Question

I have been experimenting with writing to sdcard storage in my Android application (Target API 11)

I have been successful in creating the Directory in the following code called “BPAExp_data” but it does not create a new file at all. I’m stumped as to why since it does not show up in the logcat!!.

Here is my onCreate() method

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_text_logger);
    String data = "asdfghjkl.."

    //The filename of the log file
    filename = getIntent().getExtras().getString("Filename");

    //Save Test data button
    Button saveData = (Button)findViewById(R.id.saveDataButton);
    saveData.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View arg0) {
        // Save Data in file and go back to home screen
        addtoKeyLogFile(data);              

        //Make intent for the Main Activity screen
        Intent main_intent = new Intent(TextLogger.this, MainActivity.class);
        startActivity(main_intent);
        }
    });

This is my method called addKeyLogFile()

    public void addtoKeyLogFile(String data){       
    FileOutputStream f = null;
    File data_file;
    try {
        File sdCard = Environment.getExternalStorageDirectory();
        File dir = new File (sdCard.getAbsolutePath() + "/BPAExp_data");
        dir.mkdirs();
        data_file = new File(dir, filename);
        f = new FileOutputStream(data_file);
        // if file doesn't exists, then create it
        if (!data_file.exists()) {
            data_file.createNewFile();
            Toast.makeText(TextLogger.this, "File GOT CREATED!", Toast.LENGTH_SHORT).show();
        }

        // get the content in bytes
        byte[] dataInBytes = data.getBytes();

        f.write(dataInBytes);
        f.flush();
        f.close();

    } catch (FileNotFoundException e) {
        e.printStackTrace();
        Log.d("TextLogger onCreate: ", e.getMessage());
    } catch (IOException e) {
        e.printStackTrace();
        Log.d("TextLogger onCreate: ", e.getMessage());
    } finally {
        try {
            if (f != null) {
                f.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

I have Located that the problem lies in or near the

    f = new FileOutputStream(data_file);

because when I put a toast message after that it is never executed BUT if I put a toast before it, it is executed! Also the intent after that works perfectly fine!
But I do NOT understand, why is it not working?

Thanks for any help anyone can provide!

Answer 1

File has multiple constructors. One take as parameters a File and String:

File dir = new File (sdCard , "BPAExp_data");
dir.mkdirs();
data_file = new File(dir, filename);

What’s the value of filename ?

remove those lines:

   if (!data_file.exists()) {
          data_file.createNewFile();
          Toast.makeText(TextLogger.this, "File GOT CREATED!", Toast.LENGTH_SHORT).show();
   }

File will be created when you stop writing the file.

 f.close();

you call it twice. Leave it only inside the finally block

All in all, are you sure that you have something to write?

byte[] dataInBytes = data.getBytes();

is the length of dataInBytes > 0 ?