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

User · Answer

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 ?

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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

User · Answer

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   lt uses-permission android name  android permission WRITE SETTINGS   gt

User · Answer

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

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

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