From af80d3fb9a3978281f24495e50bd9ec279b6d43a Mon Sep 17 00:00:00 2001
From: Sebastian Kranz <lightwars@web.de>
Date: Wed, 17 Jul 2019 14:19:37 +0200
Subject: [PATCH] NEW FEATURE: Add preference to turn your clock forward or
 backward, up to 10 minutes ahead or behind of your local time.

---
 .../activities/SettingsActivity.java          | 18 +++++++++++++
 .../casiogb6900/CasioGB6900DeviceSupport.java |  3 ++-
 .../service/devices/hplus/HPlusSupport.java   |  6 +++--
 .../service/devices/huami/HuamiSupport.java   |  3 ++-
 .../service/devices/id115/ID115Support.java   |  3 ++-
 .../devices/jyou/BFH16DeviceSupport.java      |  4 ++-
 .../devices/jyou/TeclastH30Support.java       |  4 ++-
 .../service/devices/miband/MiBandSupport.java |  2 +-
 .../service/devices/no1f1/No1F1Support.java   |  3 ++-
 .../devices/watch9/Watch9DeviceSupport.java   |  6 +++--
 .../service/devices/xwatch/XWatchSupport.java |  3 ++-
 .../devices/zetime/ZeTimeDeviceSupport.java   |  4 ++-
 .../gadgetbridge/util/DateTimeUtils.java      | 25 +++++++++++++++++++
 app/src/main/res/values/strings.xml           |  1 +
 app/src/main/res/xml/preferences.xml          |  6 +++++
 15 files changed, 78 insertions(+), 13 deletions(-)

diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/SettingsActivity.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/SettingsActivity.java
index 90cbcbfed..1ca79dbff 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/SettingsActivity.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/SettingsActivity.java
@@ -198,6 +198,24 @@ public class SettingsActivity extends AbstractSettingsActivity {
 
         });
 
+        pref = findPreference("datetime_turn_clocks_forward");
+        pref.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
+            @Override
+            public boolean onPreferenceChange(Preference preference, Object newVal) {
+                try {
+                    GBApplication.deviceService().onSetTime();
+                } catch (Exception ex) {
+                    GB.toast(getApplicationContext(),
+                            "Error setting new time: " + ex.getLocalizedMessage(),
+                            Toast.LENGTH_LONG,
+                            GB.ERROR,
+                            ex);
+                }
+                return true;
+            }
+
+        });
+
         final Preference unit = findPreference(PREF_MEASUREMENT_SYSTEM);
         unit.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
             @Override
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/casiogb6900/CasioGB6900DeviceSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/casiogb6900/CasioGB6900DeviceSupport.java
index d42233a0f..09a82d863 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/casiogb6900/CasioGB6900DeviceSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/casiogb6900/CasioGB6900DeviceSupport.java
@@ -54,6 +54,7 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.GattService;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.ServerTransactionBuilder;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.TransactionBuilder;
 import nodomain.freeyourgadget.gadgetbridge.service.devices.casiogb6900.operations.InitOperation;
+import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 import nodomain.freeyourgadget.gadgetbridge.util.StringUtils;
 
@@ -225,7 +226,7 @@ public class CasioGB6900DeviceSupport extends AbstractBTLEDeviceSupport {
 
     private void writeCasioCurrentTime(TransactionBuilder builder) {
         byte[] arr = new byte[10];
-        Calendar cal = Calendar.getInstance();
+        Calendar cal = DateTimeUtils.getCalendarTurnClockForward();
 
         int year = cal.get(Calendar.YEAR);
         arr[0] = (byte)((year >>> 0) & 0xff);
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/hplus/HPlusSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/hplus/HPlusSupport.java
index 2c0f43101..cc5042f3a 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/hplus/HPlusSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/hplus/HPlusSupport.java
@@ -59,6 +59,7 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.AbstractBTLEDeviceSuppo
 import nodomain.freeyourgadget.gadgetbridge.service.btle.TransactionBuilder;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.profiles.deviceinfo.DeviceInfo;
 import nodomain.freeyourgadget.gadgetbridge.util.AlarmUtils;
+import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 import nodomain.freeyourgadget.gadgetbridge.util.StringUtils;
 
