第一步，继承std::streambuf
class MyStreamBuf : public std::streambuf{enum{BUFFER_SIZE = 255,};public:MyStreamBuf(){buffer_[BUFFER_SIZE] = '\0';setp(buffer_, buffer_ + BUFFER_SIZE – 1);}~MyStreamBuf(){sync();}protected:virtual int_type overflow(int_type c){if (c != EOF){*pptr() = c;pbump(1);}if (flush_buffer() == EOF){return EOF;}return c;}virtual int sync(){if (flush_buffer() == EOF){return -1;}return 0;}private:int flush_buffer(){int len = int(pptr() – pbase());if (len <= 0)return 0;if (len <= BUFFER_SIZE)buffer_[len] = '\0';#ifdef ANDROIDandroid_LogPriority t = ANDROID_LOG_INFO;__android_log_write(t, "mylog", buffer_);#elseprintf("%s", buffer_);#endifpbump(-len);return len;}private:char buffer_[BUFFER_SIZE + 1];};第二步，，创建MyStreamBuf对象，并指定给std::coutMyStreamBuf g_MyStreamBuf;std::cout.rdbuf(&g_MyStreamBuf);//NOTE: std::endl会立即调用sync方法将缓冲区字符写入log，并不只是换行用std::cout << "hello " << 123 << std::endl;std::cout << "pi = " << 3.14 << std::endl;这样，就可以是Eclipse的LogCat查看std::cout输出了。
没有早一步，也没有晚一步，刚好遇上了你！
