Bug 288164

Description tnmdeuce@yahoo.com 2009-08-31 13:40:49 EDT

User-Agent:       Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; GTB5; .NET CLR 1.1.4322; .NET CLR 2.0.50727; yie8)
Build Identifier: M20090211-1700

If the selected date has the day 29, 30, or 31, the month selector in the drop down displays two Marchs instead of Feb. Mar.

Reproducible: Always

Steps to Reproduce:
1.Create a date control with DROP_DOWN option.
2.Set the selected date to Aug. 31 of any year.
3.Push the month button in the header.
4.Observe the two Marchs in the selector.



This problem occurs becase the DatePicker class is using the selected date to determine the month.  This is done by setting the month field in the calender instance for each button to the months ordinal value (0-11).  If the selected Calendar.DATE is > 28, Feb is incorrectly calculated as Mar.

This methodology also has other implications.  If the selected date is the 31st of, say, August, and June is selected from the month selector, July 1st becomes the selected date, since June has only 30 days.  It would seem the selected date should be June 30th.  If Feb is selected, the date should be Feb 28th (or 29th).

I've worked around this issue by setting the date field to 1 in the temporary calendar instances used for determining the month and selecting the maximum allowed date value for a chosen month when the selected date(dat) exceeds that value.

These are the changes I've made...

in DatePicker.createHeader switch case MONTH:

for(int i = 0; i < 12; i++) {
        Calendar tmpcal = cdt.getCalendarInstance();
	tmpcal.set(Calendar.DATE, 1);   // <===  Added this
	tmpcal.set(Calendar.MONTH, i);
	monthItems[i] = new MenuItem(monthMenu, SWT.NONE);
	monthItems[i].setData("Month", new Integer(tmpcal.get(Calendar.MONTH)));


in DatePicker.createMonths(Body b)...

Calendar tmpcal = cdt.getCalendarInstance();

// Added from here...
Calendar selected = cdt.getCalendarInstance();
selected.set(Calendar.DATE, 1);
selected.set(Calendar.MONTH, (Integer) button.getData("Month")); //$NON-NLS-1$
if (selected.getActualMaximum(Calendar.DATE) < tmpcal.get(Calendar.DATE)) {
	tmpcal.set(Calendar.DATE, selected.getActualMaximum(Calendar.DATE));
}
// ... to here

tmpcal.set(Calendar.MONTH, (Integer) button.getData("Month")); //$NON-NLS-1$
cdt.setSelection(tmpcal.getTime());

in DatePicker.updateHeader...

Calendar tmpcal = cdt.getCalendarInstance();
for(int i = 0; i < 12; i++) {
	tmpcal.set(Calendar.DATE, 1);    // <==  added this line
	tmpcal.set(Calendar.MONTH, i);

in

Calendar tmpcal = cdt.getCalendarInstance();
for(int i = 0; i < 12; i++) {
    tmpcal.set(Calendar.DATE, 1);    // <== added this line
    tmpcal.set(Calendar.MONTH, i);