iPhone导航栏图像

Question

I'd like to replace the back button and the entire navigation bar in my iPhone app with custom images. First of all, is this possible? Second, if so, how? Thanks.

Answer 1

This code will modify every UINavigationBar in your app.

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

Answer 2

You can use this code to change navigation bar image and tab bar image to your custom images:

   if([[UINavigationBar class] respondsToSelector:@selector(appearance)])  {//iOS >=5.0
    UIImage *image = [UIImage imageNamed:@"myCustomImage.png"];

    CGSize newSize = CGSizeMake(self.navigationController.navigationBar.frame.size.width, self.navigationController.navigationBar.frame.size.height);
    UIGraphicsBeginImageContext(newSize);
    [image drawInRect: CGRectMake(0, 0, self.navigationController.navigationBar.frame.size.width, self.navigationController.navigationBar.frame.size.height)];


    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    [self.navigationController.navigationBar   setBackgroundImage:newImage  forBarMetrics:UIBarMetricsDefault];

    [[UIToolbar appearance] setBackgroundImage:newImage forToolbarPosition:UIToolbarPositionAny barMetrics:UIBarMetricsDefault];
    [[UITabBar appearance] setBackgroundImage:newImage];
    [[UITabBar appearance] setSelectedImageTintColor:[UIColor cyanColor]];
}

Answer 3

You won't be able to override the look and feel of Apple's navigation bar easily, and even if you are able to, there's a good chance it will go against their policy of avoiding private API's. However, it is pretty simple to create your own look-alike navigation bar using all custom images. This would work well for simple one-off screens that need the navigation bar, but will be a beast to implement on a complex UINavigationController-based hierarchy.

Edit: It looks like people have been able to change the background by overriding the -drawRect selector: Custom background for UINavigationBar? . I don't see any reports of whether or not the changes were approved for the App Store.