@@ -191,7 +192,8 @@ public class HPlusSupport extends AbstractBTLEDeviceSupport {
     }
 
     private HPlusSupport setCurrentDate(TransactionBuilder transaction) {
-        Calendar c = GregorianCalendar.getInstance();
+        Calendar c = DateTimeUtils.getCalendarTurnClockForward();
+
         int year = c.get(Calendar.YEAR);
         int month = c.get(Calendar.MONTH);
         int day = c.get(Calendar.DAY_OF_MONTH);
@@ -208,7 +210,7 @@ public class HPlusSupport extends AbstractBTLEDeviceSupport {
     }
 
     private HPlusSupport setCurrentTime(TransactionBuilder transaction) {
-        Calendar c = GregorianCalendar.getInstance();
+        Calendar c = DateTimeUtils.getCalendarTurnClockForward();
 
         transaction.write(ctrlCharacteristic, new byte[]{
                 HPlusConstants.CMD_SET_TIME,
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/huami/HuamiSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/huami/HuamiSupport.java
index e7b7cd0a1..6b3384ed0 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/huami/HuamiSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/huami/HuamiSupport.java
@@ -120,6 +120,7 @@ import nodomain.freeyourgadget.gadgetbridge.service.devices.miband.NotificationS
 import nodomain.freeyourgadget.gadgetbridge.service.devices.miband.RealtimeSamplesSupport;
 import nodomain.freeyourgadget.gadgetbridge.service.serial.GBDeviceProtocol;
 import nodomain.freeyourgadget.gadgetbridge.util.AlarmUtils;
+import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.DeviceHelper;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 import nodomain.freeyourgadget.gadgetbridge.util.NotificationUtils;
@@ -256,7 +257,7 @@ public class HuamiSupport extends AbstractBTLEDeviceSupport {
     }
 
     public HuamiSupport setCurrentTimeWithService(TransactionBuilder builder) {
-        GregorianCalendar now = BLETypeConversions.createCalendar();
+        Calendar now = DateTimeUtils.getCalendarTurnClockForward();
         byte[] bytes = getTimeBytes(now, TimeUnit.SECONDS);
         builder.write(getCharacteristic(GattCharacteristic.UUID_CHARACTERISTIC_CURRENT_TIME), bytes);
         return this;
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/id115/ID115Support.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/id115/ID115Support.java
index 77363230d..33c33f760 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/id115/ID115Support.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/id115/ID115Support.java
@@ -45,6 +45,7 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.AbstractBTLEDeviceSuppo
 import nodomain.freeyourgadget.gadgetbridge.service.btle.GattService;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.TransactionBuilder;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.SetDeviceStateAction;
+import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 
 public class ID115Support extends AbstractBTLEDeviceSupport {
     private static final Logger LOG = LoggerFactory.getLogger(ID115Support.class);
@@ -269,7 +270,7 @@ public class ID115Support extends AbstractBTLEDeviceSupport {
     }
 
     ID115Support setTime(TransactionBuilder builder) {
-        Calendar c = Calendar.getInstance(TimeZone.getDefault());
+        Calendar c = DateTimeUtils.getCalendarTurnClockForward();
 
         int day = c.get(Calendar.DAY_OF_WEEK);
 
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/jyou/BFH16DeviceSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/jyou/BFH16DeviceSupport.java
index 923f99412..6d23b2df1 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/jyou/BFH16DeviceSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/jyou/BFH16DeviceSupport.java
@@ -81,6 +81,7 @@ import nodomain.freeyourgadget.gadgetbridge.model.WeatherSpec;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.AbstractBTLEDeviceSupport;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.TransactionBuilder;
 import nodomain.freeyourgadget.gadgetbridge.util.AlarmUtils;
+import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 import nodomain.freeyourgadget.gadgetbridge.util.StringUtils;
 
@@ -546,7 +547,8 @@ public class BFH16DeviceSupport extends AbstractBTLEDeviceSupport {
 
     //working
     private void syncDateAndTime(TransactionBuilder builder) {
-        Calendar cal = Calendar.getInstance();
+        Calendar cal = DateTimeUtils.getCalendarTurnClockForward();
+
         String strYear = String.valueOf(cal.get(Calendar.YEAR));
         byte year1 = (byte)Integer.parseInt(strYear.substring(0, 2));
         byte year2 = (byte)Integer.parseInt(strYear.substring(2, 4));
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/jyou/TeclastH30Support.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/jyou/TeclastH30Support.java
index 368966e15..ce299f145 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/jyou/TeclastH30Support.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/jyou/TeclastH30Support.java
@@ -47,6 +47,7 @@ import nodomain.freeyourgadget.gadgetbridge.model.WeatherSpec;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.AbstractBTLEDeviceSupport;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.TransactionBuilder;
 import nodomain.freeyourgadget.gadgetbridge.util.AlarmUtils;
+import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 import nodomain.freeyourgadget.gadgetbridge.util.StringUtils;
 
