cocos2d-x游戏引擎核心之十——网络通信
一、建立基本的http通信并得到返回信息
1、创建cocos2dx工程
2、项目引用外部库
如果要使用cocos2dx的CCHttpClient来进行网络访问，则需要引入cocos2dx的相关库，详细步骤如下:
右键单击项目->属性->c/c++->常规，在右边的附件包含目录中添加cocos2dx的extensions目录对应的路径。
然后,右键单击项目->属性->链接器->输入，在右边的附件依赖项中添加libcurl_imp.lib和libExtensions.lib两个库，用分号隔开。
如果不引入extensions文件夹，会出现找不到CCHttpClient的错误；如果不引入libcurl_imp.lib和libExtensions.lib两个库，编译项目时也会出现报错。另外注意引入头文件:
#include "cocos-ext.h"
3.添加下载按钮和回调函数
CCMenuItemImage *pDownloadItem = CCMenuItemImage::create( "bt_blue_light.png", "bt_blue_light.png", this, menu_selector(HelloWorld::menuDownloadCallback) ); CC_BREAK_IF(!pDownloadItem); CCSize pWinSize = CCDirector::sharedDirector()->getWinSize(); CCMenu* pDownloadMenu = CCMenu::create(pDownloadItem, NULL); pDownloadMenu->setPosition(ccp(50 ,50)); CC_BREAK_IF(! pDownloadMenu); this->addChild(pDownloadMenu, 1);
添加按钮的回调函数:
void HelloWorld::menuDownloadCallback(CCObject* pSender) { cocos2d::extension::CCHttpRequest* request = new cocos2d::extension::CCHttpRequest(); request->setUrl("http://www.oschina.net/action/api/news_list"); request->setRequestType(cocos2d::extension::CCHttpRequest::kHttpPost); std::vector<std::string> headers; headers.push_back("Content-Type: application/json; charset=utf-8"); request->setHeaders(headers); const char* postData = "catalog=2&pageIndex=1&pageSize=5"; request->setRequestData(postData ,strlen(postData)); request->setResponseCallback(this, callfuncND_selector(HelloWorld::onHttpRequestCompleted)); request->setTag("Post_My_Data"); cocos2d::extension::CCHttpClient::getInstance()->send(request); request->release(); }
按钮的回调函数里向服务器发起http请求了，request->setResponseCallback(this, callfuncND_selector(HelloWorld::onHttpRequestCompleted))一行代码，向请求结束时添加了onHttpRequestCompleted回调函数：
4.为http request 结束增加回调函数并读取网络数据
void HelloWorld::onHttpRequestCompleted(cocos2d::CCNode *sender ,void *data) { AllocConsole(); freopen("CONIN$", "r", stdin); freopen("CONOUT$", "w", stdout); freopen("CONOUT$", "w", stderr); cocos2d::extension::CCHttpResponse *response = (cocos2d::extension::CCHttpResponse*)data; if (!response) { return; } if (0 != strlen(response->getHttpRequest()->getTag())) { CCLog("%s completed", response->getHttpRequest()->getTag()); } int statusCode = response->getResponseCode(); char statusString[64] = {}; sprintf(statusString ,"Http status code:%d ,tag = %s" ,statusCode ,response->getHttpRequest()->getTag()); CCLog("response code:%d" ,statusCode); if (!response->isSucceed()) { CCLog("response failed"); CCLog("error buffer:%s" ,response->getErrorBuffer()); } std::vector<char> *buffer = response->getResponseData(); printf("Http response,dump data:"); std::string result = ""; for (unsigned int i = 0; i < buffer->size(); i ++) { printf("%c" ,(*buffer)[i]); } }
debug时就能看到reponse中服务器返回的数据了
注：上面操作遇到的问题
（1） 1>libExtensions.lib(HttpClient.obj) : error LNK2019: 无法解析的外部符号 __imp__pthread_create，该符号在函数 "private: bool __thiscall cocos2d::extension::CCHttpClient::lazyInitThreadSemphore(void)" (?lazyInitThreadSemphore@CCHttpClient@extension@cocos2d@@AAE_NXZ) 中被引用。
解决方法：刚开始这里我是不理解的,因为我以为lib库只需要添加一个libExtensions.lib就行...其实还需要其他俩个lib库文件,pthreadVCE2.lib，libcurl_imp.lib，添加方法(Vs2012):项目属性->链接器->输入->附加依赖项。
（2）error LNK2038: 检测到“_ITERATOR_DEBUG_LEVEL”的不匹配项: 值“0”不匹配值“2”
error:
vtkCommon.lib(vtkSmartPointerBase.obj) : error LNK2038: 检测到“_ITERATOR_DEBUG_LEVEL”的不匹配项:值“0”不匹配值“2”(cloudviewer.obj 中)
1>vtkCommon.lib(vtkGarbageCollector.obj) : error LNK2038: 检测到“_ITERATOR_DEBUG_LEVEL”的不匹配项: 值“0”不匹配值“2”(cloudviewer.obj 中)
1>vtkCommon.lib(vtkDebugLeaksManager.obj) : error LNK2038: 检测到“_ITERATOR_DEBUG_LEVEL”的不匹配项: 值“0”不匹配值“2”(cloudviewer.obj 中)
错误原因是：Debug使用了Release的库文件。
即使你连接库里面两个都添加着呢，但是release库文件放在了debug前面，也是出错的。默认按顺序使用库文件。
类似错误：如release下使用了Debug的库文件，报错类似：
error LNK2038: 检测到“_ITERATOR_DEBUG_LEVEL”的不匹配项: 值“2”不匹配值“0”.
