Custom NSButtonCell, drawBezelWithFrame not called - macos

Question

I'm trying to figure out how to custom draw Buttons in Cocoa/OSX. Since my view is custom drawn I will not use IB and want to do it all in code. I created a subclass of NSButtonCell and a subclass of NSButton. In the Subclass of NSButtonCell I override the Method drawBezelWithFrame:inView: and in the initWithFrame Method of my subclassed NSButton I use setCell to set my CustomCell in the Button. However, drawBezelWithFrame gets not called and I don't understand why. Can someone point out what I've done wrong or what I miss here?
Subclass of NSButtonCell:
#import "TWIButtonCell.h"
#implementation TWIButtonCell
-(void)drawBezelWithFrame:(NSRect)frame inView:(NSView *)controlView
{
//// General Declarations
[[NSGraphicsContext currentContext] saveGraphicsState];
//// Color Declarations
NSColor* fillColor = [NSColor colorWithCalibratedRed: 0 green: 0.59 blue: 0.886 alpha: 1];
//// Rectangle Drawing
NSBezierPath* rectanglePath = [NSBezierPath bezierPathWithRect: NSMakeRect(8.5, 7.5, 85, 25)];
[fillColor setFill];
[rectanglePath fill];
[NSGraphicsContext restoreGraphicsState];
}
#end
Subclass of NSButton:
#import "TWIButton.h"
#import "TWIButtonCell.h"
#implementation TWIButton
- (id)initWithFrame:(NSRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
TWIButtonCell *cell = [[TWIButtonCell alloc]init];
[self setCell:cell];
}
return self;
}
- (void)drawRect:(NSRect)dirtyRect
{
// Drawing code here.
}
#end
Usage:
- (void)addSendButton:(NSRect)btnSendRectRect
{
TWIButton *sendButton = [[TWIButton alloc] initWithFrame:btnSendRectRect];
[self addSubview:sendButton];
[sendButton setTitle:#"Send"];
[sendButton setTarget:self];
[sendButton setAction:#selector(send:)];
}

Answer 1

Following are the things seems to be missing out from your code.
You are not calling the [super drawRect:dirtyRect]
You are not overriding + (Class)cellClass in the Class(TWIButton) which is derived from NSButton.
Below is the code after changes:
#implementation TWIButton
- (id)initWithFrame:(NSRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
TWIButtonCell *cell = [[TWIButtonCell alloc]init];
[self setCell:cell];
}
return self;
}
- (void)drawRect:(NSRect)dirtyRect
{
// Drawing code here.
//Changes Added!!!
[super drawRect:dirtyRect];
}
//Changes Added!!!!
+ (Class)cellClass
{
return [TWIButtonCell class];
}
#end
Now keep the break point at drawBezelWithFrame and check it will get called.

Answer 2

One might forgo the NSButton subclass, since it looks like you are ONLY using it to instantiate the Cell type within the initializer.
Simply
NSButton *button ...
[button setCell: [[TWIButtonCell alloc] init] autorelease]];
btw. you will probably have a leak in the previous examples since you init and then call setCell that likely has its own retain.