Question

使用以下代码设置UINavigationBar的外观，但在我的情况下，当视图控制器第一次显示时，它未设置。我只需要推动另一个视图控制器然后设置它。

UIImage *gradientImage44 = [[UIImage imageNamed:@"navigationBar44"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 0)];

UIImage *gradientImage32 = [[UIImage imageNamed:@"navigationBar32"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 0)];

[[UINavigationBar appearance] setBackgroundImage:gradientImage44 forBarMetrics:UIBarMetricsDefault];
[[UINavigationBar appearance] setBackgroundImage:gradientImage32 forBarMetrics:UIBarMetricsLandscapePhone];

Answer 1

有不同的方法可以为ios 5及以上版本设置Uinavigationbar背景图像，并且ios低于ios 5

对于ios 5，您可以在app delegate中使用以下代码

//Customize the look of the UINavBar for iOS5 devices
 UIImage *gradientImage44 = [[UIImage imageNamed:@"navigationBar44"]   
 resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 0)];

UIImage *gradientImage32 = [[UIImage imageNamed:@"navigationBar32"]    
resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 0)];

 [[UINavigationBar appearance] setBackgroundImage:gradientImage44 
 forBarMetrics:UIBarMetricsDefault];

 [[UINavigationBar appearance] setBackgroundImage:gradientImage32 
  forBarMetrics:UIBarMetricsLandscapePhone];

但如果您使用的任何ios版本低于ios 5，则必须继承UINavigationControl并重载drawRect，如

@interface CustomNavigationBar : UINavigationBar
 @end

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

// this can go anywhere
+(UINavigationController*) myCustomNavigationController
  {
   YOurViewController *vc = [[[YOurViewController alloc] init] autorelease];
   UINavigationController *nav = [[[NSBundle mainBundle] 
   loadNibNamed:@"CustomNavigationController" owner:self options:nil] objectAtIndex:0];
   nav.viewControllers = [NSArray arrayWithObject:vc];
   return nav;
 }

像这样，您可以自定义导航栏，并且对所有ios版本都有效。

您可以使用

检查ios 5

if ([[UINavigationBar class]respondsToSelector:@selector(appearance)]) {
   ///ios 5 and above.
 }

首次显示视图控制器时未设置UINavigationBar外观

1 个答案: