+6  A: 

The simplest way is probably to subclass NSTextFieldCell and override -drawInteriorWithFrame:inView: and -selectWithFrame:inView:editor:delegate:start:length:.

You'll need to decide how much space to allocate for your count and draw in the abbreviated space. Something like this example code should work although this hasn't been tested in a rounded text field.

You can find more information about subclassing NSCell in Apple's PhotoSearch example code.

- (void)drawInteriorWithFrame:(NSRect)bounds inView:(NSView *)controlView {
    NSRect titleRect = [self titleRectForBounds:bounds];
    NSRect countRect = [self countAreaRectForBounds:bounds];

    titleRect = NSInsetRect(titleRect, 2, 0);

    NSAttributedString *title = [self attributedStringValue];
    NSAttributedString *count = [self countAttributedString];

    if (title)
        [title drawInRect:titleRect];

    [count drawInRect:countRect];
}

- (void)selectWithFrame:(NSRect)aRect inView:(NSView *)controlView editor:(NSText *)textObj delegate:(id)anObject start:(NSInteger)selStart length:(NSInteger)selLength {
    NSRect selectFrame = aRect;
    NSRect countRect = [self countAreaRectForBounds:aRect];

    selectFrame.size.width -= countRect.size.width + PADDING_AROUND_COUNT;

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(__textChanged:) name:NSTextDidChangeNotification object:textObj];
    [super selectWithFrame:selectFrame inView:controlView editor:textObj delegate:anObject start:selStart length:selLength];
}

- (void)endEditing:(NSText *)editor {
    [[NSNotificationCenter defaultCenter] removeObserver:self name:NSTextDidChangeNotification object:editor];

    [super endEditing:editor];
}

- (void)__textChanged:(NSNotification *)notif {
    [[self controlView] setNeedsDisplay:YES];
}
Ashley Clark
Thanks for the help, I'll try that.
Jeena