wireguard-android/app/src/main/java/com/wireguard/android/activity/SettingsActivity.java

package com.wireguard.android.activity;

import android.app.Activity;
import android.os.Bundle;
import android.preference.PreferenceFragment;

import com.wireguard.android.R;

/**
 * Interface for changing application-global persistent settings.
 */

public class SettingsActivity extends Activity {
    @Override
    protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getFragmentManager().findFragmentById(android.R.id.content) == null) {
            getFragmentManager().beginTransaction()
                    .add(android.R.id.content, new SettingsFragment())
                    .commit();
        }
    }

    public static class SettingsFragment extends PreferenceFragment {
        @Override
        public void onCreate(final Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            addPreferencesFromResource(R.xml.preferences);
        }
    }
}