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'tcreatehandleinsidethreadthathasnotcalledLooper.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)cocos2dxplatformthird_partyandroidprebuilt) 

include $(CLEAR_VARS)

LOCAL_MODULE				:=	libRakNet
LOCAL_SRC_FILES			:=$(RAKNET_LIB_PATH)

include $(PREBUILT_STATIC_LIBRARY)


include $(CLEAR_VARS)

LOCAL_MODULE := CocosDemo_shared

LOCAL_CFLAGS				:=	-w -DANDROID -DRAPIDXML_NO_EXCEPTIONS

LOCAL_MODULE_FILENAME := libCocosDemo

LOCAL_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	:= 	libRakNet
LOCAL_WHOLE_STATIC_LIBRARIES := cocos2dx_static cocosdenshion_static cocos_extension_static

include $(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