How to change color of divider in NSSplitView? - cocoa

Question

Can we change the color of the divider?
Apple documentations says, that we can override -dividerColor in subclass of NSSplitView for this, but it doesn't works for me, or my understanding isn't correct. Also I've try create color layer over divider, e.g.:
colorLayer = [CALayer layer];
NSRect dividerFrame = NSMakeRect([[self.subviews objectAtIndex:0] frame].size.width, [[self.subviews objectAtIndex:0] frame].origin.y, [self dividerThickness], self.frame.size.height);
[colorLayer setBackgroundColor:[color coreGraphicsColorWithAlfa:1]];
[colorLayer setFrame:NSRectToCGRect(dividerFrame)];
[self.layer addSublayer:colorLayer];
Not works.

Answer 1

This answer may be late but:
If you are using Interface Builder, it is possible to change the property by going to the Identity Inspector of the NSSplitView (cmd+alt+3) and adding a User Defined Runtime Attribute for dividerColor of the type Color.

Answer 2

Actually, simply subclassing NSSplitView and overriding -(void)dividerColor works, but works only for thin or thick divider.
I've created simple configurable split view like this:
#interface CustomSplitView : NSSplitView
#property NSColor* DividerColor
#end
#implementation CustomSplitView
- (NSColor*)dividerColor {
return (self.DividerColor == nil) ? [super dividerColor] : self.DividerColor;
}
#end
Then in Interface Builder specify custom class for your split view to be CustomSplitView and add new user defined runtime attribute with key path = DividerColor, type = Color and select desired splitter color.

Answer 3

I've tried subclassing - (void)dividerColor too and I'm not sure why it doesn't work even though I know it's being called (and it's in the documentation).
One way to change the color of the divider is to subclass - (void)drawDividerInRect:(NSRect)aRect. However, for some reason, this method isn't called and I've checked all over the web for answers, but couldn't find anything, so I ended up calling it from drawRect. Here is the code for the subclassed NSSplitView:
-(void) drawRect {
id topView = [[self subviews] objectAtIndex:0];
NSRect topViewFrameRect = [topView frame];
[self drawDividerInRect:NSMakeRect(topViewFrameRect.origin.x, topViewFrameRect.size.height, topViewFrameRect.size.width, [self dividerThickness] )];
}
-(void) drawDividerInRect:(NSRect)aRect {
[[NSColor redColor] set];
NSRectFill(aRect);
}

Answer 4

Based on Palle's answer, but with the possibility to change the color dynamically in code, I'm currently using this solution (Swift 4):
splitView.setValue(NSColor.red, forKey: "dividerColor")
If your splitview control is part of a NSSplitViewController, you should use something like this:
splitViewController?.splitView.setValue(NSColor.red, forKey: "dividerColor")

Answer 5

In Swift and on macOS 11 I was able to achieve this by simply subclassing the NSSPlitView and only override drawDivider()
import Foundation
import AppKit
class MainSplitView: NSSplitView {
override func drawDivider(in rect: NSRect) {
NSColor(named: "separatorLinesColor")?.setFill()
rect.fill()
}
}
I had previously tried some of the other way, listed in here and what used to work stopped working with macOS 11... but it seems that this works.

Answer 6

One important point I haven't seen mentioned anywhere is that if you are overriding drawRect in a split view then you must call super -- otherwise drawDividerInRect: is never called. So, it should go something like this:
- (void)drawRect:(NSRect)dirtyRect {
// your other custom drawing
// call super last to draw the divider on top
[super drawRect:dirtyRect];
}
- (void)drawDividerInRect:(NSRect)aRect {
[[NSColor blueColor] set];
NSRectFill(aRect);
}