Wrong klock DateTime conversion.

Overview (Required)

Several klock DateTime conversion code seems wrong…

Superficial problem.

The time when “Go to survey” is displayed is shifted.

1. Set Android device time like as 2019 Feb. 7, 21:00 (GMT+9:00 (Japan Standard Time))
2. launch droidkaigi app.

we expected following behavior. All Day1 Session is finished. (“Go to survey” is displayed).

but actual result is as follows. The session since lunch has not finished yet. (“Go to survey” is NOT displayed).

Code problem.

SessionDataMapperExt.kt

            stime = dateFormat.parse(startsAt).utc.unixMillisLong,
            etime = dateFormat.parse(endsAt).utc.unixMillisLong,

When endsAt is “2019-02-07T11:50:00”, etime indicate 2019 Feb 07 11:50:00 (GMT+0:00). But, the true meaning of “2019-02-07T11:50:00” in droidkaigi api response is 2019 Feb 07 11:50:00 (GMT+9:00).

Session.kt

    val isFinished: Boolean
        get() = DateTime.nowUnixLong() > endTime.unixMillisLong

When endsAt is “2019-02-07T11:50:00”, endTime indicate 2019 Feb 07 11:50:00 (GMT+0:00). This time same as 2019 Feb 07 20:50:00 (GMT+9:00 (Japan Standard Time)).

        append(startTime.format("hh:mm"))
        append(" - ")
        append(endTime.format("hh:mm"))

And more, “hh” means 12-hour notation. (see Session Detail screen) If we expect 24-hour notation, specify “HH”.

Appendix: Basic test code.

        val t1a: DateTimeTz =
            DateFormat("""yyyy-MM-dd'T'HH:mm:ss""").parse("2019-02-07T11:50:00")
        assertEquals(TimezoneOffset(0.0), t1a.offset)
        assertEquals(11, t1a.hours)
        assertEquals("11:50", t1a.format("HH:mm"))
        assertEquals(1549540200000, t1a.utc.unixMillisLong)

        val t1b: DateTime = t1a.utc
        assertEquals(11, t1b.hours)
        assertEquals("11:50", t1b.format("HH:mm"))

        val t1c: DateTimeTz = t1b.toOffset(TimezoneOffset((9*60*60*1000).toDouble()))
        assertEquals(TimezoneOffset((9*60*60*1000).toDouble()), t1c.offset)
        assertEquals(20, t1c.hours)
        assertEquals("08:50", t1c.format("hh:mm"))
        assertEquals("20:50", t1c.format("HH:mm"))
        assertEquals(t1a.utc.unixMillisLong, t1c.utc.unixMillisLong)

        val t2a: DateTimeTz =
            DateFormat("""yyyy-MM-dd'T'HH:mm:ssxxx""").parse("2019-02-07T11:50:00+09:00")
        assertEquals(TimezoneOffset((9*60*60*1000).toDouble()), t2a.offset)
        assertEquals(11, t2a.hours)
        assertEquals("11:50", t2a.format("HH:mm"))
        assertEquals(1549507800000, t2a.utc.unixMillisLong)

[jmatsu]

~I’ve added those TZ-aware fields to Session entities. Please check it out from https://droidkaigi2019-dev.appspot.com/api/timetable~

~Oops, sorry, was half asleep. I found a bug… let me address it.~

Fixed 🙇 I’ve added those TZ-aware fields to Session entities. Please check it out from https://droidkaigi2019-dev.appspot.com/api/timetable

[nukka123]

let me add the timezone information to the api.

nice! But, be careful. If api fix first, dateFormat.parse(startsAt) will be throws Exception. We need tempolary workaround like as

            stime = try {
                stime = dateFormat.parse(startsAt).utc.unixMillisLong
            } catch (e: Exception) {
                DateFormat.FORMAT1.parse(startsAt).utc.unixMillisLong
            }