NSTableView notification when column resizing has finished?

Question

With an NSTableview I can subscribe to the NSTableViewColumnDidResizeNotification to get events of a column being resized:

[[NSNotificationCenter defaultCenter] addObserver: self
                                         selector: @selector(tableColumnsResized)
                                             name: NSTableViewColumnDidResizeNotification
                                           object: dataTableView];

However, I'm looking to only get a notification once the resizing has finished (so that I can save some details). If I run the code every notification, then the column resizing stutters a bit. This is why I would like to only be notified when the resizing has finished.

Any suggestions how how I could do this?

Answer 1

You should set a short timer whenever you receive the resize notification, cancelling any previous timer. You can then perform your final action in the timer fired method:

.h:

@interface MyClass : NSView
{
    NSTimer *_columnResizeTimer;
}

@end

.m:

// Private Methods
@implementation MyClass ()

- (void)_columnResized:(NSTimer *)timer;

@end

@implementation MyClass

- (void)dealloc
{
    [_columnResizeTimer invalidate];
    _columnResizeTimer = nil;

    // If using MRR:
    [super dealloc];
}

- (void)tableViewColumnDidResize:(NSNotification *)notification
{
    [_columnResizeTimer invalidate];
    _columnResizeTimer = [NSTimer scheduledTimerWithTimeInterval:0.5
                                                          target:self
                                                        selector:@selector(_columnResized:)
                                                        userInfo:nil
                                                         repeats:NO];
}

- (void)_columnResized:(NSTimer *)timer
{
    [_columnResizeTimer invalidate];
    _columnResizeTimer = nil;

    // Do stuff on column resize
}

@end

(This code is untested and possibly buggy).