Best point to overwrite the navigationBar property of navigationController

Question

Hi there,

I'm overwriting UINavigationController to replace the default navigationBar property with an instance of my own subclass of UINavigationBar. So I tried something like

_navigationBar = [[SBNavigationBar alloc] init];

in my -initWithRootViewController:. But that didn't work out as I expected it. There's still the default navigationBar being displayed.

So what's the best point to overwrite the navigationBar?

Thanks in advance
–f

Answer 1

If you check the documentation http://developer.apple.com/iphone/library/documentation/uikit/reference/UINavigationController_Class/Reference/Reference.html, you'll see that the navigationBar property is read-only.

To have a custom navigationBar you can use Categories for example. You will find many questions answering this here on stackoverflow.

One simple version is putting an image in drawRect: like so...

@implementation UINavigationBar (Custom)

- (void)drawRect:(CGRect)rect {
    UIImage *image = [UIImage imageNamed: @"bg_toolbar.png"];
    [image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
}

@end