Cocos2d-x中提供了一个JniHelper类来让我们对Jni进行操作。

Cocos2d-x中提供了一个JniHelper类来让我们对Jni进行操作。

(PS:弄了一天想自己写代码操作Jni的，但是总是出错，技术差不得不使用Cocos2d-x现成的了)。

我们有一个Android工程 ：CocosDemoAndroid

还有一个Win32工程：Cocos2dDemo.win32

这个是必备的。。。

在C++ Win32工程中有一个Scene，点击按钮调用Jni函数。

void CallJni::getInputCallBack(CCObject* pSender){  g_AndroidPlatform.showDialog();}

这个 g_AndroidPlatform.showDialog(); 在这个函数里面 使用JniHelper类来使用Jni 。

void AndroidPlatform::showDialog(){  CCLog("showDialog");#ifdef ANDROID  //下面是利用jnihelper类来调用Android Static  JniMethodInfo methodInfo;  //jni函数信息结构体  /*getStaticMethodInfo获取到MethodId和ClassId,ClassID通过穿进去的Activity即类名获取，MethodId通过函数名获取*/  bool isHave=JniHelper::getStaticMethodInfo(methodInfo,"com/example/cocosdemoandroid/MainActivity","showMessage","()V");  if(isHave)  {    /*调用这个函数*/    methodInfo.env->CallStaticVoidMethod(methodInfo.classID,methodInfo.methodID);  }#endif}

C++层关键的代码就是这两个了，在使用JniHelper的时候不要忘记加上头文件

#ifdef ANDROID#include<jni.h>#include"platform/android/jni/JniHelper.h"#endif

下面来看Android层代码了。

从上面的C++代码中也能看得出来

工程包名 ： com.example.cocosdemoandroid

Activity：MainActivity

public class MainActivity extends Cocos2dxActivity {  public static   Context mContext;      /*****消息类型****/  private static final int SHOW_MESSAGE = 0;    private static Handler handler=new Handler()  {    @Override    public void handleMessage(Message msg)    {      //接受消息然后去做相应的事情      if(msg.what==SHOW_MESSAGE)      {        Log.d("CocosDemoAndroid", String.valueOf(msg.obj));  //获取到Handler传递的参数数据        AlertDialog.Builder builder=new Builder(mContext);        builder.setTitle("C++调用Android");        builder.setMessage("C++调用Android显示弹出框");        builder.show();      }      super.handleMessage(msg);    }  };    @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    mContext=MainActivity.this;  }      @Override  public boolean onCreateOptionsMenu(Menu menu) {    // Inflate the menu; this adds items to the action bar if it is present.    getMenuInflater().inflate(R.menu.main, menu);    return true;  }      public  static void showMessage()  {    Log.d("showMessage", "showMessage");    Message msg=new Message();    msg.what=SHOW_MESSAGE;    msg.obj="showmessage demos";  //可以传递参数    handler.sendMessage(msg);  }    public native int InitJni();    static  {    System.loadLibrary("CocosDemo");  }}

对于Android：

为什么要使用Handle sendMessage() ??

因为如果直接在showMessage中弹出提示框，会崩溃提示 Can't create handle inside thread that has not called Looper.prepare() 

再附上的 Android.mk 文件：

LOCAL_PATH := $(call my-dir)RAKNET_LIB_PATH := ../../../../RakNet_PC-4.08/Android/obj/local/$(TARGET_ARCH_ABI)/libRakNet.a$(call import-add-path, $(Cocos2d)) \$(call import-add-path, $(Cocos2d)\cocos2dx\platform\third_party\android\prebuilt) \include $(CLEAR_VARS)LOCAL_MODULE:=libRakNetLOCAL_SRC_FILES:=$(RAKNET_LIB_PATH)include $(PREBUILT_STATIC_LIBRARY)include $(CLEAR_VARS)LOCAL_MODULE := CocosDemo_sharedLOCAL_CFLAGS:=-w -DANDROID -DRAPIDXML_NO_EXCEPTIONSLOCAL_MODULE_FILENAME := libCocosDemoLOCAL_SRC_FILES := jni.cpp \          ../../Classes/TristanaLayer.cpp  \          ../../Classes/AppDelegate.cpp \          ../../Classes/HelloWorldScene.cpp   \          ../../Classes/CControlTest.cpp   \          ../../Classes/CocosDemoMenu.cpp   \          ../../Classes/CCScrollViewTest.cpp   \          ../../Classes/CocosRakNet.cpp   \          ../../Classes/MissCardSprite.cpp   \          ../../Classes/MoveWithMouse.cpp   \          ../../Classes/TransCards.cpp   \          ../../Classes/AndroidPlatform.cpp   \          ../../../public/network/MissGameNetWork.cpp\          ../../Classes/CallJni.cpp              LOCAL_C_INCLUDES := $(LOCAL_PATH)/../../Classes \$(LOCAL_PATH)/../../../public \$(LOCAL_PATH)/../../../public/network \$(RakNet)/Source \$(Cocos2d)/cocos2dx \$(Cocos2d)/cocos2dx/include \$(Cocos2d)/cocos2dx/kazmath/include \$(Cocos2d)/cocos2dx/platform/android \$(Cocos2d)/cocos2dx/platform/third_party/android \$(Cocos2d)/external \$(Cocos2d)/CocosDenshion/include \$(Cocos2d)/CocosDenshion/android \$(Cocos2d)/extensions \$(Cocos2d)/extensions/GUI/CCControlExtension \LOCAL_STATIC_LIBRARIES:= libRakNetLOCAL_WHOLE_STATIC_LIBRARIES := cocos2dx_static cocosdenshion_static cocos_extension_staticinclude $(BUILD_SHARED_LIBRARY)$(call import-module,CocosDenshion/android) \$(call import-module,cocos2dx) \$(call import-module,extensions)

最后上效果图：

  来自：http://www.tuicool.com/articles/jq2If2