simple preferences with java

MainActivity.java

package com.mostafaanter.preferenceswithjava;

import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.Layout;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;

import utils.UIHelper;

public class MainActivity extends AppCompatActivity {
    public static String LOGTAG = "information";
    public static String USERNAME = "userName";

    private SharedPreferences settings;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        settings = getPreferences(MODE_PRIVATE);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
    public void set_preferences(View view) {
        Log.i(LOGTAG, "clicked set");
        SharedPreferences.Editor editor = settings.edit();
        String prefValue = UIHelper.getText(this, R.id.editText1);
        editor.putString(USERNAME, prefValue);
        editor.commit();
        UIHelper.displayText(this, R.id.text1, "Preference Saved");

    }

    public void show_preferences(View view) {
        Log.i(LOGTAG,"clicked show");
        String prefValue = settings.getString(USERNAME, "username not found!");
        UIHelper.displayText(this, R.id.text1, prefValue);
    }

}