I have an NSTableView which shows the longitude and latitude points of objects on a map. Some objects, like trails, have many rows in the table. When I change objects I want to update the NSTableView and then select row 0. I tried
[obectCoordTable reloadData];
[objectCoordTable selectRowIndexes: [NSIndexSet indexSetWithIndex: 0] byExtendingSelection: NO];
This does not work because reloadData does not reload the table. It only schedules a reload for some time later
(on next iteration of Main Loop?). So my attempt to select row 0 happens first. Then just before the table
data are reloaded a (void)tableViewSelectionDidChange: happens with selected row reset to -1. So my
selection of row 0 is ineffective.
How do I select row 0 after the reload is finished? There seems to be no delegate method to notify the user
when a complete data reload is completed.
Do I have to schedule the selectRowIndexes for execution at a later time and hope it is after the data reload? That might work but seems a bit too hokey?
Thanks.
Richard Stover
Unfortunately NSTableView does not respond to layoutIfNeeded. But your suggestion led me into looking
at other possibilities.
Instead of doing the selectRowIndexes: after the reloadData I set a BOOL flag, needsReselect.
Then in the delegate tableView:objectValueForTableColumn:row: method I put this code:
// If we are updating the table content at row 0 and we need to reset the selection to row 0
// then do that now.
if ((rowIndex == 0) && needsReselect) {
// Select row 0.
[objectCoordTable selectRowIndexes: [NSIndexSet indexSetWithIndex: 0] byExtendingSelection: NO];
// Get the rectangle for the table contents.
CGRect r = objectCoordTable.superview.layer.contentsRect;
// Narrow the rect to an area that is part of row 0.
NSRect row0 = NSMakeRect(0.0, r.size.height - 10.0, r.size.width, 5.0);
// Scroll to that rect
[objectCoordTable.superview scrollRectToVisible:row0];
needsReselect = NO;
}This seems a little more obvious that using a dispatch queue and it seems to work. Note that I had to explicitly reset
the scroll as well. I checked, and if I'm not in the middle of the tableView:objectValueForTableColumn: the scoll
adjusts without need to control it explicitly.
It would be nice if there was a delegate method to mark the end of a reloadData, or an NSNotification about it.
Thanks for the help.
