这一节很短,但是站在这一节wxWidgest流操作(一)wxFileInputStream与wxFileOutputStream 肩上的。
wxTextInputStream和wxTextOutputStream允许以行为单位来操纵流,特别适合于处理文本文件。
利用这节的界面,打开源码后找到菜单File->&Open 子项的代码:
void StreamAppFrame::OnStreamClick(wxCommandEvent& event) { wxString filename(wxT("streamMain.cpp")); wxString dummyfile(wxT("dummy.cpp")); wxFileInputStream inStream(filename); wxFileOutputStream outStream(dummyfile); int byteCount=inStream.GetLength(); static char buffer[1024*1024*1024]; wxString content; while(byteCount>0) { size_t bytesToRead=wxMin((size_t)sizeof(buffer),byteCount); if(inStream.Read((void*)buffer,bytesToRead).GetLastError()==wxSTREAM_NO_ERROR) { if(outStream.Write((void*)buffer,bytesToRead).GetLastError()==wxSTREAM_NO_ERROR) { content=wxString::FromUTF8(buffer,bytesToRead); byteCount-=bytesToRead; } *text1<<content; wxLogStatus(wxT("Copy file successfully.")); } else { wxLogStatus(wxT("Failed to copy file.")); } } *text1<<wxT("\n文件读取成功!\n"); }
从int byteCount开始至结束注释掉。下面将使用wxTextInputStream和wxTextOutputStream来重新实现该模块的功能以做比较。
void StreamAppFrame::OnStreamClick(wxCommandEvent& event) { wxString filename(wxT("streamMain.cpp")); wxString dummyfile(wxT("dummy.cpp")); wxFileInputStream inStream(filename); wxFileOutputStream outStream(dummyfile); /* int byteCount=inStream.GetLength(); static char buffer[1024*1024*1024]; wxString content; while(byteCount>0) { size_t bytesToRead=wxMin((size_t)sizeof(buffer),byteCount); if(inStream.Read((void*)buffer,bytesToRead).GetLastError()==wxSTREAM_NO_ERROR) { if(outStream.Write((void*)buffer,bytesToRead).GetLastError()==wxSTREAM_NO_ERROR) { content=wxString::FromUTF8(buffer,bytesToRead); byteCount-=bytesToRead; } *text1<<content; wxLogStatus(wxT("Copy file successfully.")); } else { wxLogStatus(wxT("Failed to copy file.")); } } *text1<<wxT("\n文件读取成功!\n"); */ ... }
wxTextInputStream和wxTextOutputStream的头文件为<wx/txtstrm.h>,将其加到源文件里来。
wxTextInputStream和wxTextOutputStream的构造函数分别需要传入wxFileInputStream/wxFFileInputStream ,wxFileOutputStream/wxFFileOutputStream的实例,然后输入流时可以用wxTextInputStream.ReadLine()来从流中读取一行,用wxTextOutputStream.WriteString(wxString&)来将字符串输出到终端,两种流都重载了流操作符<<和>>。
wxFFileInputStream fin(filename); wxFFileOutputStream fout(wxT("dummy1.cpp")); wxTextInputStream cin(fin); wxTextOutputStream cout(fout); while(1) { wxString got=cin.ReadLine(); if(fin.Eof() && got.empty()) break; *text1<<got<<wxT("\n"); cout<<got<<wxT("\n"); } text1->AppendText(wxT("搞定。")); wxLogStatus(wxT("读取并写入流完成。"));
添加上面的代码到OnStreamClick方法的最后,重新编译,运行,一切OK!但实现却简单了很多,是不是。
以下为OnStreamClick的完整代码:
void StreamAppFrame::OnStreamClick(wxCommandEvent& event) { wxString filename(wxT("streamMain.cpp")); wxString dummyfile(wxT("dummy.cpp")); wxFileInputStream inStream(filename); wxFileOutputStream outStream(dummyfile); /* int byteCount=inStream.GetLength(); static char buffer[1024*1024*1024]; wxString content; while(byteCount>0) { size_t bytesToRead=wxMin((size_t)sizeof(buffer),byteCount); if(inStream.Read((void*)buffer,bytesToRead).GetLastError()==wxSTREAM_NO_ERROR) { if(outStream.Write((void*)buffer,bytesToRead).GetLastError()==wxSTREAM_NO_ERROR) { content=wxString::FromUTF8(buffer,bytesToRead); byteCount-=bytesToRead; } *text1<<content; wxLogStatus(wxT("Copy file successfully.")); } else { wxLogStatus(wxT("Failed to copy file.")); } } *text1<<wxT("\n文件读取成功!\n"); */ wxFFileInputStream fin(filename); wxFFileOutputStream fout(wxT("dummy1.cpp")); wxTextInputStream cin(fin); wxTextOutputStream cout(fout); while(1) { wxString got=cin.ReadLine(); if(fin.Eof() && got.empty()) break; *text1<<got<<wxT("\n"); cout<<got<<wxT("\n"); } text1->AppendText(wxT("搞定。")); wxLogStatus(wxT("读取并写入流完成。")); }