Re: Problem with CALayer delegate

FROM : Matt Long
DATE : Sat Feb 23 06:20:50 2008

You could try creating your own CALayer derived class that overrides

- (void)drawInContext:(CGContextRef)ctx

drawLayer simply allows your delegate to override that same method 
externally.

-Matt


On Feb 22, 2008, at 9:52 PM, Francois-Jean De Brienne wrote:

> Hello everyone,
>
> I'm a very new cocoa developer (I switched two months ago) but an 
> experienced (15+ years) developer.
>
> I'm struggling trying to get a CALayer delegate method, specifically 
> drawLayer being called. I am trying to host the CALayer inside an 
> NSView that would be the delegate for the CALayer.
>
> The CALayer is an attribute of my custom NSView called mainLayer.
>
> Here is the initWithFrame method for my custom NSView:
>
> -(id) initWithFrame: (NSRect) frameRect
> {
>     self = [super initWithFrame:frameRect];
>     
>     if (self)
>     {
>         mainLayer = [[[CALayer alloc] init] retain];
>         
>         [mainLayer setDelegate:self];
>         [self setLayer:mainLayer];
>         [self setWantsLayer:YES];
>     }
>     
>     return self;
> }
>
> Then, the custom NSView declares a drawLayer method as such (that 
> I'd want to be called from my mainLayer):
>
> -(void)drawLayer:(CALayer*) layer inContext:(CGContextRef)ctx
> {
>     NSLog (@"Entered drawLayer");
> }
>
> Now, whenever I send the setNeedsDisplay message to mainLayer, I 
> assume that drawLayer would be called. It is not.
>
> drawLayer is also declared in the .h for the custom NSView (if that 
> makes any difference).
>
> If I override and define drawRect for my NSView, I can verify that 
> it does enter that method:
>
> - (void)drawRect:(NSRect)rect
> {
>     NSLog (@"Entered drawRect");
> }
>
>
> What am I doing wrong?
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