Saving and retrieving spinner value with sharedpreferences

I have a spinner. I want to save its value in saveFile() and retrieve the same on calling readFile() using sharedpreferences. I haven't got the right way to do it yet.

    spinner = (Spinner) findViewById(R.id.spinner);
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
            R.array.countries_array, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(adapter);
    public void saveFile(){
            SharedPreferences sharedPref = getSharedPreferences(FileName,Context.MODE_PRIVATE);
            SharedPreferences.Editor editor=sharedPref.edit();
     }
    public void readFile(){
            SharedPreferences sharedPref = getSharedPreferences(FileName,Context.MODE_PRIVATE);
    }

Try this

     public void saveFile(){
            SharedPreferences sharedPref = getSharedPreferences(FileName,Context.MODE_PRIVATE);
            SharedPreferences.Editor editor=sharedPref.edit();
            editor.putInt("spinnerValue",spinner.getSelectedItemPosition());
            editor.apply();
     }

     public void readFile(){
            SharedPreferences sharedPref = getSharedPreferences(FileName,Context.MODE_PRIVATE);
            int index = sharedPref.getInt("spinnerValue",0);
            spinner.setSelection(index);
     }