各位帮我看看这个小程序,在java编辑器可以编译运行获取到数据,把方法里面的代码移植到一个安卓小项目就无法获取到文件里面的内容,各位大神,帮帮我这新手...

package com.caishaoze.test;
import java.io.*;  
  
public class FileOpenString{  
     public String readFile(String fileName) {  
        String output = "";   
          
        File file = new File(fileName);  
             
        if(file.exists()){  
            if(file.isFile()){  
                try{  
                    BufferedReader input = new BufferedReader (new FileReader(file));  
                    StringBuffer buffer = new StringBuffer();  
                    String text;  
                         
                    while((text = input.readLine()) != null)  
                        buffer.append(text +"/n");  
                         
                    output = buffer.toString();                      
                }  
                catch(IOException ioException){  
                    System.err.println("File Error!");  
  
                }  
            }  
            else if(file.isDirectory()){  
                String[] dir = file.list();  
                output += "Directory contents:/n";  
                  
                for(int i=0; i<dir.length; i++){  
                    output += dir[i] +"/n";  
                }  
            }  
        }  
        else{  
            System.err.println("Does not exist!");  
        }  
       
        return output;  
     } 
     public static void main(String[] args){
      FileOpenString f=new FileOpenString();
      String str=f.readFile("c:\\ffff.txt");
      System.out.print(str);
     
      }
      }