android java create file in specific folder

try {
    String rootPath = Environment.getExternalStorageDirectory()
            .getAbsolutePath() + "/MyFolder/";
    File root = new File(rootPath);
    if (!root.exists()) {
        root.mkdirs();
    }
    File f = new File(rootPath + "mttext.txt");
    if (f.exists()) {
        f.delete();
    }
    f.createNewFile();

    FileOutputStream out = new FileOutputStream(f);

    out.flush();
    out.close();
} catch (Exception e) {
    e.printStackTrace();
}