add Android timezone offset support

README.md

@@ -52,7 +52,7 @@ React Native date & time picker component for iOS, Android and Windows.
     - [`value` (`required`)](#value-required)
     - [`maximumDate` (`optional`)](#maximumdate-optional)
     - [`minimumDate` (`optional`)](#minimumdate-optional)
-    - [`timeZoneOffsetInMinutes` (`optional`, `iOS only`)](#timezoneoffsetinminutes-optional-ios-only)
+    - [`timeZoneOffsetInMinutes` (`optional`, `iOS or Android only`)](#timezoneoffsetinminutes-optional-ios-only)
     - [`timeZoneOffsetInSeconds` (`optional`, `Windows only`)](#timezoneoffsetinsecond-optional-windows-only)
     - [`dayOfWeekFormat` (`optional`, `Windows only`)](#dayOfWeekFormat-optional-windows-only)
     - [`dateFormat` (`optional`, `Windows only`)](#dateFormat-optional-windows-only)
@@ -257,7 +257,7 @@ Defines the minimum date that can be selected. Note that on Android, this only w
 <RNDateTimePicker minimumDate={new Date(1950, 0, 1)} />
 ```
 
-#### `timeZoneOffsetInMinutes` (`optional`, `iOS only`)
+#### `timeZoneOffsetInMinutes` (`optional`, `iOS and Android only`)
 
 Allows changing of the timeZone of the date picker. By default it uses the device's time zone.
 

android/src/main/java/com/reactcommunity/rndatetimepicker/RNConstants.java

@@ -9,6 +9,7 @@ public final class RNConstants {
   public static final String ARG_IS24HOUR = "is24Hour";
   public static final String ARG_DISPLAY = "display";
   public static final String ARG_NEUTRAL_BUTTON_LABEL = "neutralButtonLabel";
+  public static final String ARG_TZOFFSET_MIN = "timeZoneOffsetInMinutes";
   public static final String ACTION_DATE_SET = "dateSetAction";
   public static final String ACTION_TIME_SET = "timeSetAction";
   public static final String ACTION_DISMISSED = "dismissedAction";

android/src/main/java/com/reactcommunity/rndatetimepicker/RNDate.java

@@ -1,13 +1,19 @@
 package com.reactcommunity.rndatetimepicker;
 
 import java.util.Calendar;
+import java.util.TimeZone;
 import android.os.Bundle;
 
 public class RNDate {
   private Calendar now;
 
   public RNDate(Bundle args) {
     now = Calendar.getInstance();
+    if (args != null && args.containsKey(RNConstants.ARG_TZOFFSET_MIN)) {
+      now.setTimeZone(TimeZone.getTimeZone("GMT"));
+      Integer timeZoneOffsetInMinutes = args.getInt(RNConstants.ARG_TZOFFSET_MIN);
+      now.add(Calendar.MILLISECOND, timeZoneOffsetInMinutes * 60000);
+    }
 
     if (args != null && args.containsKey(RNConstants.ARG_VALUE)) {
       set(args.getLong(RNConstants.ARG_VALUE));

android/src/main/java/com/reactcommunity/rndatetimepicker/RNTimePickerDialogModule.java

@@ -148,6 +148,9 @@ private Bundle createFragmentArguments(ReadableMap options) {
     if (options.hasKey(RNConstants.ARG_INTERVAL) && !options.isNull(RNConstants.ARG_INTERVAL)) {
       args.putInt(RNConstants.ARG_INTERVAL, options.getInt(RNConstants.ARG_INTERVAL));
     }
+    if (options.hasKey(RNConstants.ARG_TZOFFSET_MIN) && !options.isNull(RNConstants.ARG_TZOFFSET_MIN)) {
+      args.putInt(RNConstants.ARG_TZOFFSET_MIN, options.getInt(RNConstants.ARG_TZOFFSET_MIN));
+    }
     return args;
   }
 }

example/App.js

@@ -60,6 +60,7 @@ const MINUTE_INTERVALS = [1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30];
 
 export const App = () => {
   const [date, setDate] = useState(new Date(1598051730000));
+  const [tzOffsetInMinutes, setTzOffsetInMinutes] = useState(0);
   const [mode, setMode] = useState(MODE_VALUES[0]);
   const [show, setShow] = useState(false);
   const [color, setColor] = useState();
@@ -223,10 +224,20 @@ export const App = () => {
                 title="hide picker"
               />
             </View>
+            <View style={styles.button}>
+              <Button
+                testID="setTz"
+                onPress={() => {
+                  setTzOffsetInMinutes(60);
+                  setShow(true);
+                }}
+                title="setTz"
+              />
+            </View>
             {show && (
               <DateTimePicker
                 testID="dateTimePicker"
-                timeZoneOffsetInMinutes={0}
+                timeZoneOffsetInMinutes={tzOffsetInMinutes}
                 minuteInterval={interval}
