How can I get the "network" time, (from the "Automatic" setting called "Use network-provided values"), NOT the time on the phone?

Question

I would like in my application to find a way to synch the date and time with something given by an external source.

I don't want to use the phone time because I might get a difference of maybe 5 minutes around real time. and 5 minutes extra or less = 10 minutes!

I have heard about time information in the GPS satellites or in Network antennas.

I have tried with System.getCurrentTime but i get the current the of the device, so, if my device is set up 5 minutes earlier, it display the wrong time.

EDIT

To make a short question: how can I get this time?

Gomes

Duplicates this question: #7157684 – Hebron

Answer 1

I didn't know, but found the question interesting. So I dug in the android code... Thanks open-source :)

The screen you show is DateTimeSettings. The checkbox "Use network-provided values" is associated to the shared preference String KEY_AUTO_TIME = "auto_time"; and also to Settings.System.AUTO_TIME

This settings is observed by an observed called mAutoTimeObserver in the 2 network ServiceStateTrackers: GsmServiceStateTracker and CdmaServiceStateTracker.

Both implementations call a method called revertToNitz() when the settings becomes true. Apparently NITZ is the equivalent of NTP in the carrier world.

Bottom line: You can set the time to the value provided by the carrier thanks to revertToNitz(). Unfortunately, I haven't found a mechanism to get the network time. If you really need to do this, I'm afraid, you'll have to copy these ServiceStateTrackers implementations, catch the intent raised by the framework (I suppose), and add a getter to mSavedTime.

Morgan

Ok, so the short answer is... I will never be able to do that :-p. Thank a lot for the time you spent and enjoy the bounty! – Gomes

Answer 2

Get the library from http://commons.apache.org/net/download_net.cgi

//NTP server list: http://tf.nist.gov/tf-cgi/servers.cgi
public static final String TIME_SERVER = "time-a.nist.gov";

public static long getCurrentNetworkTime() {
    NTPUDPClient timeClient = new NTPUDPClient();
    InetAddress inetAddress = InetAddress.getByName(TIME_SERVER);
    TimeInfo timeInfo = timeClient.getTime(inetAddress);
    //long returnTime = timeInfo.getReturnTime();   //local device time
    long returnTime = timeInfo.getMessage().getTransmitTimeStamp().getTime();   //server time

    Date time = new Date(returnTime);
    Log.d(TAG, "Time from " + TIME_SERVER + ": " + time);

    return returnTime;
}

getReturnTime() is same as System.currentTimeMillis().

getReceiveTimeStamp() or getTransmitTimeStamp() method should be used.

You can see the difference after setting system time to 1 hour ago.

local time :
System.currentTimeMillis()
timeInfo.getReturnTime()
timeInfo.getMessage().getOriginateTimeStamp().getTime()

NTP server time :
timeInfo.getMessage().getReceiveTimeStamp().getTime()
timeInfo.getMessage().getTransmitTimeStamp().getTime()

Waterworks

This a usefull answer, but that require an internet connexion which is not the case of the network time used in Android settings – Gomes

what would be library to compile for android studio? – Stubbs

does this require INTERNET PERMISSIONS? – Nicolnicola

Answer 3

Try this snippet of code:

String timeSettings = android.provider.Settings.System.getString(
                this.getContentResolver(),
                android.provider.Settings.System.AUTO_TIME);
        if (timeSettings.contentEquals("0")) {
            android.provider.Settings.System.putString(
                    this.getContentResolver(),
                    android.provider.Settings.System.AUTO_TIME, "1");
        }
        Date now = new Date(System.currentTimeMillis());
        Log.d("Date", now.toString());

Make sure to add permission in Manifest

<uses-permission android:name="android.permission.WRITE_SETTINGS"/>

Afterburning

It's not a solution, see code - it just turn on AUTO_TIME, but system need some time to synchronize current time. Moreover, user may not want this auto-time. For example there is a bug in my timezone, and it shows +1 hour time. – Irwinirwinn

This doesn't works anymore. As for API level 18 and above "System.AUTO_TIME" is moved to "Global.AUTO_TIME" and to access that we need "WRITE_SECURE_SETTINGS" permission, which is accessible only by system apps. – Daron

Answer 4

NITZ is a form of NTP and is sent to the mobile device over Layer 3 or NAS layers. Commonly this message is seen as GMM Info and contains the following informaiton:

Certain carriers dont support this and some support it and have it setup incorrectly.

LAYER 3 SIGNALING MESSAGE

Time: 9:38:49.800

GMM INFORMATION 3GPP TS 24.008 ver 12.12.0 Rel 12 (9.4.19)

M Protocol Discriminator (hex data: 8)

(0x8) Mobility Management message for GPRS services

M Skip Indicator (hex data: 0) Value: 0 M Message Type (hex data: 21) Message number: 33

O Network time zone (hex data: 4680) Time Zone value: GMT+2:00 O Universal time and time zone (hex data: 47716070 70831580) Year: 17 Month: 06 Day: 07 Hour: 07 Minute :38 Second: 51 Time zone value: GMT+2:00 O Network Daylight Saving Time (hex data: 490100) Daylight Saving Time value: No adjustment

Layer 3 data: 08 21 46 80 47 71 60 70 70 83 15 80 49 01 00

Simmers

Answer 5

This seemed to work for me:

LocationManager locMan = (LocationManager) activity.getSystemService(activity.LOCATION_SERVICE);
long networkTS = locMan.getLastKnownLocation(LocationManager.NETWORK_PROVIDER).getTime();

Working on Android 2.2 API (Level 8)

