codenameone - com.codename1.ui.Calendar Component DST Issue Causing Incorrect Day Selection - Stack Overflow

admin管理员组

文章数量:1391951

Dear Codename One Team,

I have encountered an issue in the Codename One com.codename1.ui.Calendar component that affects day selection when Daylight Savings Time (DST) changes within the month.

Issue Description:

The setCurrentDay method's current implementation increments days using startDate += 86400000L; (adding a fixed 24-hour period). When the DST transition occurs, the system adjusts the time forward (e.g., from 1 AM to 3 AM), causing the selected days to shift from 1 AM to 2 AM. As a result, this causes incorrect date selection behavior when comparing:

• startDate (which now has an unexpected hour shift) with SELECTED_DAY
• selectedDays.contains(new Date(dates[j])), since dates[j] may have been shifted by an hour.

Proposed Fix:

Instead of adding 86400000L manually, use Calendar.add(), which correctly handles DST transitions:

 for (; j < components.length && (j - i + 1) <= lastDay; j++) {
                setDayEnabled(components[j], true);
                dates[j] = startDate;
                if (dates[j] == SELECTED_DAY) {
                    setDayUIID(components[j], "CalendarSelectedDay");
                    selected = components[j];
                } else {
                    setDayUIID(components[j], "CalendarDay");
                }

                for (Map.Entry<String, Collection<Date>> entry : highlightGroup.entrySet()) {
                    if (entry.getValue().contains(new Date(dates[j]))) {
                        setDayUIID(components[j], entry.getKey());
                    }
                }

                if (multipleSelectionEnabled) {
                    if (selectedDays.contains(new Date(dates[j]))) {
                        setDayUIID(components[j], selectedDaysUIID);
                    }
                }
                updateButtonDayDate(components[j], yearNew, month, j - i + 1);
                //startDate += DAY; // Current Implementation 

                // Fixed Code
                cal.setTime(new Date(startDate));
                cal.add(java.util.Calendar.DAY_OF_MONTH, 1);
                startDate = cal.getTime().getTime();
                // End Code Fided
            }

This ensures that date calculations respect DST changes without shifting the hour.

I hope this helps improve Codename One’s Calendar component. Please let me know if you need further details.

Best regards, Oscar Naranjo

本文标签： codenameonecomcodename1uiCalendar Component DST Issue Causing Incorrect Day SelectionStack Overflow