Question

I want to set file length to zero. i used following code

      try 
      {
          new RandomAccessFile(file,"rw").setLength(0);
      } 
      catch (FileNotFoundException e1) 
      {
          // TODO Auto-generated catch block
          Log.i("Exception caught ==> ", e1.toString());
          e1.printStackTrace();
      } 
      catch (IOException e) 
      {
          // TODO Auto-generated catch block
          Log.i("Exception caught ==> ", e.toString());
          e.printStackTrace();
      }

The problem, if again anything i write in the file means, it showing some speacial character in the file like AAAAAAAAAAAA and followed my content. Please give me some suggestion.

Answer 1

The issue may be in read buffer. if you have want to read a file which has 10 bytes data and you have created a byte[] of 15 then you wil get extra null there. better create a byte array of size same as file length. also after getting string you can trim() the data

I have tried with the following code but didnot get any issue.

Sample Code

RandomAccessFile ram = null;
    byte[] mydata = null;
    try 
    {
        System.out.println("...rrunning my app...");
        String str =Environment.getExternalStorageDirectory().getAbsolutePath()+"/myfile.txt";
//      File f = new File(str);
        ram =new RandomAccessFile(str,"rw");
        ram.setLength(0);
        ram.write("i am fine".getBytes());
        System.out.println("...file length..."+ram.length());
        mydata = new byte[(int) ram.length()];
        ram.close();
        RandomAccessFile ram1 =new RandomAccessFile(str,"rw");
        ram1.read(mydata);
        System.out.println("...data present in 11file..."+new String(mydata));

    } 
    catch (Exception e1) 
    {
        // TODO Auto-generated catch block
        Log.i("Exception caught ==> ", e1.toString());
        e1.printStackTrace();
    }