解决方法：把Debug模式改为Release模式，编译生成之后，在项目文件夹中运行.exe文件(这里还报了找不到图片资源的错误，把图片资源拷贝到.exe文件同等目录下则可)
#ifndef __HELLOWORLD_SCENE_H__ #define __HELLOWORLD_SCENE_H__ #include "cocos2d.h" #include "SimpleAudioEngine.h" #include "cocos-ext.h" class HelloWorld : public cocos2d::CCLayer { public: // Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone virtual bool init(); // there's no 'id' in cpp, so we recommand to return the exactly class pointer static cocos2d::CCScene* scene(); // a selector callback void menuCloseCallback(CCObject* pSender); void onHttpRequestCompleted(cocos2d::CCNode *sender ,void *data); // implement the "static node()" method manually CREATE_FUNC(HelloWorld); }; #endif // __HELLOWORLD_SCENE_H__
#include "HelloWorldScene.h" using namespace cocos2d; CCScene* HelloWorld::scene() { CCScene * scene = NULL; do { // 'scene' is an autorelease object scene = CCScene::create(); CC_BREAK_IF(! scene); // 'layer' is an autorelease object HelloWorld *layer = HelloWorld::create(); CC_BREAK_IF(! layer); // add layer as a child to scene scene->addChild(layer); } while (0); // return the scene return scene; } // on "init" you need to initialize your instance bool HelloWorld::init() { bool bRet = false; do { ////////////////////////////////////////////////////////////////////////// // super init first ////////////////////////////////////////////////////////////////////////// CC_BREAK_IF(! CCLayer::init()); ////////////////////////////////////////////////////////////////////////// // add your codes below... ////////////////////////////////////////////////////////////////////////// // 1. Add a menu item with "X" image, which is clicked to quit the program. // Create a "close" menu item with close icon, it's an auto release object. CCMenuItemImage *pCloseItem = CCMenuItemImage::create( "CloseNormal.png", "CloseSelected.png", this, menu_selector(HelloWorld::menuCloseCallback)); CC_BREAK_IF(! pCloseItem); // Place the menu item bottom-right conner. pCloseItem->setPosition(ccp(CCDirector::sharedDirector()->getWinSize().width - 20, 20)); // Create a menu with the "close" menu item, it's an auto release object. CCMenu* pMenu = CCMenu::create(pCloseItem, NULL); pMenu->setPosition(CCPointZero); CC_BREAK_IF(! pMenu); // Add the menu to HelloWorld layer as a child layer. this->addChild(pMenu, 1); // 2. Add a label shows "Hello World". // Create a label and initialize with string "Hello World". CCLabelTTF* pLabel = CCLabelTTF::create("Hello World", "Arial", 24); CC_BREAK_IF(! pLabel); // Get window size and place the label upper. CCSize size = CCDirector::sharedDirector()->getWinSize(); pLabel->setPosition(ccp(size.width / 2, size.height - 50)); // Add the label to HelloWorld layer as a child layer. this->addChild(pLabel, 1); // 3. Add add a splash screen, show the cocos2d splash image. CCSprite* pSprite = CCSprite::create("HelloWorld.png"); CC_BREAK_IF(! pSprite); // Place the sprite on the center of the screen pSprite->setPosition(ccp(size.width/2, size.height/2)); // Add the sprite to HelloWorld layer as a child layer. this->addChild(pSprite, 0); bRet = true; } while (0); return bRet; } void HelloWorld::menuCloseCallback(CCObject* pSender) { // "close" menu item clicked //CCDirector::sharedDirector()->end(); cocos2d::extension::CCHttpRequest* request = new cocos2d::extension::CCHttpRequest(); request->setUrl("http://www.oschina.net/action/api/news_list"); request->setRequestType(cocos2d::extension::CCHttpRequest::kHttpPost); std::vector<std::string> headers; headers.push_back("Content-Type: application/json; charset=utf-8"); request->setHeaders(headers); const char* postData = "catalog=2&pageIndex=1&pageSize=5"; request->setRequestData(postData ,strlen(postData)); request->setResponseCallback(this, callfuncND_selector(HelloWorld::onHttpRequestCompleted)); request->setTag("Post_My_Data"); cocos2d::extension::CCHttpClient::getInstance()->send(request); request->release(); } void HelloWorld::onHttpRequestCompleted(cocos2d::CCNode *sender ,void *data) { AllocConsole(); freopen("CONIN$", "r", stdin); freopen("CONOUT$", "w", stdout); freopen("CONOUT$", "w", stderr); cocos2d::extension::CCHttpResponse *response = (cocos2d::extension::CCHttpResponse*)data; if (!response) { return; } if (0 != strlen(response->getHttpRequest()->getTag())) { CCLog("%s completed", response->getHttpRequest()->getTag()); } int statusCode = response->getResponseCode(); char statusString[64] = {}; sprintf(statusString ,"Http status code:%d ,tag = %s" ,statusCode ,response->getHttpRequest()->getTag()); CCLog("response code:%d" ,statusCode); if (!response->isSucceed()) { CCLog("response failed"); CCLog("error buffer:%s" ,response->getErrorBuffer()); } std::vector<char> *buffer = response->getResponseData(); printf("Http response,dump data:"); std::string result = ""; for (unsigned int i = 0; i < buffer->size(); i ++) { printf("%c" ,(*buffer)[i]); } }
二、使用libjson来解析网络json数据
