将图像添加到iPhone导航栏

Question

I want to replace the current nav bar with a custom image. How my code is structured is that a tab bar controller controls a bunch of navigation controllers which contain views (tab bar controller -> nav controller -> view). I tried using this code in my app delegate

@implementation UINavigationBar (UINavigationBarCategory)
- (void)drawRect:(CGRect)rect {
  UIColor *color = [UIColor blackColor];
  UIImage *img  = [UIImage imageNamed: @"nav.png"];
  [img drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
  self.tintColor = color;
}
@end

But it did not work. Any ideas why? Should I have placed it somewhere else? Thanks!

Answer 1

如果您使用的是iOS 5，则可以在每次初始化导航控制器（此示例中为aNavigationController）的地方使用setBackgroundImage :：

[aNavigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"nav.png"] forBarMetrics:UIBarMetricsDefault];

Answer 2

I would not use a category. I would subclass UINavigationBar instead. See this: https://stackoverflow.com/a/6959354/472344

If you are targeting iOS 5 or up, use @BJH's solution instead.