Android Country preference using 100% native resources, with no need to read countries from external files. Automatically sorted and translated.

CountryPreference.java

package <your_package>;

import android.content.Context;
import android.content.SharedPreferences;
import android.util.AttributeSet;

/* You can use default ListPreference if you prefer.
   Got this lib from <link>https://github.com/afollestad/material-dialogs</link>
*/
import com.afollestad.materialdialogs.prefs.MaterialListPreference;
import com.br.batendomacrosandroid.utils.Util;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeMap;
import java.util.TreeSet;

public class CountryPreference extends MaterialListPreference {

    public CountryPreference(Context context) {
        super(context);
        this.init();
    }

    public CountryPreference(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.init();
    }

    private void init() {
        Locale[] locales = Locale.getAvailableLocales();

        Map<String, String> unsortedCountriesMap = new HashMap<>();

        for (Locale locale : locales) {
            String countryCode = locale.getCountry();
            String country = locale.getDisplayCountry();

            if (country.trim().length() > 0 && unsortedCountriesMap.get(countryCode) == null) {
                unsortedCountriesMap.put(country, countryCode);
            }
        }

        Map<String, String> sortedCountriesMap = new TreeMap<>(unsortedCountriesMap);

        String[] countriesCodesArray = new String[unsortedCountriesMap.size()];
        String[] countriesNamesArray = new String[unsortedCountriesMap.size()];

        this.setEntryValues(sortedCountriesMap.values().toArray(countriesCodesArray));
        this.setEntries(sortedCountriesMap.keySet().toArray(countriesNamesArray));
    }
}

/* To use on your pref.xml */
/***************************************************
<<your_package>.CountryPreference
            android:defaultValue=""
            android:key="user_country"
            android:negativeButtonText="@null"
            android:positiveButtonText="@null"
            android:summary=""
            android:title="@string/pref_country"/>
/**************************************************/


/* Here's an util method to get a Country name to set on your PreferencesFragment */

/****************************************
private String getCountryNameByCode() {
   String currentPreferenceValue = userSharedPreferences.getString(Constants.PREFS_USER_COUNTRY, Constants
       .EMPTY);
   String countryCode = currentPreferenceValue.equals(Constants.EMPTY) ? Locale.getDefault().getCountry() : currentPreferenceValue;
   Locale loc = new Locale(Constants.EMPTY, countryCode);
   return loc.getDisplayCountry();
}
****************************************/