今天我们要学习的就是cocos2d-x 多线程编程，对这方面还有不了解或者感兴趣的同学可以看一下。

就像每个进程有一个进程ID一样，每个线程也有一个线程ID，进程ID在整个系统中是唯一的，但线程不同，线程ID只在它所属的进程环境中有效。线程ID用pthread_t数据类型来表示，实现的时候可以用一个结构来代表pthread_t数据类型，所以可以移植的操作系统不能把它作为整数处理。因此必须使用函数来对来对两个线程ID进行比较。

返回值：若相等返回非0值，否则返回0

返回值：调用线程的线程id

线程的创建

1. DownLoader.h
2. //
3. //  DownLoader.h
4. //  MythLeague
5. //
6. //
7. //
8. /*
9. * 1.开线程
10. * 2.下载分配给自己的资源
11. * 3.监听自己是否下载完
12. * 4.和管理器交互
13. */
14. #ifndef __MythLeague__DownLoader__
15. #define __MythLeague__DownLoader__
16. #include "Global/Constants.h"
17. typedef enum{
18. DownloadStatus_Init,
19. DownloadStatus_Loading,
20. DownloadStatus_Success,
21. DownloadStatus_FailedWhen_Init,
22. DownloadStatus_FailedWhen_GetHandle,
23. DownloadStatus_FailedWhen_GetInfo,
24. }Enum_DownloadStatus;
25. // 下载任务
26. typedef struct {
27. std :: string resUrl;
28. std :: string fileName;
29. }Struct_DownLoadTask;
30. class DownLoader : public cocos2d::CCObject{ public: DownLoader();
31.  virtual ~DownLoader();
32.  CREATE_FUNC(DownLoader); 
33. bool init(); //下载资源
34.  void downloadRes(Struct_DownLoadTask p_downloadTask); //开线程 
35. static void* startNewThread(void* args);
36.  bool startDownload(); //处理下载数据 
37. static size_t process_data(void *buffer, size_t size, size_t nmemb, std::string& user_p); //监测下载完毕
38. void checkDownloadStatus(float p_delay); 
39. public: Struct_DownLoadTask m_downloadTask; Enum_DownloadStatus m_iDownloadStatus; };
40.  #endif /* defined(__MythLeague__DownLoader__) */
41. #include "DownLoader.h"
42. #include "DownloadMgr.h"
43. #include "Global/Tools.h"
44. #define FILE_EXIST (200)
45. #if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
46. #include "CURL/curl.h"
47. #elif (CC_TARGET_PLATFORM == CC_PLATFORM_WIN32)
48. #include "platform/third_party/win32/curl/curl.h"
49. #elif (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID)
50. #include "platform/third_party/android/modules/libcurl/include/curl/curl.h"
51. #endif
52. using namespace std;
53. using namespace cocos2d;
54. #define DownLoader_Check_Interval (0.5f)
55. DownLoader::DownLoader(){
56. m_iDownloadStatus = DownloadStatus_Init;
57. }
58. DownLoader::~DownLoader(){
59. }
60. bool DownLoader::init(){
61. return true;
62. }
63. //下载资源
64. void DownLoader::downloadRes(Struct_DownLoadTask p_downloadTask){
65. m_downloadTask = p_downloadTask;
66. pthread_t l_pid;
67. pthread_attr_t l_attr;
68. pthread_attr_init(&l_attr);
69. int l_iPriority = sched_get_priority_max(SCHED_OTHER);
70. pthread_attr_setschedpolicy(&l_attr, l_iPriority);
71. pthread_create(&l_pid, &l_attr, DownLoader::startNewThread, this);
72. CCDirector::sharedDirector()->getScheduler()->scheduleSelector(schedule_selector(DownLoader::checkDownloadStatus), this, DownLoader_Check_Interval, false);
73. }
74. //开线程(静态方法)
75. void* DownLoader::startNewThread(void* p_args){
76. //线程独立
77. pthread_detach(pthread_self());
78. //自己新线程里下载
79. DownLoader* l_thisDownloader = (DownLoader*)p_args;
80. l_thisDownloader->startDownload();
81. return NULL;
82. }
83. bool DownLoader::startDownload(){
