Java tutorial
//package com.java2s; import android.content.Context; import android.content.SharedPreferences; import android.media.RingtoneManager; import java.util.Random; public class Main { public static void changeRingtone(Context context) { SharedPreferences sharedPreferences = context.getSharedPreferences("randomizer", Context.MODE_PRIVATE); if (!sharedPreferences.getBoolean("active", false)) { return; } // END if RingtoneManager ringtoneManager = new RingtoneManager(context); Random random = new Random(System.currentTimeMillis()); int count = random.nextInt(ringtoneManager.getCursor().getCount()); RingtoneManager.setActualDefaultRingtoneUri(context, RingtoneManager.TYPE_RINGTONE, ringtoneManager.getRingtoneUri(count)); } }