Custom background for UINavigationBar?

Nice, but there is something wrong with this solution.. actually drawrect is still painting when i decide to play a video using class MPMoviePlayerController ... I'm goiing crazy i cant find any workaround, does someone has an idea ?

Cheers,
Ju

i cant find any workaround

Perhaps preload, mask (& don't release) and then unmask instead? Sounds a bit like custom to me 🙂

I wasn't happy having to make each viewcontroller responsible for sending the background to the back in each its viewDidAppear methods, so I tried subclassing UINavigationBar instead. The UINavigationBar class uses the insertSubview:atIndex: method to insert new UIBarButtons etc. So each time this is called, we need to send our background to the back.

@interface MTNavigationBar : UINavigationBar
{
 UIImageView *bg;
}
-(void)setBackgroundImage:(UIImage*)image;
- (void)insertSubview:(UIView *)view atIndex:(NSInteger)index;
@end
@implementation MTNavigationBar
-(void)setBackgroundImage:(UIImage*)image {
 if(image == nil) return;
 bg = [[UIImageView alloc]initWithImage:image];
 bg.frame = CGRectMake(0.f, 0.f, self.frame.size.width, self.frame.size.height);
 [self addSubview:bg];
 [self sendSubviewToBack:bg];
 [bg release];
}
- (void)insertSubview:(UIView *)view atIndex:(NSInteger)index
{
 [super insertSubview:view atIndex:index];
 [self sendSubviewToBack:bg];
}
@end

Now, in my XIB file, I changed the class of the Navigation Bar to MTNavigationBar.
Since the UINavigationController class is still expecting a UINavigationBar in the navigationBar property, I needed to cast it explicitly whenever setting the background. E.g.:

[((MTNavigationBar*) navigationController.navigationBar) setBackgroundImage:[UIImage imageNamed:@"Header.png"]];

You can add an icon or a background this way as well:

UINavigationBar *navbar = [navigationTab1Controller navigationBar];
UIImage *im = [UIImage imageNamed:@"logo.png"];
UIImageView *animage = [[UIImageView alloc] initWithImage:im];

[navbar addSubview:animage];


Hope that helps!
Joe

This works, but has a few flaws:

1) Do NOT override existing methods in categories. This is what subclasses were invented for.

2) In drawing an image that can be repeated (like a gradient), use -drawAsPatternInRect: That way the iPhone does not have to scale but to repeat the image, which is faster.

3) When drawing inside a View, never ever refer to its frame, use its bounds! What you do here will only work in views whose origin is 0,0.

Try overriding - (void)drawRect:(CGRect)rect like so:

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



This works well for me, and doesn't appear to have issues with pushing new view controllers, hidden titles and bar button items, etc. I'm still fairly new at this, though 🙂

Hi,
Nice and quick tip..
I did this as well, it works nice as replacing the navbar image, but it covers the buttonItem (back button for example) when i push a new view controller in my navcontroller... the button is still here cause i can press it, but it is under the image... how can I have the button appear / or having the image as background only??

This works perfectly, however if you invoke a MPMoviePlayerController the image is also displayed at the top of the movie player. Apple then reject the application:

"3.3.1 Applications may only use Documented APIs in the manner prescribed by Apple and must not use or call any private APIs."

There is no documentation for the organization, layout, or subviews of the view hierarchy managed by MPMoviePlayerController in iPhone OS 3.1.2

.. have you an idea how I may prevent this happening?

hxela wrote:
"3.3.1 Applications may only use Documented APIs in the manner prescribed by Apple and must not use or call any private APIs."

There is no documentation for the organization, layout, or subviews of the view hierarchy managed by MPMoviePlayerController in iPhone OS 3.1.2

.. have you an idea how I may prevent this happening?

I ran into this issue with my app, and after a bit of trail and error, the obvious jumped out at me. Although I'm not sure if this is considered using a private api.

@implementation UINavigationBar (UINavigationBarCategory)
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx
{
 if([self isMemberOfClass: [UINavigationBar class]]){
 UIImage *image = [UIImage imageNamed:@"navBarBackground.png"];
 CGContextClip(ctx);
 CGContextTranslateCTM(ctx, 0, image.size.height);
 CGContextScaleCTM(ctx, 1.0, -1.0);
 CGContextDrawImage(ctx, CGRectMake(0, 0, self.frame.size.width, self.frame.size.height), image.CGImage);
 }else{
 [super drawLayer:layer inContext:ctx];
 }
}
@end

Based on what I found on this Q&A in regard to overriding drawLayer... I assume this should be safe:
http://developer.apple.com/iphone/library/qa/qa2009/qa1637.html

Thanks for this - your solution got me through the approval process

Great! Also, I found a small problem with the CGContextClip(ctx); Simply remove the line "CGContextClip(ctx);" to prevent doClip Errors from showing.

Message was edited by: ljonesATL

Collin Allen wrote:
Try overriding - (void)drawRect:(CGRect)rect like so:

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

This works well for me, and doesn't appear to have issues with pushing new view controllers, hidden titles and bar button items, etc. I'm still fairly new at this, though 🙂

Thanks a lot!!!
Works for me....

Message was edited by: iSens

Yes, this is a great solution.

One wrinkle: I'd like the navigation bar to be taller. I've tried setting a new frame size in the initWithCoder: method for UINavigationBar; also, resizing it, then calling setNeedsLayout, in in the view controller. Neither works.

Any ideas?

Thanks.