84. m_iDownloadStatus = DownloadStatus_Loading;
85. #if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS || CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID)
86. // 初始化libcurl
87. CURLcode return_code;
88. return_code = curl_global_init(CURL_GLOBAL_ALL);
89. if (CURLE_OK != return_code)
90. {
91. CCLog("init libcurl failed.");
92. curl_global_cleanup();
93. m_iDownloadStatus = DownloadStatus_FailedWhen_Init;
94. return false;
95. }
96. // 获取easy handle
97. CURL *easy_handle = curl_easy_init();
98. if (NULL == easy_handle)
99. {
100. CCLog("get a easy handle failed.");
101. curl_easy_cleanup(easy_handle);
102. curl_global_cleanup();
103. m_iDownloadStatus = DownloadStatus_FailedWhen_GetHandle;
104. return false;
105. }
106. // 设置easy handle属性
107. return_code = curl_easy_setopt(easy_handle, CURLOPT_URL, m_downloadTask.resUrl.c_str());
108. //设置回调函数
109. //return_code = curl_easy_setopt(easy_handle, CURLOPT_WRITEFUNCTION, &process_data);
110. curl_easy_setopt(easy_handle, CURLOPT_WRITEFUNCTION, process_data);
111. //回调函数的额外参数
112. std::string connectx;
113. return_code = curl_easy_setopt(easy_handle, CURLOPT_WRITEDATA, &connectx);
114. // 执行数据请求
115. return_code = curl_easy_perform(easy_handle);
116. //判断获取响应的http地址是否存在,若存在则返回200,400以上则为不存在,一般不存在为404错误
117. int retcode = 0;
118. return_code = curl_easy_getinfo(easy_handle, CURLINFO_RESPONSE_CODE , &retcode);
119. if (CURLE_OK == return_code && FILE_EXIST == retcode)
120. {
121. double length = 0;
122. return_code = curl_easy_getinfo(easy_handle, CURLINFO_CONTENT_LENGTH_DOWNLOAD , &length);
123. string l_fullPath = Tools::getWritableFilePath(m_downloadTask.fileName.c_str());
124. FILE *fp = fopen(l_fullPath.c_str(), "wb+");
125. if(fp != NULL){
126. fwrite(connectx.c_str(), 1, length, fp);//返回实际写入文本的长度,若不等于length则写文件发生错误.
127. fclose(fp);
128. }else{
129. CCLog("error here file: %s line: %d", __FILE__, __LINE__);
130. }
131. }
132. else
133. {
134. CCLog("......url文件不存在!");
135. curl_easy_cleanup(easy_handle);
136. curl_global_cleanup();
137. m_iDownloadStatus = DownloadStatus_FailedWhen_GetInfo;
138. return false;
139. }
140. // 释放资源
141. curl_easy_cleanup(easy_handle);
142. curl_global_cleanup();
143. #endif
144. m_iDownloadStatus = DownloadStatus_Success;
145. return 0;
146. }
147. //处理下载数据
148. size_t DownLoader::process_data(void *buffer, size_t size, size_t nmemb, std::string& user_p){
149. user_p.append((char*)buffer, size*nmemb);
150. return size*nmemb;
151. }
152. //监测下载完毕
153. void DownLoader::checkDownloadStatus(float p_delay){
154. if (m_iDownloadStatus >= DownloadStatus_Success) {
155. CCDirector::sharedDirector()->getScheduler()->unscheduleSelector(schedule_selector(DownLoader::checkDownloadStatus), this);
156. //成功回调
157. if (m_iDownloadStatus == DownloadStatus_Success) {
158. DownloadMgr::sharedMgr()->callWhenDownloaderFinish_success(this);
159. }
160. //失败回调
161. else{
162. DownloadMgr::sharedMgr()->callWhenDownloaderFinish_failed(this);
163. }
164. }
165. }

/*
* 1. 管理下载器 , 一个或多个
* 2. 显示 DownLoading 及进度
*   并屏蔽事件
* 3. 与外部交互的接口
*/