11.Cocos2dx2.2下使用JNI技術調用jar包裡面的一些方法遇到的一些問題及解決方案。

標籤：cocos2dx jni

<span style="font-family: Arial, Helvetica, sans-serif;">步驟一：匯入JniHelper.h標頭檔。</span>

#if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID)#include "JniHelper.h"#endif；

此時會遇到JniHelper.h標頭檔無法找到的問題，需要添加附加元件封裝含目錄即可解決問題。具體操作步驟如下：右擊項目---->c/c++---->常規---->附加元件封裝含目錄---->添加JniHelper.h所在的路徑即可，eg：E:\安卓開發工作空間\cocos2d-x-2.2\cocos2dx\platform\android\jni。
此時可能還會遇到找不到jni.h和jni_md.h的問題，解決方案為在%JAVA_HOME%/include/下找到 jni.h，在%JAVA_HOME%/include/win32/下找到jni_md.h，複製到“Visual Studio目錄/VC/include/”下，即可解決問題。

步驟二：編寫調用java端方法的代碼。

<span style="font-size:18px;">void HelloWorld::fun(){#if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID)JniMethodInfo methodInfo;bool isHave = JniHelper::getStaticMethodInfo(methodInfo,"org/cocos2dx/hellocpp/HelloCpp","showAd","()V");if(isHave){methodInfo.env->CallStaticVoidMethod(methodInfo.classID,methodInfo.methodID);}#endif}</span>

一定要加上平台判斷語句。否則會出現以下bug。（具體如何調用，請參見相關文檔）

<span style="font-size:18px;">錯誤    2    error LNK2019: 無法解析的外部符號 "__declspec(dllimport) public: static bool __cdecl  cocos2d::JniHelper::getStaticMethodInfo(struct cocos2d::JniMethodInfo_ &,char const *,char const *,char const *)" (__imp_? [email protected]@[email protected]@[email protected]@[email protected])，該符號在函數 "public: void __thiscall HelloWorld::fun (void)" ([email protected][email protected]@QAEXXZ) 中被引用    E:\安卓開發工作空間\cocos2d-x-2.2\projects\jni2\proj.win32\HelloWorldScene.obj    HelloCpp</span>

步驟三：將其移植到Android平台，此時會提示在CCPlatformDefine.h檔案中log.h: no such file or directory，即log.h找不到。
解決方案：1.修改Android.mk檔案配置,添加如下語句 LOCAL_LDLIBS += -L$(SYSROOT)/usr/lib -llog2.修改CCPlatformDefine.h檔案注釋掉#include "log.h"，添加#include "ALog.h"。3.建立ALog.h檔案，寫入以下內容，並將其放置於與CCPlatformDefine.h所在的同一目錄下。

<span style="font-size:18px;">#pragma once    #include<android/log.h>    #define LOG_TAG "debug log"  #define LOGI(fmt, args...) __android_log_print(ANDROID_LOG_INFO, LOG_TAG, fmt, ##args)  #define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, fmt, ##args)  #define LOGE(fmt, args...) __android_log_print(ANDROID_LOG_ERROR, LOG_TAG, fmt, ##args) </span>

步驟四：搞完第三步之後，再編譯運行，還會提示如下錯誤。

<span style="font-size:18px;">"E:\\迅雷下載\\android-ndk-r9-windows-x86\\android-ndk-r9\\ndk-build.cmd" Android NDK: WARNING:E:\安卓開發工作空間\cocos2d-x-2.2\/cocos2dx/Android.mk:cocos2dx_static: LOCAL_LDLIBS is always ignored for static libraries    "Compile++ thumb : cocos2dcpp_shared <= HelloWorldScene.cppjni/../../Classes/HelloWorldScene.cpp:3:23: fatal error: JniHelper.h: No such file or directorycompilation terminated.make: *** [obj/local/armeabi/objs/cocos2dcpp_shared/__/__/Classes/HelloWorldScene.o] Error 1</span>

即找不到JniHelper.h這個檔案，解決方案如下。

<span style="font-size:18px;">LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)LOCAL_MODULE := cocos2dcpp_sharedLOCAL_MODULE_FILENAME := libcocos2dcppLOCAL_SRC_FILES := hellocpp/main.cpp                    ../../Classes/AppDelegate.cpp                    ../../Classes/HelloWorldScene.cppLOCAL_C_INCLUDES := $(LOCAL_PATH)/../../Classes                                  E:\安卓開發工作空間\cocos2d-x-2.2\cocos2dx\platform\android\jniLOCAL_WHOLE_STATIC_LIBRARIES += cocos2dx_staticLOCAL_WHOLE_STATIC_LIBRARIES += cocosdenshion_staticLOCAL_WHOLE_STATIC_LIBRARIES += box2d_staticLOCAL_WHOLE_STATIC_LIBRARIES += chipmunk_staticLOCAL_WHOLE_STATIC_LIBRARIES += cocos_extension_staticLOCAL_LDLIBS += -L$(SYSROOT)/usr/lib -lloginclude $(BUILD_SHARED_LIBRARY)$(call import-module,cocos2dx)$(call import-module,cocos2dx/platform/third_party/android/prebuilt/libcurl)$(call import-module,CocosDenshion/android)$(call import-module,extensions)$(call import-module,external/Box2D)$(call import-module,external/chipmunk)</span>

就是在LOCAL_C_INCLUDES := $(LOCAL_PATH)/../../Classes\後面追加JniHelper.h檔案所在的路徑，讓編譯器編譯本地的檔案。相關的Android.mk裡面的一些基礎知識，參見http://www.himigame.com/lua-game/1388.html
步驟五：編寫供c++調用的java方法，如果是第三方jar裡面的方法的話，建議用Handler去觸發，讓其處於在UI線程中運行，否則可能出錯。

<span style="font-size:18px;">package org.cocos2dx.hellocpp;import org.cocos2dx.lib.Cocos2dxActivity;import org.cocos2dx.lib.Cocos2dxGLSurfaceView;import android.content.Context;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.util.Log;import com.manage.LA;public class HelloCpp extends Cocos2dxActivity {/** * 儲存當前Activity執行個體， 靜態變數 */private static Context mActivity = null;protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);mActivity = this;LA.initSDK(mActivity, "1005020");Log.i("HelloCpp","onCreate");}public Cocos2dxGLSurfaceView onCreateView() {Cocos2dxGLSurfaceView glSurfaceView = new Cocos2dxGLSurfaceView(this);// HelloCpp should create stencil bufferglSurfaceView.setEGLConfigChooser(5, 6, 5, 0, 16, 8);return glSurfaceView;}   /** * 顯示廣告 */public static void showAd() {mHandler.sendEmptyMessage(0);Log.i("HelloCpp", "showAd");}public static Handler mHandler = new Handler() {@Overridepublic void handleMessage(Message msg) {// TODO Auto-generated method stubsuper.handleMessage(msg);switch (msg.what) {case 0:LA.showAD1(mActivity);break;}}};static {System.loadLibrary("cocos2dcpp");}}</span>