cocoa - Subclass NSView to change background color

Question

I want to change the background color of a custom view. I have a subclass NSView something like that:

#import <Cocoa/Cocoa.h>
@interface CustomBGView : NSView {
NSColor myColor; 
} @end

and the .m

  @implementation CustomBGView

  - (void)drawRect:(NSRect)rect
  {
    [myColor set];
    NSRectFill([self bounds]);
  }

  - (void)changeColor:(NSColor*) aColor
 {
    myColor = aColor;
 }

The changeColor method is for change color in the app controller. I also define a IBOutlet for the custom view called myView binded in IB.

The problem is when I use changeColor in the app controller like this:

[myView changeColor: [NSColor colorWithCalibratedRed:0.5 green:0.5 blue:0.5 alpha:1.0]];

There is a 'Program received signal: “EXC_BAD_ACCESS”. If I use instead something like this:

[myView changeColor: [NSColor whiteColor]];

works fine.

Where is the Problem? Thanks in advance

---

Thanks Chuck! Now with "retain" works fine.

And why it works without retain in one case ([myView changeColor: [NSColor whiteColor]];) and not in the other???

Answer 1

You're storing the argument to changeColor: in an instance variable, but not retaining it, so you don't own it and it thinks it can go away.