Android - Check if current time is between 2 given times and the day of the week is valid

Question

I have to take an action if the time falls between start and stop time and on a specific day. I referred some existing threads on SO to check if the time falls within the specified time range.

Say if start time is 23:00pm, stop time is 7:00am and current time is 2:00am. Just the time validity function returns true. But if I include days in this code, the function returns false. Eg: user selects [Monday, Tuesday, Wednesday]. Even though Thursday is not in the list, but the end time 7:00am falls on Thursday, action can be taken anytime between 23:00pm Wed - 7:00am Thu, but action cannot be taken on 23:00pm Thu or any days not mentioned in the list.

Below is my code:

private fun isCurrentTimeBetweenProvidedTime(context: Context): Boolean {
        var reg = "^([0-1][0-9]|2[0-3]):([0-5][0-9]):([0-5][0-9])$".toRegex()
        val startTime = getStartTime()
        val endTime = getEndTime()
        val currentTime = getCurrentTime()

        if (reg.containsMatchIn(startTime) && reg.containsMatchIn(endTime) && reg.containsMatchIn(currentTime)) {
            var valid = false

            var startTime = SimpleDateFormat("HH:mm:ss").parse(startTime)
            var startCalendar = Calendar.getInstance()
            startCalendar.time = startTime

            var currentTime = SimpleDateFormat("HH:mm:ss").parse(currentTime)
            var currentCalendar = Calendar.getInstance()
            currentCalendar.time = currentTime

            var endTime = SimpleDateFormat("HH:mm:ss").parse(endTime)
            var endCalendar = Calendar.getInstance()
            endCalendar.time = endTime

            if (currentTime.compareTo(endTime) < 0) {
                currentCalendar.add(Calendar.DATE, 1)
                currentTime = currentCalendar.time
            }

            if (startTime.compareTo(endTime) < 0) {
                startCalendar.add(Calendar.DATE, 1)
                startTime = startCalendar.time
            }

            if (currentTime.before(startTime)) {
                valid = false
            } else {
                if (currentTime.after(endTime)) {
                    endCalendar.add(Calendar.DATE, 1)
                    endTime = endCalendar.time
                }

                if (currentTime.before(endTime)) {
                    valid = true
                } else {
                    valid = false
                }
            }

            // This won't work if day is Thursday and time is 2:00am, even though time falls between 23:00-7:00
            var todayCalendar = Calendar.getInstance()
            if ((currentTime >= startTime && todayCalendar.get(Calendar.DAY_OF_WEEK) in selectedDays.values) &&
                    (currentTime <= endTime && (todayCalendar.get(Calendar.DAY_OF_WEEK) in selectedDays.values || todayCalendar.get(Calendar.DAY_OF_WEEK)-1 in selectedDays.values))) {
                Log.d(TAG, "Days are valid")
            }

            return valid
        }

        return false
    }

How do I handle the days scenario?

Answer 1

java.time and ThreeTenABP

Please note: This code can work on Android API levels both under and over level 26. I will explain further down. I will have to trust you to translate from Java code.

If I have understood your requirements correctly:

    ZoneId zone = ZoneId.of("America/Chihuahua");

    LocalTime startTime = LocalTime.of(23, 0);
    LocalTime endTime = LocalTime.of(7, 0);
    Set<DayOfWeek> selectedDays
            = EnumSet.of(DayOfWeek.MONDAY, DayOfWeek.TUESDAY, DayOfWeek.WEDNESDAY);

    ZonedDateTime now = ZonedDateTime.now(zone);
    LocalTime timeNow = now.toLocalTime();
    DayOfWeek currentDayOfWeek = now.getDayOfWeek();
    boolean inIntervalOnDay;
    if (startTime.isAfter(endTime)) { // crosses midnight
        if (timeNow.isBefore(endTime)) { // in interval, after midnight
            // Day is correct if the day before is among the selected days
            inIntervalOnDay = selectedDays.contains(currentDayOfWeek.minus(1));
        } else if (timeNow.isBefore(startTime)) {
            inIntervalOnDay = false;
        } else { // after start time, before midnight
            inIntervalOnDay = selectedDays.contains(currentDayOfWeek);
        }
    } else {
        inIntervalOnDay = ! timeNow.isBefore(startTime)
                && timeNow.isBefore(endTime)
                && selectedDays.contains(currentDayOfWeek);
    }
    System.out.println("Now: " + now + " (" + currentDayOfWeek + ") Valid? " + inIntervalOnDay);

When I ran the snippet just now, the output was:

Now: 2019-09-27T03:47:56.856-06:00[America/Chihuahua] (FRIDAY) Valid? false

Please substitute your desired time zone if it didn’t happen to be America/Chihuahua. Time zone matters.

Question: Can I use java.time on Android below API level 26? How?

Yes, java.time works nicely on older and newer Android devices. It just requires at least Java 6.

• In Java 8 and later and on newer Android devices (from API level 26) the modern API comes built-in.
• In Java 6 and 7 get the ThreeTen Backport, the backport of the modern classes (ThreeTen for JSR 310; see the links at the bottom).
• On (older) Android use the Android edition of ThreeTen Backport. It’s called ThreeTenABP. And make sure you import the date and time classes from org.threeten.bp with subpackages.

Links

• Oracle tutorial: Date Time explaining how to use java.time.
• Java Specification Request (JSR) 310, where java.time was first described.
• ThreeTen Backport project, the backport of java.time to Java 6 and 7 (ThreeTen for JSR-310).
• ThreeTenABP, Android edition of ThreeTen Backport
• Question: How to use ThreeTenABP in Android Project, with a very thorough explanation.

Answer 2

One possible approach could be to normalize all your times to offsets from a chosen week starting point, say Sunday 12:00am = 0. Convert all your times into minutes since the starting point. Then simply check whether your chosen time (also converted to minutes since start) falls within any of the ranges.