@@ -126,7 +127,8 @@ public class TeclastH30Support extends AbstractBTLEDeviceSupport {
     }
 
     private void syncDateAndTime(TransactionBuilder builder) {
-        Calendar cal = Calendar.getInstance();
+        Calendar cal = DateTimeUtils.getCalendarTurnClockForward();
+
         String strYear = String.valueOf(cal.get(Calendar.YEAR));
         byte year1 = (byte)Integer.parseInt(strYear.substring(0, 2));
         byte year2 = (byte)Integer.parseInt(strYear.substring(2, 4));
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java
index 72dcffb8d..baae9474d 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java
@@ -622,7 +622,7 @@ public class MiBandSupport extends AbstractBTLEDeviceSupport {
      * @param builder
      */
     private MiBandSupport setCurrentTime(TransactionBuilder builder) {
-        Calendar now = GregorianCalendar.getInstance();
+        Calendar now = DateTimeUtils.getCalendarTurnClockForward();
         Date date = now.getTime();
         LOG.info("Sending current time to Mi Band: " + DateTimeUtils.formatDate(date) + " (" + date.toGMTString() + ")");
         byte[] nowBytes = MiBandDateConverter.calendarToRawBytes(now, gbDevice.getAddress());
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/no1f1/No1F1Support.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/no1f1/No1F1Support.java
index 6639aa334..86837144e 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/no1f1/No1F1Support.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/no1f1/No1F1Support.java
@@ -59,6 +59,7 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.AbstractBTLEDeviceSuppo
 import nodomain.freeyourgadget.gadgetbridge.service.btle.TransactionBuilder;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.SetDeviceBusyAction;
 import nodomain.freeyourgadget.gadgetbridge.util.AlarmUtils;
+import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 
 import static org.apache.commons.lang3.math.NumberUtils.min;
@@ -395,7 +396,7 @@ public class No1F1Support extends AbstractBTLEDeviceSupport {
     }
 
     private void setTime(TransactionBuilder transaction) {
-        Calendar c = GregorianCalendar.getInstance();
+        Calendar c = DateTimeUtils.getCalendarTurnClockForward();
         byte[] datetimeBytes = new byte[]{
                 No1F1Constants.CMD_DATETIME,
                 (byte) ((c.get(Calendar.YEAR) / 256) & 0xff),
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/watch9/Watch9DeviceSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/watch9/Watch9DeviceSupport.java
index a99a07ad8..1eb5cb72c 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/watch9/Watch9DeviceSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/watch9/Watch9DeviceSupport.java
@@ -38,6 +38,7 @@ import java.util.UUID;
 
 import androidx.annotation.IntRange;
 import androidx.localbroadcastmanager.content.LocalBroadcastManager;
+
 import nodomain.freeyourgadget.gadgetbridge.deviceevents.GBDeviceEventBatteryInfo;
 import nodomain.freeyourgadget.gadgetbridge.deviceevents.GBDeviceEventVersionInfo;
 import nodomain.freeyourgadget.gadgetbridge.devices.watch9.Watch9Constants;
@@ -60,6 +61,7 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.SetDeviceStateA
 import nodomain.freeyourgadget.gadgetbridge.service.devices.watch9.operations.InitOperation;
 import nodomain.freeyourgadget.gadgetbridge.util.AlarmUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.ArrayUtils;
+import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 
 public class Watch9DeviceSupport extends AbstractBTLEDeviceSupport {
 
@@ -236,7 +238,7 @@ public class Watch9DeviceSupport extends AbstractBTLEDeviceSupport {
     }
 
     private void handleTime(byte[] time) {
-        GregorianCalendar now = BLETypeConversions.createCalendar();
+        Calendar now = DateTimeUtils.getCalendarTurnClockForward();
         GregorianCalendar nowDevice = BLETypeConversions.createCalendar();
         int year = (nowDevice.get(Calendar.YEAR) / 100) * 100 + Conversion.fromBcd8(time[8]);
         nowDevice.set(year,
@@ -250,7 +252,7 @@ public class Watch9DeviceSupport extends AbstractBTLEDeviceSupport {
         long timeDiff = (Math.abs(now.getTimeInMillis() - nowDevice.getTimeInMillis())) / 1000;
         if (10 < timeDiff && timeDiff < 120) {
             enableCalibration(true);
-            setTime(BLETypeConversions.createCalendar());
+            setTime(DateTimeUtils.getCalendarTurnClockForward());
             enableCalibration(false);
         }
     }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/xwatch/XWatchSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/xwatch/XWatchSupport.java
index c3bc3a04c..e1c74d8da 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/xwatch/XWatchSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/xwatch/XWatchSupport.java
@@ -59,6 +59,7 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.AbstractBTLEDeviceSuppo
 import nodomain.freeyourgadget.gadgetbridge.service.btle.TransactionBuilder;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.SetDeviceStateAction;
 import nodomain.freeyourgadget.gadgetbridge.service.devices.miband.DeviceInfo;
+import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 
 public class XWatchSupport extends AbstractBTLEDeviceSupport {
@@ -134,7 +135,7 @@ public class XWatchSupport extends AbstractBTLEDeviceSupport {
         LOG.debug("Sending current date to the XWatch");
         BluetoothGattCharacteristic deviceData = getCharacteristic(XWatchService.UUID_WRITE);
 
