onMonthScroll scrolling fast damages the year of the parameter firstDayOfMonth

[sundeepk]

onMonthScroll scrolling fast damages the year of the parameter firstDayOfMonth

[SundeepK]

Are you on the latest version? I have tried to reproduce this, but I'm finding it difficult to do so. Are you using the sample or have you modified any thing?

[carlastabile]

@SundeepK I'm using version 1.7.9. I know its hard to reproduce it and it doesn't happen all the time. It is really really weird you need to scroll like 12 months away to start seeing it.

[SundeepK]

I have scrolled years and haven't spotted it, you are using the sample project correct?

[carlastabile]

@SundeepK this is my code:

 calendarView.setListener(new CompactCalendarView.CompactCalendarViewListener() {
        @Override
        public void onDayClick(Date dateClicked) {
            currentSelectedDate = dateClicked;
            dateSelected.setText(DateUtil.getCalendarShowableDate(dateClicked));
        }

        @Override
        public void onMonthScroll(Date firstDayOfNewMonth) {
            setMonthName(dateFormatForMonth.format(firstDayOfNewMonth)); //here I'm showing month and year in the Toolbar

            Calendar scrolledCalendar = Calendar.getInstance();
            scrolledCalendar.setTime(firstDayOfNewMonth);

            todayCal = Calendar.getInstance(Locale.getDefault());

            //If I scrolled to the current month, set the day to the current day
            if (todayCal.get(Calendar.MONTH) == scrolledCalendar.get(Calendar.MONTH) &&
                    todayCal.get(Calendar.YEAR) == scrolledCalendar.get(Calendar.YEAR)) {
                scrolledCalendar.set(Calendar.DAY_OF_MONTH, CalendarContainer.this.todayCal.get(Calendar.DAY_OF_MONTH));
                calendarView.setCurrentDate(scrolledCalendar.getTime());
            }
            dateSelected.setText(DateUtil.getCalendarShowableDate(scrolledCalendar.getTime()));
            presenter.getEventsByStartDate(scrolledCalendar.getTime());
        }
    });

[SundeepK]

I suspect a bug on setting the current date using setCurrentDate() whilst in the callback.

[carlastabile]

@SundeepK Do you mean I can't call setcurrentDate inside the onMonthScroll? Sorry, I didn't understand that last comment.

[SundeepK]

Well it might be a bug in the library when setting the current day whilst in the callback. Under the hood, it uses java Calendar object, which is not the nicest class you work with and is mutable. Might be some inconsistency while setting the date which could be causing the problem, but I will investigate.

I have copied your code directly and I can see the bug as you describe.

[SundeepK]

Ok I think I found the problem, under the hood, the library uses OverScroller to keep track of how far the user has scrolled in x direction. When setting the date, the current date was being initialized correctly with the one passed in but the OverScroller current x direction was not being reset to 0.

This causes a problem since internally it uses OverScroller is used to keep track how many months user has scrolled in +/- and sets the date accordingly.

I think solution is simple as calling scroller.startScroll(0,0,0,0); when setting the date. Also would be a good place to reset any internal values to 0 just to be sure.

[SundeepK]

This also leads to anther method to be exposed by the library which is scrollBackToCurrentDate(). This will allow user to easily scroll back to the currently set date in the calendar through scroller.startScroll((int) accumulatedScrollOffset.x,0, (int) - accumulatedScrollOffset.x,0); and will play an animation. But this is totally out of scope of this issue.

[SundeepK]

After a bit of playing around, I've taken the pragmatic approach by simply calling scroller.startScroll(0,0,0,0); to fix the bug. However, this doesn't have the nicest effect since it makes the calender reset its X position to 0 with a really quick scrolling animation . Unfortunately, the ``OverScroller` class provided in the Android SDK doesn't allow you to simply set an X value without scroll, which is annoying.

I will have another look at refining this, but I much rather fix the problem than have it perfect.

[SundeepK]

Changes are in master, will be released in the next day.

[SundeepK]

Re-opening until I actually release a new version so other people can see the issue.

[SundeepK]

Available in version:

dependencies {
    compile 'com.github.sundeepk:compact-calendar-view:1.8.0'
}