I was looking for examples of how to set an NSTableView row’s background color based on a value in the row. I didn’t find anything but came up with a method I thought I’d share. I subclassed NSTableView and overrode drawBackgroundInClipRect:. It gets the background color from the delegate through a call to tableView:backgroundColorForRow:. To leave the background color at the default, the delegate simply returns nil.

Here’s the header (including a protocol that the delegate can conform to):

@interface RowColorTableView : NSTableView { BOOL delegateRespondsToBackgroundColorForRow; }

@end

@protocol RowColorTableViewDelegate

• (NSColor *)tableView:(RowColorTableView *)aTableView backgroundColorForRow:(NSInteger)rowIndex; @end

and the implementation:

#import “RowColorTableView.h”

@implementation RowColorTableView

• (void)awakeFromNib { delegateRespondsToBackgroundColorForRow = self delegate] respondsToSelector:@selector(tableView:backgroundColorForRow:)]; }

• (void)drawBackgroundInClipRect:([[NSRect)clipRect { //First draw default background [super drawBackgroundInClipRect:clipRect];

  if (delegateRespondsToBackgroundColorForRow) { //Now draw custom background where necessary NSRange rowRange = [self rowsInRect:clipRect]; for (int rowIndex=rowRange.location; rowIndex<rowRange.location + rowRange.length; rowIndex++) { NSColor *bgndColor = self delegate] tableView:self backgroundColorForRow:rowIndex]; if (bgndColor) { [bgndColor set]; [[[NSBezierPath fillRect:[self rectOfRow:rowIndex]]; } } } }

@end

-SteveNicholson