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Set the NTP server of your android device
tags
Android
Android Things

Set the NTP server of your android device

Just use this command to set a server address to automatically sync your device time. ( ͡° ͜ʖ ͡°)✧

$ adb shell settings put global ntp_server <new-ntp-server>

Background

I have a Raspberry Pi 3 with Android Things installed on it. But the time is never synchronized...

After googling it, I found this piece of code in NtpTrustedTime.java

public class NtpTrustedTime implements TrustedTime {
    ...
    public static synchronized NtpTrustedTime getInstance(Context context) {
        if (sSingleton == null) {
            final Resources res = context.getResources();
            final ContentResolver resolver = context.getContentResolver();
            final String defaultServer = res.getString(
                    com.android.internal.R.string.config_ntpServer);
            final long defaultTimeout = res.getInteger(
                    com.android.internal.R.integer.config_ntpTimeout);
            final String secureServer = Settings.Global.getString(
                    resolver, Settings.Global.NTP_SERVER);
            final long timeout = Settings.Global.getLong(
                    resolver, Settings.Global.NTP_TIMEOUT, defaultTimeout);
            final String server = secureServer != null ? secureServer : defaultServer;
            sSingleton = new NtpTrustedTime(server, timeout);
            sContext = context;
        }
        return sSingleton;
    }
}

It shows that android tring to get NTP server from:

  1. Settings.Global.NTP_SERVER first

  2. Then com.android.internal.R.string.config_ntpServer

And the NTP server of my Android Things is time.android.com, that's why it dose not work (I'm in China...).


Fortunately, it is easy to set settings via adb:

$ adb shell settings put global ntp_server asia.pool.ntp.org

# test
$ adb shell settings get global ntp_server 
> asia.pool.ntp.org

🎉 CHEERS

@kylin17

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kylin17 commented May 18, 2018

How to sync device time from ntp server immediately?

@xujiaao

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xujiaao commented May 21, 2018

@kylin17

Sorry, I'm not familiar with that. If you are woking with Android Things, you can simply restart it...

@kylin17

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kylin17 commented May 23, 2018

@xujiaao
Ok, I will try. Thanks!

@chetstone

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chetstone commented Sep 6, 2018

Works for my android phone too! Thanks!

@mellsaid

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mellsaid commented Sep 13, 2018

Awesome!!! Few questions plz @xujiaao

  • Do we need to run this command every time we restart or power off the device?
  • Is there a way to permanently change the NTP server?
  • Also is there a way to add a list of servers like :

0.uk.pool.ntp.org
1.uk.pool.ntp.org
2.uk.pool.ntp.org
3.uk.pool.ntp.org

@xujiaao

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xujiaao commented Sep 26, 2018

Awesome!!! Few questions plz @xujiaao

  • Do we need to run this command every time we restart or power off the device?
  • Is there a way to permanently change the NTP server?
  • Also is there a way to add a list of servers like :

0.uk.pool.ntp.org
1.uk.pool.ntp.org
2.uk.pool.ntp.org
3.uk.pool.ntp.org

You do not need to run the command after restarting (Tested on my Android Phone)...

$ adb shell settings put global ntp_server asia.pool.ntp.org
$ adb shell settings get global ntp_server
> asia.pool.ntp.org

# restart the device
$ adb shell settings get global ntp_server
> asia.pool.ntp.org

But I do not think Android can support multiple NTP servers ... See the code above 😄

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