UINavigationBar的的drawRect没有在安装iOS 5.0被称为 [英] UINavigationBar's drawRect is not called in iOS 5.0

问题描述

我overrided（放置于类别或交叉混合）UINavigationBar的的drawRect显示自定义背景。在iOS 5中它不工作。我应该怎么办？

I've overrided(placed in category, or swizzled) UINavigationBar's drawRect to show custom background. In iOS 5 it's not working. What should I do?

推荐答案

有一些可能的解决方案：

There's some possible solutions:

最快的修为最懒惰的我们：

Quickest fix For laziest of us :

@interface MyNavigationBar : UINavigationBar

@end

@implementation MyNavigationBar

- (void)drawRect:(CGRect)rect {

}

@end

@implementation UINavigationBar (BecauseIMLazyHacks)
/*
 Another Ugly hack for iOS 5.0 support
*/
+ (Class)class {
  return NSClassFromString(@"MyNavigationBar");
}

-(void)drawRect:(CGRect)rect {

  CGContextRef context = UIGraphicsGetCurrentContext();
  CGContextTranslateCTM(context, 0, self.frame.size.height);
  CGContextScaleCTM(context, 1.0, -1.0);

  CGContextDrawImage(context, CGRectMake(0, 0, 
  self.frame.size.width, self.frame.size.height), barBackground.CGImage);      

}
@end

再。它的工作原理，但你不应该做这样的。

Again. It works, but You shouldn't do it like this.

的另一种方法，如在WWDC'11建议是覆盖UINavigationBar的（创建MyNavigationBar）和从XIB初始化的UINavigationController像这里：

Another way, as suggested in WWDC'11 is to override UINavigationBar (Create MyNavigationBar) and initialize UINavigationController from xib like here :

<一个href=\"http://www.iosdevnotes.com/2011/09/custom-uinavigationbars-techniques/\">http://www.iosdevnotes.com/2011/09/custom-uinavigationbars-techniques/

最后，使用了iOS5.0和iOS5.0-逻辑流量开关
使用新的API，它是可能的。

And finally, use logic flow switch for iOS5.0 and iOS5.0- Use new API where it's possible.

分类是错误的道路，交叉混合是走错了路。 （他们只是在耳语你的耳朵：，给自己的黑暗面是你可以保存你的应用程序的唯一方法）

Categories is wrong path, Swizzling is wrong path. (They're just whispering in your ears:"Give yourself to the Dark Side. It is the only way you can save your apps.")

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