xcode 使用 COCOS2D-X 进行文件 I/O

File I/O using COCOS2D-X

提问by alxcyl

I'm trying to load up a Comma Separated file called POSDATA.GAMEDATA. I've looked up several places on the internet and it turns out I need to do some tweaking and / or a different class.

我正在尝试加载一个名为POSDATA.GAMEDATA. 我在互联网上查了几个地方，结果我需要做一些调整和/或不同的类。

I tried using ifstream. However, it cannot open the file. Xcode 4.3.2 cannot seem to find my POSDATA.GAMEDATAfile. I also tried to make the file using ofstreambut when I use open()in both cases, the file is not opened.

我尝试使用ifstream. 但是，它无法打开文件。Xcode 4.3.2 似乎找不到我的POSDATA.GAMEDATA文件。我也尝试使用该文件，ofstream但是当我open()在这两种情况下使用时，该文件都没有打开。

My code is something like this:

我的代码是这样的：

using namespace std;
void FileLoader::loadFile( string p_WhichFile ) {
   // Local Variables
   string thisLine;

   // Open POSDATA.GAMEDATA
   ifstream dataStream;
   dataStream.open( p_WhichFile.c_str( ) );

   // Check if file is opened
   if ( !dataStream ) {
      cerr << "[ ERROR ] Cannot load file:" << p_WhichFile.c_str( ) << endl;
      exit( 1 );
   }

   // Get lines of strings
   while ( getline( dataStream, thisLine ) ) {
      fileContents.push_back( thisLine ); // fileContents is a vector< string > object
   }

   dataStream.close( );
   cout << "[ NOTICE ] Finished reading file" << p_WhichFile << endl;
}

I've seen CCFileUtilsbut I can't seem to get how to use it.

我见过，CCFileUtils但我似乎不知道如何使用它。

EDIT: I've tried supplying the absolute path ( /Users/LanceGray/Documents/LanceDev/COCOS2DX/cocos2dx/TestGame/Data/POSDATA.GAMEDATA) and it worked. However, I cannot do this since the game is supposed to be used in iOS devices and Android, so the path is not always the same on each device. Any help will be grealy appreciated.

编辑：我试过提供绝对路径 ( /Users/LanceGray/Documents/LanceDev/COCOS2DX/cocos2dx/TestGame/Data/POSDATA.GAMEDATA) 并且它有效。但是，我不能这样做，因为该游戏应该在 iOS 设备和 Android 中使用，因此每个设备上的路径并不总是相同的。任何帮助将不胜感激。

回答by alxcyl

I got working by using CCFileUtils( )::sharedFileUtils( ) -> fullPathFromRelativePath( "POSDATA.GAMEDATA" );

我开始使用 CCFileUtils( )::sharedFileUtils( ) -> fullPathFromRelativePath( "POSDATA.GAMEDATA" );

A more detailed explanation:

更详细的解释：

1. Add the files that you need in the Project by going to the Project Tree on the left and Right-click -> Add Files. What I did was I added a new folder called Dataon the same level as the Resourcesand Classesfolders and placed my POSDATA.GAMEDATAfile there. In Xcode, I added a new group and added that file in that group.
2. Then I used ifstreamto open the file.
3. When opening the file, use CCFileUtils( )::sharedFileUtils( ) -> fullPathFromRelativePath( )to get the absolute path of the file. Supply the file name on the fullPathFromRelativePath( )as argument.
4. Try to run it and it should work fine.

1. 通过转到左侧的项目树和 ，在项目中添加您需要的文件Right-click -> Add Files。我所做的是添加了一个Data与Resources和Classes文件夹处于同一级别的新文件夹，并将我的POSDATA.GAMEDATA文件放在那里。在 Xcode 中，我添加了一个新组并将该文件添加到该组中。
2. 然后我用来ifstream打开文件。
3. 打开文件时，使用CCFileUtils( )::sharedFileUtils( ) -> fullPathFromRelativePath( )获取文件的绝对路径。在fullPathFromRelativePath( )as 参数中提供文件名。
4. 尝试运行它，它应该可以正常工作。

A small example:

