("success to call getInstance Func");
jobj = info.env->CallStaticObjectMethod(info.classID,info.methodID);
bool ret2 = JniHelper::getMethodInfo(info,"org/cocos2dx/lib/Cocos2dxTestJni","bOpenWifi","()Z");
if(ret2)
{
jboolean jb = info.env->CallBooleanMethod(jobj,info.methodID);
if(jb == JNI_TRUE)
log("success Call bOpenWifi");
else
log("no wifi open");
}
}
else
{
log("failed to call getInstance Func");
}
#endif
JniHelper::getStaticMethodInfo方法是根据脚本文件路径、函数名字、签名缩写来获取方法的具体信息，包括类id，方法id，运行环境等，保存在JniMethodInfo的变量中，
info.env->CallStaticObjectMethod(info.classID,info.methodID);通过类id，方法id调用函数，然后放回一个jobject类型。
具体其他函数可以查看unity圣典的api文档：http://game.ceeger.com/Script/AndroidJNI/AndroidJNI.html
jni的签名缩写的缩写如下表所示：
jni的返回类型如下：
将cocos项目打包成apk包，打开eclipse调试，查看输出
笔者很懒，暂时先写到这里