SettingsFragment Class

package androidlab.exercise6_1.gui;

import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.Preference;
import android.preference.Preference.OnPreferenceChangeListener;
import android.preference.PreferenceFragment;
import androidlab.exercise6_1.R;
import androidlab.exercise6_1.data.Settings;

public class SettingsFragment extends PreferenceFragment implements OnPreferenceChangeListener {

  SharedPreferences settings;
  SharedPreferences.Editor setEditor;

  // The different Preference Types from the Layout
  Preference APP_ENABLED;
  Preference SMS_ENABLED;
  Preference NOT_ENABLED;
  Preference LED_ENABLED;
  Preference CEN_ENABLED;

  @Override
  public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.layout.settings_layout);

    // Setting up the Preferences with their corresponding Keys
    APP_ENABLED = findPreference(Settings.KEY_ENABLE);
    SMS_ENABLED = findPreference(Settings.KEY_SMS);
    NOT_ENABLED = findPreference(Settings.KEY_NOT);
    LED_ENABLED = findPreference(Settings.KEY_LED);
    CEN_ENABLED = findPreference(Settings.KEY_CENTER);

    // Setting Listeners
    APP_ENABLED.setOnPreferenceChangeListener(this);
    SMS_ENABLED.setOnPreferenceChangeListener(this);
    NOT_ENABLED.setOnPreferenceChangeListener(this);
    LED_ENABLED.setOnPreferenceChangeListener(this);
    CEN_ENABLED.setOnPreferenceChangeListener(this);
  }

  @Override
  public boolean onPreferenceChange(Preference preference, Object newValue) {

    settings = getPreferenceManager().getSharedPreferences();
    setEditor = settings.edit();

    // Keys might be used by other Activities/ classes as well so I access them statically
    if (preference.getKey().equals(Settings.KEY_ENABLE)) {
      setEditor.putBoolean(Settings.KEY_ENABLE, preference.getKey().equals(Settings.KEY_ENABLE));
    }
    else if (preference.getKey().equals(Settings.KEY_SMS)) {
      setEditor.putBoolean(Settings.KEY_SMS, preference.getKey().equals(Settings.KEY_SMS));
    }
    else if (preference.getKey().equals(Settings.KEY_NOT)) {
      setEditor.putBoolean(Settings.KEY_NOT, preference.getKey().equals(Settings.KEY_NOT));
    }
    else if (preference.getKey().equals(Settings.KEY_LED)) {
      setEditor.putBoolean(Settings.KEY_LED, preference.getKey().equals(Settings.KEY_LED));
    }
    else if (preference.getKey().equals(Settings.KEY_CENTER)) {
      setEditor.putBoolean(Settings.KEY_CENTER, preference.getKey().equals(Settings.KEY_CENTER));
    }

    setEditor.commit();

    System.out.println(settings.getAll());
    return true;
  }
}