【Cocos2d-x】可以显示在线图片的CCSprite

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可以显示在线图片的CCSprite，使用HttpClient异步请求图片数据，当请求成功时，保存图片数据到本地，然后更新CCSprite的纹理，下载中时显示默认图片（可以设置默认图片）。

OnlineImageSprite.h

#ifndef __ONLINEIMAGESPRITE_H__#define __ONLINEIMAGESPRITE_H__#include "cocos2d.h"USING_NS_CC;#include "cocos-ext.h"USING_NS_CC_EXT;// 可以显示在线图片的CCSpriteclass OnlineImageSprite:public CCSprite{public:/*创建一个显示在线图片的Sprite* defaultImagePath默认图片路径（当图片加载中时显示）* url图片url*/static OnlineImageSprite* create(const char* defaultImagePath, const char* url);bool init(const char* defaultImagePath, const char* url);void onDownloadCompleted(CCHttpClient *sender, CCHttpResponse *response);protected:// 下载图片void downloadImage(const char* url);// 获取图片路径std::string getImagePath(const char* url);// 图片是否存在bool isExist(const char* url);// 保存图片std::string saveImage(const std::string& data);private:const char* m_url;};#endif

OnlineImageSprite.cpp

#include "OnlineImageSprite.h"#include <string>using namespace std;   string&   replace_all(string&   str,const   string&   old_value,const   string&   new_value)   {   while(true)   {   string::size_type   pos(0);   if(   (pos=str.find(old_value))!=string::npos   )   str.replace(pos,old_value.length(),new_value);   else   break;   }   return   str;   }   string&   replace_all_distinct(string&   str,const   string&   old_value,const   string&   new_value)   {   for(string::size_type   pos(0);   pos!=string::npos;   pos+=new_value.length())   {   if(   (pos=str.find(old_value,pos))!=string::npos   )   str.replace(pos,old_value.length(),new_value);   else   break;   }   return   str;   }   OnlineImageSprite* OnlineImageSprite::create(const char* defaultImagePath, const char* url){OnlineImageSprite* pSprite = new OnlineImageSprite();if (pSprite && pSprite->init(defaultImagePath,url)){pSprite->autorelease();return pSprite;}CC_SAFE_DELETE(pSprite);return NULL;}bool OnlineImageSprite::init(const char* defaultImagePath, const char* url){m_url = url;CCTexture2D* pTexture = NULL;// 图片是否存在，如果不存在使用默认纹理并下载图片if (isExist(url)){const char* path = getImagePath(url).c_str();pTexture = CCTextureCache::sharedTextureCache()->addImage(path);}else{pTexture = CCTextureCache::sharedTextureCache()->addImage(defaultImagePath);// 下载图片downloadImage(url);}// 初始化if (CCSprite::initWithTexture(pTexture)){return true;}return false;}//判断图片是否已经存在bool OnlineImageSprite::isExist(const char* url){std::string path = getImagePath(url);return CCFileUtils::sharedFileUtils()->isFileExist(path);}//获取图片全路径std::string OnlineImageSprite::getImagePath(const char* url){std::string urlStr = url;replace_all(urlStr,"/","");replace_all(urlStr,"\\","");replace_all(urlStr,":","");replace_all(urlStr,".","");return CCFileUtils::sharedFileUtils()->getWritablePath().append("/").append(urlStr);}// 下载图片void OnlineImageSprite::downloadImage(const char* url){// 发起http请求，下载图片CCHttpRequest* request = new CCHttpRequest();request->setUrl(url);request->setRequestType(CCHttpRequest::kHttpGet);request->setResponseCallback(this, httpresponse_selector(OnlineImageSprite::onDownloadCompleted));CCHttpClient::getInstance()->send(request);request->release();}// 请求回调void OnlineImageSprite::onDownloadCompleted(CCHttpClient *sender, CCHttpResponse *response){if (!response){return;}// 返回码int statusCode = response->getResponseCode();char statusString[64] = {};sprintf(statusString, "HTTP Status Code: %d", statusCode);CCLog("response code: %d", statusCode);// 请求失败if (!response->isSucceed()) {CCLog("response failed");CCLog("error buffer: %s", response->getErrorBuffer());return;}// dump datastd::vector<char> *buffer = response->getResponseData();std::string data (buffer->begin(),buffer->end());std::string path =saveImage(data);//如果保存图片成功，更新纹理if (path != ""){CCTexture2D* pTexture = CCTextureCache::sharedTextureCache()->addImage(path.c_str());if (pTexture){setTexture(pTexture);}}}// 保存图片std::string OnlineImageSprite::saveImage(const std::string& data){std::string path = this->getImagePath(m_url);FILE* file = fopen(path.c_str(), "wb");if (file){// 1.buff// 2.每次写的字节数// 3.写多少次结束// 4.文件句柄fwrite(data.c_str(), 1,data.length(), file);fclose(file);return path;}return "";}

使用示例：

//创建OnlineImageSpirte，参数：1.默认图片路径 2.在线图片的urlCCSprite* pSprite = OnlineImageSprite::create("HelloWorld.png","http://cc.cocimg.com/cocos2dx/image/logo.png");//设置位置pSprite->setPosition(ccp(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y));//添加到Layerthis->addChild(pSprite, 0);

项目地址：https://coding.net/u/linchaolong/p/OnlineImageSprite/git

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