There does not seem to be any Android manifest permission that needs to be set for file io.
public class Device extends Activity {
private static final Configuration config = new Configuration();
...
private boolean applyMenuChoice(MenuItem item) {
switch (item.getItemId()) {
...
case R.id.menuSave:
...
configuration.modify(name, to, from, user);
configuration.write();
...
public class Configuration extends Activity {
private final static String CONFIG = "config.txt";
private static StringBuilder config = new StringBuilder();
...
public void write() {
try {
FileOutputStream fos = openFileOutput(CONFIG, Context.MODE_PRIVATE);
fos.write(config.toString().getBytes());
...