一个小例子：

// FileReader.h
#include "cocos2d.h"

using namespace std;
using namespace cocos2d;

class FileReader {
private:
   vector< string > mFileContents;

public:
   FileReader( string pFileName, char pMode = 'r' );
};

// FileReader.cpp
#include "FileReader.h"
#include <fstream>
#include "cocos2d.h"

using namespace cocos2d;
using namespace std;

FileReader::FileReader( string pFileName, char pMode ) {
   // Create input file stream
   ifstream inputStream;
   string thisLine;

   // Open file
   inputStream.open( CCFileUtils( )::sharedFileUtils( ) -> fullPathFromRelativePath( pFileName ).c_str( ) );

   // Check if it is open
   if ( !inputStream.is_open( ) ) {
      cerr << "[ ERROR ] Cannot open file: " << pFileName.c_str( ) << endl;
      exit( 1 );
   }

   while ( getline( inputStream, thisLine ) ) {
      // Put all lines in vector
      mFileContents.push_back( thisLine );
   }

   inputStream.close( );
   cout << "[ NOTICE ] Finished opening file: " << pFileName.c_str( ) << endl;
}

This class will load a file with the name pFileNameand place it on its member variable mFileContents. ( Note that it should have a public getfunction like vector< string > getFileContents( )to access the mFileContentsbecause it is private)

此类将加载具有该名称的文件pFileName并将其放置在其成员变量中mFileContents。（请注意，它应该有一个public get类似于vector< string > getFileContents( )访问的功能，mFileContents因为它是private）

EDIT: The above sample will work on iOS, however, it won't on Android devices. So to fix this, instead of using ifstream, use CCFileUtils::sharedUtils( ) -> getFileData( )instead. In conjunction with CCFileUtils::sharedUtils( ) -> fullPathFromRelativePath( ), we will be able to achieve our goal of reading a plain text file that works on both iOS and Android.

编辑：上述示例适用于 iOS，但不适用于 Android 设备。所以要解决这个问题，不要使用ifstream，CCFileUtils::sharedUtils( ) -> getFileData( )而是使用。结合CCFileUtils::sharedUtils( ) -> fullPathFromRelativePath( )，我们将能够实现读取适用于 iOS 和 Android 的纯文本文件的目标。

The FileReaderclass would then be like this:

在FileReader随后类将是这样的：

// FileReader.cpp
#include "FileReader.h"
#include <fstream>
#include "cocos2d.h"

using namespace cocos2d;
using namespace std;

FileReader::FileReader( string pFileName, char pMode ) {
   // Initialize variables needed
   unsigned long fileSize = 0;
   unsigned char * fileContents = NULL;
   string thisLine, result, fullPath, contents;

   // Get absolute path of file
   fullPath = CCFileUtils::sharedFileUtils( ) -> fullPathFromRelativePath( pFileName.c_str( ) );

   // Get data of file
   fileContents = CCFileUtils::sharedFileUtils( ) -> getFileData( fullPath.c_str( ) , "r", &fileSize );
   contents.append( ( char * ) fileContents );

   // Create a string stream so that we can use getline( ) on it
   istringstream fileStringStream( contents );

   // Get file contents line by line
   while ( getline( fileStringStream, thisLine ) ) {
      // Put all lines in vector
      mFileContents.push_back( thisLine );
   }

   // After this, mFileContents will have an extra entry and will have the value '\x04'.
   // We should remove this by popping it out the vector.
   mFileContents.pop_back( );

   // Delete buffer created by fileContents. This part is required.
   if ( fileContents ) {
      delete[ ] fileContents;
      fileContents = NULL;
   }

   // For testing purposes
   cout << "[ NOTICE ] Finished opening file: " << pFileName.c_str( ) << endl;
}

回答by m.ding

// For versions less than v2.0.1
// The version I am using is 0.12.0
unsigned long fileSize = 0;
char* pBuffer = CCFileUltils::getFileData("relative_path","r",&fileSize);
CCLOG("Data is %s",pBuffer);

回答by thphong

You can reference from Cocos's wiki Read/write file in cocos2d

你可以参考 Cocos 的 wiki Read/write file in cocos2d