public void Write(String data) {
    File dataDirectory = context.getExternalFilesDir(Environment.getDataDirectory().getAbsolutePath());
    ;
    /*
    dataDirectory = new File(dataDirectory.getAbsolutePath() + "/" + DIR_NAME);
    if (!dataDirectory.exists()) {
        dataDirectory.mkdir();
    }
    */

    Log.d("file", "mkdir is " + dataDirectory.exists());

    File file = new File(dataDirectory, "log.txt");
    try {
        if (!file.exists()) {
            file.createNewFile();
        }

        Log.d("file", "file creating is " + file.exists());

        Date date = new Date();

        //BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(file));
        FileWriter fileWriter = new FileWriter(file);
        StringBuilder stringBuilder = new StringBuilder(data);
        stringBuilder.insert(0, date);
        fileWriter.append(stringBuilder.toString() + "rn");
        fileWriter.close();
        /*
        bufferedWriter.append(stringBuilder.toString()+"rn");;
        bufferedWriter.close();
        */
    } catch (Exception e) {
        e.printStackTrace();
    }