Java tutorial
//package com.java2s; import android.content.Context; import android.provider.Settings.Secure; public class Main { protected static String getFileKeyName(String extension, Context context) { String keyName = null; keyName = String.valueOf(System.currentTimeMillis()); String deviceId = Secure.getString(context.getContentResolver(), Secure.ANDROID_ID); keyName = deviceId + "_" + keyName + "." + extension; return keyName; } }