AppPreferences

public class PreferencesHelper {

    private static final String TAG = "PreferencesHelper";
    private Context mApplicationContext;
    private static PreferencesHelper sInstance;
    private static final boolean PREFERENCES_ENABLED = true;
    private static SharedPreferences prefs;

    public static PreferencesHelper getInstance(Context context) {
        if (!PREFERENCES_ENABLED) {
            return sEmptyPreferencesHelper;
        }

        if (sInstance == null) {
            if (context == null) {
                return sEmptyPreferencesHelper;
            }
            sInstance = new PreferencesHelper(context);
        }

        return sInstance;
    }

    private PreferencesHelper(Context context) {
        if (context == null) {
            // This should only occur for the empty Preferences Helper object.
            return;
        }

        mApplicationContext = context.getApplicationContext();
        prefs = PreferenceManager.getDefaultSharedPreferences(mApplicationContext);

        Log.d(TAG, "Initializing Shared Preferences");

    }

    public String getValue(String key, String s) {
        return prefs.getString(key, s);
    }

    public void setValue(String key, String value) {
        prefs.edit().putString(key, value);
    }

    public int getValue(String key, int i) {
        return prefs.getInt(key, i);
    }

    public boolean getValue(String key, boolean b) {
        return prefs.getBoolean(key, b);
    }

    /**
     * Empty instance for use when Preferences is disabled or there was no Context available.
     */
    private static PreferencesHelper sEmptyPreferencesHelper = new PreferencesHelper(null) {
        @Override
        public String getValue(String key, String s) { return s; }

        @Override
        public void setValue(String key, String value) {}
    };
}