-        String time = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());
+        String time = new SimpleDateFormat("yyyyMMddHHmmss").format(DateTimeUtils.todayTurnClockForward());
         String y = time.substring(2, 4);
         String M = time.substring(4, 6);
         String d = time.substring(6, 8);
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/zetime/ZeTimeDeviceSupport.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/zetime/ZeTimeDeviceSupport.java
index ce493fb22..17cc52c0d 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/zetime/ZeTimeDeviceSupport.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/zetime/ZeTimeDeviceSupport.java
@@ -64,6 +64,7 @@ import nodomain.freeyourgadget.gadgetbridge.service.btle.GattService;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.TransactionBuilder;
 import nodomain.freeyourgadget.gadgetbridge.service.btle.actions.SetDeviceStateAction;
 import nodomain.freeyourgadget.gadgetbridge.util.AlarmUtils;
+import nodomain.freeyourgadget.gadgetbridge.util.DateTimeUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 import nodomain.freeyourgadget.gadgetbridge.util.Prefs;
 
@@ -1439,7 +1440,8 @@ public class ZeTimeDeviceSupport extends AbstractBTLEDeviceSupport {
 
     private void synchronizeTime(TransactionBuilder builder)
     {
-        Calendar now = GregorianCalendar.getInstance();
+        Calendar now = DateTimeUtils.getCalendarTurnClockForward();
+
         byte[] timeSync = new byte[]{ZeTimeConstants.CMD_PREAMBLE,
                 ZeTimeConstants.CMD_DATE_TIME,
                 ZeTimeConstants.CMD_SEND,
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/DateTimeUtils.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/DateTimeUtils.java
index c234a4a39..16a6fafd9 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/DateTimeUtils.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/DateTimeUtils.java
@@ -153,4 +153,29 @@ public class DateTimeUtils {
     public static String minutesToHHMM(int minutes) {
         return String.format(Locale.US, "%d:%02d", minutes / 60, minutes % 60); // no I do not want to use durationformatter :P
     }
+
+    public static Date todayTurnClockForward() {
+        Calendar now = getCalendarTurnClockForward();
+        return now.getTime();
+    }
+
+    public static Calendar getCalendarTurnClockForward() {
+        Calendar now = GregorianCalendar.getInstance();
+        // we will now check if the user likes to turn theirs clock forward or backward
+        // get the time entered on the preferences
+        int minutesToTurnClockForward = GBApplication.getPrefs().getInt("datetime_turn_clocks_forward", 0);
+        if(minutesToTurnClockForward > 10)
+        {   // check if the time is greater than 10 minutes forward; this could be changed to any value
+            minutesToTurnClockForward = 10;
+        } else if(minutesToTurnClockForward < -10)
+        {   // check if the time is greater than 10 minutes backward; this could be changed to any value
+            minutesToTurnClockForward = -10;
+        }
+        if(minutesToTurnClockForward != 0) { // if a value is given turn the actual clock time forwards or backwards
+            long timenow = now.getTimeInMillis(); // get the actual time in milli seconds
+            timenow += minutesToTurnClockForward * 60000; // convert the given minutes to milli seconds and add this to the actual time in milli seconds
+            now.setTimeInMillis(timenow); // set the "new time"
+        }
+        return now;
+    }
 }
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index b9adc3bc0..4383546aa 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -74,6 +74,7 @@
     <string name="pref_header_datetime">Date and Time</string>
     <string name="pref_title_datetime_syctimeonconnect">Sync time</string>
     <string name="pref_summary_datetime_syctimeonconnect">Sync time to Gadgetbridge device when connecting, and when time or time zone changes on Android device</string>
+    <string name="pref_title_datetime_turn_clocks_forward">Turn your clock forward</string>
     <string name="pref_title_theme">Theme</string>
     <string name="pref_theme_light">Light</string>
     <string name="pref_theme_dark">Dark</string>
diff --git a/app/src/main/res/xml/preferences.xml b/app/src/main/res/xml/preferences.xml
index 03f4e8552..1bd34d3b8 100644
--- a/app/src/main/res/xml/preferences.xml
+++ b/app/src/main/res/xml/preferences.xml
@@ -190,6 +190,12 @@
             android:key="datetime_synconconnect"
             android:summary="@string/pref_summary_datetime_syctimeonconnect"
             android:title="@string/pref_title_datetime_syctimeonconnect" />
+        <EditTextPreference
+            android:inputType="numberSigned"
+            android:key="datetime_turn_clocks_forward"
+            android:maxLength="2"
+            android:defaultValue="0"
+            android:title="@string/pref_title_datetime_turn_clocks_forward" />
     </PreferenceCategory>
     <PreferenceCategory
         android:key="pref_key_notifications"