自定义NavigationBar的背景(兼容ios4)

iOS4

在AppDelegate.m的文件中加入如下定义，覆盖NavigationBar的drawRect函数：

 @interface UINavigationBar (CustomBackgroud)

 - (void)drawRect:(CGRect)rect;

 @end

 @implementation UINavigationBar (CustomBackgroud)

 // iOS 4.* 下替换导航条皮肤
 - (void)drawRect:(CGRect)rect
 {
     UIImage *navBarImg = [[UIImage imageNamed:@"nav_bar"] stretchableImageWithLeftCapWidth:1 topCapHeight:0.0];
     [navBarImg drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
 }

 @end

iOS5

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