Question

trying to get length of file which from local storage. File exists 100% (because I even tried to create it straight before getting the length (and checked it exists). Code is as simple as:

    try {
        InputStream is = new FileInputStream("errorlog2.txt");
        // Get the size of the file
        long length = file.length();
        // Close the input stream and return length
        is.close();
        return length;
    }
    catch (IOException e) {
         Log.w(BaseHelper.TAG_MAIN_ACTIVITY, "bad stuff: ", e);
        return 0;

in 100% cases it throws an exception. What might be the problem? What`s correct way to get length of local storage files?

thanks a lot!

UPDATE (full code) – file exists and readable, but no length 🙁

//creating file
String someFileName = "errlogtest.log";   
try {
   FileOutputStream fOut = openFileOutput(someFileName, Context.MODE_APPEND);
   OutputStreamWriter osw = new OutputStreamWriter(fOut);
   osw.write("dsgaadfg0df9g0sdf90sg9058349 sdf");
   osw.flush();
   osw.close();    
} catch (IOException ioe) {
   ioe.printStackTrace();
}

//reading file 

try {
  FileInputStream fileToOpen = openFileInput(someFileName);
  byte[] readerByte = new byte[fileToOpen.available()];
  while (fileToOpen.read(readerByte) != -1) {
  }
  String fileContents = new String(readerByte);
  fileContents.toString();
  // next line works fine
  Toast.makeText(getApplicationContext(), "FILE CONTENTS: " + fileContents, Toast.LENGTH_LONG).show();                      
  } catch (FileNotFoundException e) {
      Log.w("Reading file", "Unable to open file");
  } catch (IOException e) {
  Log.w("Reading file", "Error reading file");
  } 

 // trying to get length
 // simply not working:
 File file = new File(someFileName); 
 long length2 = file.length();
 Toast.makeText(getApplicationContext(),    "FILE LENGTH:" + length2, Toast.LENGTH_LONG).show();

 // shows zero and filenotfoundexception: /errlogtest.log
try {
  RandomAccessFile raffile = new RandomAccessFile(new File(someFileName), "r"); 
  long length = raffile.length();
  Toast.makeText(getApplicationContext(),   "FILE LENGTH:" + length, Toast.LENGTH_LONG).show();
catch (IOException e) {
  Log.w("Reading file", "Error reading file", e);
}

help please

Answer 1

Depending on where you are creating the file then you’ll need to provide a full path and not just a file name.

For example, if the file is being created using Context.openFileOutput(...) then you would use something like…

long length = new File(getFilesDir().getAbsolutePath() + "/errorlog2.txt").length();