How do I change the background of a UINavigationBar?

I'd like to change the background of my UINavigationBar to 开发者_StackOverflowa [UIColor colorWithImage:], but it isn't working. What am I missing?

EDIT:

Once I've created my subclass, where do I set the UINavigationController to use it?

You can use the tintColor property to change the colour of a UINavigationBar, but to set an image as the background you'll have to provide your own UINavigationBar subclass and override the drawRect: method, for example:

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

If you use Interface Builder to build your UI then to use the custom navigation bar, just select the UINavigationBar element in Interface Builder, open the Inspector and in the Identity tab specify your UINavigationBar subclass in the class field, like so:

To have an image in the navigation bar, you have to draw it yourself, which actually isn't that hard. Save this as UINavigationBar+CustomBackground.m (it adds a custom category to UINavigationBar):

@implementation UINavigationBar (CustomBackground)

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

@end