Header of Sortable CellTable Column not Responsive - gwt

Question

I am using GWT 2.5 to create a CellTable with a sortable date column.
My code is as follows:
CellTable<Activity> table = new CellTable<Activity>();
table.setRowStyles(new RowStyles<Activity>() {
#Override
public String getStyleNames(Activity row, int rowIndex) {
return TABLE_ROW_STYLE_NAME;
}
});
// create date column
TextColumn<Activity> dateColumn = new TextColumn<Activity>() {
#Override
public String getValue(Activity a) {
return dateFormat.format(a.getDate());
}
};
dateColumn.setSortable(true);
dateColumn.setDefaultSortAscending(false);
// add column to table
table.addColumn(dateColumn, myConstants.dateColumnHeader());
// attach provider to table
activityProvider.addDataDisplay(table);
// create sort handler
ListHandler<Activity> sortHandler = new ListHandler<Activity>(activityProvider.getList());
sortHandler.setComparator(dateColumn, new Comparator<Activity>() {
#Override
public int compare(Activity a1, Activity a2) {
if (a1 == a2) {
return 0;
}
// compare the date columns
if (a1 != null) {
if (a2 != null) {
long a1Val = a1.getDate().getTime();
long a2Val = a2.getDate().getTime();
if (a1Val == a2Val) {
return 0;
}
else if (a1Val > a2Val) {
return 1;
}
else {
return -1;
}
}
else {
return 1;
}
}
return -1;
}
});
// add sort handler to table
table.addColumnSortHandler(sortHandler);
// add date column to table's sort list
table.getColumnSortList().push(dateColumn);
table.setWidth("100%");
getView().getActivityPanel().add(table);
With this code, the data is displayed in the table and the sorting arrow on the column appears. However, nothing happens when I click on the sortable column's header. The sorting order doesn't change, rows are not rearranged.
Can anyone spot the problem here? This code is almost the same as what they have in Google's own example.

Answer 1

This is what I use:
dateColumn.setSortable(true);
sortHandler.setComparator(dateColumn, new Comparator<ObjectPobject>() {
public int compare(ObjectPobject o1, ObjectPobject o2) {
return o1.getDate().compareTo(o2.getDate());
}
});

Answer 2

It should be
a1.getDate().getTime().compareTo(a2.getDate().getTime())
or
a1.getDate().after(a2.getDate())
This happens because GWT uses JavaScript comparisons, and compareTo does not work for dates.