Phenoxide

This solution always returns me the same time. – Hereunto

You are only getting the last location time. – Oisin

Of course it is getting same time. The solution clearly gets last known location and uses time bundled with it. (see developer.android.com/reference/android/location/…). Unless your location is changed every moment and your device has it, it will always show wrong time. Clearly not a solution. – Soldierly

this is an interesting solution because it requires that you move constantly in order for the time to get refreshed, thus making you do more activity and improving your health. I would say this is a good solution for runners or people who want to get challenged. someone asks you what time is it? no problem, just let me run a few hundred meters and I'll come back and tell you. I understand people who upvoted this answer. – Bifoliolate

Answer 6

Now you can get time for the current location but for this you have to set the system's persistent default time zone.setTimeZone(String timeZone) which can be get from

Calendar calendar = Calendar.getInstance();
 long now = calendar.getTimeInMillis();
 TimeZone current = calendar.getTimeZone();

setAutoTimeEnabled(boolean enabled)

Sets whether or not wall clock time should sync with automatic time updates from NTP.

TimeManager timeManager = TimeManager.getInstance();
 // Use 24-hour time
 timeManager.setTimeFormat(TimeManager.FORMAT_24);

 // Set clock time to noon
 Calendar calendar = Calendar.getInstance();
 calendar.set(Calendar.MILLISECOND, 0);
 calendar.set(Calendar.SECOND, 0);
 calendar.set(Calendar.MINUTE, 0);
 calendar.set(Calendar.HOUR_OF_DAY, 12);
 long timeStamp = calendar.getTimeInMillis();
 timeManager.setTime(timeStamp);

I was looking for that type of answer I read your answer but didn't satisfied and it was bit old. I found the new solution and share it. :)

For more information visit: https://developer.android.com/things/reference/com/google/android/things/device/TimeManager.html

Quieten

How can we use it for an Android Mobile App? This is part of Android Things. – Millrun

Answer 7

I read that this

LocationManager locMan = (LocationManager) activity.getSystemService(activity.LOCATION_SERVICE);
long time = locMan.getLastKnownLocation(LocationManager.NETWORK_PROVIDER).getTime();

provides correct time, without internet at the cost of some blocking processing.

Ovariectomy

Answer 8

For others who need a reliable time in Android, you can use this helpful library: https://github.com/homayoonahmadi/RealTime

Initialize it in Application class using time servers, NTP servers, or device location provider (GPS):

RealTime.builder(this)
     .withGpsProvider()
     .withNtpServer("time.google.com")
     .withNtpServer("time.windows.com")
     .withTimeServer("https://google.com")
     .withTimeServer(BuildConfig.API_BASE_URL)
     .setLoggingEnabled(BuildConfig.DEBUG)
     .setSyncBackoffDelay(5, TimeUnit.MINUTES)
     .build { date -> logd("RealTime initialized: $date") }

It needs to get current reliable time once until next device reboot. And you can get time like this:

if (RealTime.isInitialized()) {
    val reliableTime = RealTime.now()
}

Conyers

Answer 9

the time signal is not built into network antennas: you have to use the NTP protocol in order to retrieve the time on a ntp server. there are plenty of ntp clients, available as standalone executables or libraries.

the gps signal does indeed include a precise time signal, which is available with any "fix".

however, if nor the network, nor the gps are available, your only choice is to resort on the time of the phone... your best solution would be to use a system wide setting to synchronize automatically the phone time to the gps or ntp time, then always use the time of the phone.

note that the phone time, if synchronized regularly, should not differ much from the gps or ntp time. also note that forcing a user to synchronize its time may be intrusive, you 'd better ask your user if he accepts synchronizing. at last, are you sure you absolutely need a time that precise ?

Passbook

So, what is the "Automatic Date&Time" settings in my phone? "Use network-provided time" in every Android phone? – Gomes

Maybe "Automatic Date&Time" probably uses a NTP server itself? (I don't really know) – Buyers

This setting will call a google or provider NTP server and sync your time with this server. I found that the Motorola NTP server is off by two minutes ;) If you really need a very precise time make a network call to a trusted NTP server and use that time instead the phone time. – Sleepless

If Android uses NTP server, how can I update my time instantly after a cold boot with all data turned off except voice network? (I mean, all data turned off). I'd like to know. – Nadda

AFAIK, Android uses NITZ protocol (Network Identity and Time Zone - part of the GSM standard), for time sync over cell network and NOT the NTP one. Feature request for NTP support has not been implemented yet, though few users reported they were able to sync time over WiFi (possibly via NTP) on HoneyComb. However this information is not confirmed. – Oriane

I didn't know about NITZ. But from the code digging I have done, @Idolon is most likely to be right. – Morgan

This answer seems to be wrong, from the code I read. NTP is used somewhat in GPS localisation, though. – Morgan

@rds: this answer was, at first, only meant to clear some misconceptions in the questions. i don't know the specifics of Android, and i admit that i was not aware of NITZ (though, it is not supported everywhere). but one thing for sure: GPS does NOT use NTP ! the time signal, embedded in the GPS signal broadcast by all satellites, is very specific and is extremely accurate since it is the base of the localisation (GPS works by using a ephemeride+time system). – Passbook

@AdrienPlisson Yes, I know. And yet it moves. GpsLocationProvider requests pool.ntp.org (property NTP_SERVER) every 4 hours when network is available. This NTP time is injected in the GPS XTRA, in a native method. Strictly speaking, GPS does not need NTP. But in a real-world implementation where people don't want to wait, the GPS gets an extra hint with an approximative (NTP) time and approximative (GSM) location... – Morgan