NSView wont use CALayer at all - cocoa

Question

I've tried everything and read a LOT about using a CALayer in a NSView, but can't get code that worked fine on iOS to work on a Mac.
I'm calling
[ nsView setLayer:[CALayer layer]];
[ nsView wantsLayer];
to create a layer as I've read everywhere I should.
then I've tried settings the layer's background color, and adding a sublayer and setting it's background color, but I just get a black window no matter what I do.
The entire programatically created app is, after removing all nibs etc, trying to make a gradient to be sure I get some Layer content:
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
NSWindow *mainWindow;
NSView *nsView;
mainWindow = [[NSWindow alloc] initWithContentRect:NSMakeRect(20, 500, 200, 400)//screenRect
styleMask:NSTitledWindowMask
backing:NSBackingStoreBuffered
defer:NO];
[mainWindow setTitle:#"My Window"];
CAGradientLayer *layer;
nsView = [ [ NSView alloc] initWithFrame:NSMakeRect(20, 20, 200, 400)];
[mainWindow makeKeyAndOrderFront:nil];
[ nsView setLayer:[CALayer layer]];
[ nsView wantsLayer];
[ nsView setLayerContentsRedrawPolicy:NSViewLayerContentsRedrawOnSetNeedsDisplay];
layer = [CAGradientLayer layer];
layer.frame = CGRectMake(0, 0, 200, 400);
layer.colors = #[ (id)CGColorCreateGenericRGB(1, 0, 0, 1), (id)CGColorCreateGenericRGB(1, 1, 0, 1) ];
layer.startPoint = CGPointMake(0.5, 0);
layer.endPoint = CGPointMake(0.5, 1);
[nsView.layer addSublayer:layer];
[layer setNeedsDisplay];
[nsView setNeedsDisplay:YES];
[mainWindow setContentView:nsView];
}
no matter what I do, I never get any indication that the layer is being used. It and subviews exists when I debug, but are never shown. The view's drawRect method is called once as well.
I've read for days about using CALayers for NSViews, but nothing seems to get them working.
Any suggestions?

Answer 1

It was something amazingly simple but easy to be blind about:
I was calling:
[nsView wantsLayer]
(thinking it was a way of setting wantsLayer (probably infuenced by seeing it as a property)).
Which is just a getter that was being ignored.
[nsView setWantsLayer:YES]
or
nsView.wantsLayer = YES;
would of course be what I wanted.