PreferenceActivity provides a convenient way to implement system settings screens in Android applications. Instead of manually creating configuration files and handling data persistence, PreferenceActivity manages these details automatically through SharedPreferences.

First, create a XML folder in the res directory and add a configuraton file named preferences.xml.

preferences.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >

    <CheckBoxPreference
        android:key="auto_sync_key"
        android:summary="Enable automatic synchronization"
        android:summaryOff="Automatic sync disabled"
        android:summaryOn="Automatic sync enabled"
        android:title="Auto Sync" />

    <PreferenceCategory android:title="Network Settings" >
        <CheckBoxPreference
            android:key="mobile_data_key"
            android:summary="Allow downloads over mobile network"
            android:summaryOff="Mobile data downloads disabled"
            android:summaryOn="Mobile data downloads enabled"
            android:title="Download via Mobile Data" />
    </PreferenceCategory>

    <EditTextPreference
        android:dialogTitle="Enter username"
        android:key="username_key"
        android:negativeButtonText="Cancel"
        android:positiveButtonText="Save"
        android:summary="Your display name"
        android:title="Display Name" />

    <ListPreference
        android:dialogTitle="Select theme"
        android:entries="@array/theme_options"
        android:entryValues="@array/theme_values"
        android:key="theme_key"
        android:positiveButtonText="OK"
        android:summary="Application theme"
        android:title="Theme" />

</PreferenceScreen>

For ListPreference, define the available options in strings.xml under the values folder.

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_title">Settings Demo</string>
    <string-array name="theme_options">
        <item>Light</item>
        <item>Dark</item>
        <item>System Default</item>
    </string-array>
    <string-array name="theme_values">
        <item>light</item>
        <item>dark</item>
        <item>system</item>
    </string-array>
</resources>

Create a simple main layout with a button to navigate to the settings screen.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/app_title"
        android:textSize="20sp" />

    <Button
        android:id="@+id/open_settings_btn"
        android:onClick="navigateToSettings"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="Open Settings" />

</LinearLayout>

MainActivity.java

package com.example.settingsdemo;

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
        String themeValue = preferences.getString("theme_key", "system");
        Toast.makeText(this, "Current theme: " + themeValue, Toast.LENGTH_SHORT).show();
    }
    
    public void navigateToSettings(View view) {
        Intent intent = new Intent(this, SettingsActivity.class);
        startActivity(intent);
    }
}

SettingsActivity.java

package com.example.settingsdemo;

import android.os.Bundle;
import android.preference.PreferenceActivity;

public class SettingsActivity extends PreferenceActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.preferences);
    }
}

To retrieve saved preference values throughout the application, use PreferenceManager.getDefaultSharedPreferences() with the appropriate key names defined in you're preferences XML file.