                 value={date}
                 mode={mode}

example/e2e/detoxTest.spec.js

@@ -130,6 +130,34 @@ describe('Example', () => {
     }
   });
 
+  async function userOpensPickerTz({mode, display, interval}) {
+    await element(by.text(mode)).tap();
+    await element(by.text(display)).tap();
+    if (interval) {
+      await element(by.text(String(interval))).tap();
+    }
+    await element(by.id('setTz')).tap();
+  }
+
+  it('setTz should change time text when time changes 60 minutes', async () => {
+    await userOpensPickerTz({mode: 'time', display: 'default'});
+    const timeText = getTimeText();
+
+    if (isIOS()) {
+      const testElement = getDateTimePickerIOS();
+      await testElement.setColumnToValue(0, '2');
+      await testElement.setColumnToValue(1, '44');
+      await testElement.setColumnToValue(2, 'PM');
+
+      await expect(timeText).toHaveText('13:44');
+    } else {
+      await userChangesMinuteValue();
+      await userTapsOkButtonAndroid();
+
+      await expect(timeText).toHaveText('22:30');
+    }
+  });
+
   it(':android: given we specify neutralButtonLabel, tapping the corresponding button sets date to the beginning of the unix time epoch', async () => {
     await elementById('neutralButtonLabelTextInput').typeText('clear');
     await userOpensPicker({mode: 'time', display: 'default'});

src/constants.js

@@ -10,6 +10,7 @@ export const DISPLAY_DEFAULT = 'default';
 export const DISPLAY_SPINNER = 'spinner';
 export const DISPLAY_CLOCK = 'clock';
 export const DISPLAY_CALENDAR = 'calendar';
+export const MIN_MS = 60000;
 
 // TODO vonovak potentially replace the above string consts with this object
 export const ANDROID_DISPLAY = Object.freeze({

src/datetimepicker.android.js

@@ -12,6 +12,7 @@ import {
   NEUTRAL_BUTTON_ACTION,
   ANDROID_DISPLAY,
   ANDROID_MODE,
+  MIN_MS,
 } from './constants';
 import pickers from './picker';
 import invariant from 'invariant';
@@ -38,6 +39,7 @@ function getPicker({
   maximumDate,
   neutralButtonLabel,
   minuteInterval,
+  timeZoneOffsetInMinutes,
 }) {
   switch (mode) {
     case MODE_TIME:
@@ -47,6 +49,7 @@ function getPicker({
         minuteInterval,
         is24Hour,
         neutralButtonLabel,
+        timeZoneOffsetInMinutes,
       });
     case MODE_DATE:
     default:
@@ -72,6 +75,7 @@ export default function RNDateTimePicker(props: AndroidNativeProps) {
     maximumDate,
     neutralButtonLabel,
     minuteInterval,
+    timeZoneOffsetInMinutes,
   } = props;
   const valueTimestamp = value.getTime();
 
@@ -92,11 +96,12 @@ export default function RNDateTimePicker(props: AndroidNativeProps) {
         maximumDate,
         neutralButtonLabel,
         minuteInterval,
+        timeZoneOffsetInMinutes,
       });
 
       picker.then(
         function resolve({action, day, month, year, minute, hour}) {
-          const date = new Date(valueTimestamp);
+          let date = new Date(valueTimestamp);
           const event: AndroidEvent = {
             type: 'set',
             nativeEvent: {},
@@ -109,7 +114,14 @@ export default function RNDateTimePicker(props: AndroidNativeProps) {
               break;
 
             case TIME_SET_ACTION:
-              event.nativeEvent.timestamp = date.setHours(hour, minute);
+              date.setHours(hour, minute);
+              if (timeZoneOffsetInMinutes !== undefined) {
+                const offset =
+                  date.getTimezoneOffset() * MIN_MS +
+                  timeZoneOffsetInMinutes * MIN_MS;
+                date = new Date(date.getTime() - offset);
+              }
+              event.nativeEvent.timestamp = date;
               onChange(event, date);
               break;
 

src/types.js

@@ -136,6 +136,14 @@ export type AndroidNativeProps = $ReadOnly<{|
    */
   display: Display,
 
+  /**
+   * Timezone offset in minutes.
+   *
+   * By default, the date picker will use the device's timezone. With this
+   * parameter, it is possible to force a certain timezone offset. For
+   * instance, to show times in Pacific Standard Time, pass -7 * 60.
+   */
+  timeZoneOffsetInMinutes?: ?number,
   /**
    * The interval at which minutes can be selected.
    */