How to make a two-language application by changing the language in the settings menu? Android studio

I would like to do this manually through a click, Portuguese or English Language. and fetch the correct string.

public boolean onCreateOptionsMenu (Menu menu) {         getMenuInflater (). inflate (R.menu.menu_main, menu);         return true;     }

public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getItemId() == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}