How to find serial number of Android device?

Question

I need to use a unique ID for an Android app and I thought the serial number for the device would be a good candidate. How do I retrieve the serial number of an Android devi

Answer 1

I found the example class posted by @emmby above to be a great starting point. But it has a couple of flaws, as mentioned by other posters. The major one is that it persists the UUID to an XML file unnecessarily and thereafter always retrieves it from this file. This lays the class open to an easy hack: anyone with a rooted phone can edit the XML file to give themselves a new UUID.

I've updated the code so that it only persists to XML if absolutely necessary (i.e. when using a randomly generated UUID) and re-factored the logic as per @Brill Pappin's answer:

import android.content.Context;
import android.content.SharedPreferences;
import android.provider.Settings.Secure;
import android.telephony.TelephonyManager;

import java.io.UnsupportedEncodingException;
import java.util.UUID;

public class DeviceUuidFactory {
    protected static final String PREFS_FILE = "device_id.xml";
    protected static final String PREFS_DEVICE_ID = "device_id";

    protected static UUID uuid;

    public DeviceUuidFactory(Context context) {

        if( uuid ==null ) {
            synchronized (DeviceUuidFactory.class) {
                if( uuid == null) {
                    final SharedPreferences prefs = context.getSharedPreferences( PREFS_FILE, 0);
                    final String id = prefs.getString(PREFS_DEVICE_ID, null );

                    if (id != null) {
                        // Use the ids previously computed and stored in the prefs file
                        uuid = UUID.fromString(id);

                    } else {

                        final String androidId = Secure.getString(context.getContentResolver(), Secure.ANDROID_ID);

                        // Use the Android ID unless it's broken, in which case fallback on deviceId,
                        // unless it's not available, then fallback on a random number which we store
                        // to a prefs file
                        try {
                             if ( "9774d56d682e549c".equals(androidId) || (androidId == null) ) {
                                final String deviceId = ((TelephonyManager) context.getSystemService( Context.TELEPHONY_SERVICE )).getDeviceId();

                                if (deviceId != null)
                                {
                                    uuid = UUID.nameUUIDFromBytes(deviceId.getBytes("utf8"));
                                }
                                else
                                {
                                    uuid = UUID.randomUUID();

                                    // Write the value out to the prefs file so it persists
                                    prefs.edit().putString(PREFS_DEVICE_ID, uuid.toString() ).commit();
                                }
                            }
                            else
                            {
                                uuid = UUID.nameUUIDFromBytes(androidId.getBytes("utf8"));
                            } 
                        } catch (UnsupportedEncodingException e) {
                            throw new RuntimeException(e);
                        }



                    }

                }
            }
        }

    }


    /**
     * Returns a unique UUID for the current android device.  As with all UUIDs, this unique ID is "very highly likely"
     * to be unique across all Android devices.  Much more so than ANDROID_ID is.
     *
     * The UUID is generated by using ANDROID_ID as the base key if appropriate, falling back on
     * TelephonyManager.getDeviceID() if ANDROID_ID is known to be incorrect, and finally falling back
     * on a random UUID that's persisted to SharedPreferences if getDeviceID() does not return a
     * usable value.
     *
     * In some rare circumstances, this ID may change.  In particular, if the device is factory reset a new device ID
     * may be generated.  In addition, if a user upgrades their phone from certain buggy implementations of Android 2.2
     * to a newer, non-buggy version of Android, the device ID may change.  Or, if a user uninstalls your app on
     * a device that has neither a proper Android ID nor a Device ID, this ID may change on reinstallation.
     *
     * Note that if the code falls back on using TelephonyManager.getDeviceId(), the resulting ID will NOT
     * change after a factory reset.  Something to be aware of.
     *
     * Works around a bug in Android 2.2 for many devices when using ANDROID_ID directly.
     *
     * @see http://code.google.com/p/android/issues/detail?id=10603
     *
     * @return a UUID that may be used to uniquely identify your device for most purposes.
     */
    public UUID getDeviceUuid() {
        return uuid;
    }