自定义uinavigatonbar异常 [英] Custom uinavigatonbar exception

问题描述

我通过这种方式制作了一个自定义的uinavigation栏:

I've made a custom uinavigation bar this way:

@implementation UINavigationBar (UINavigationBarCategory)

- (void)drawRect:(CGRect)rect {
        UIImage *img = [UIImage imageNamed: @"navigation_background.png"];
        [img drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
}

@end

现在，当我将特定的viewcontroller加载到de navigationcontroller中时，我想添加例外以显示正常的uinavigation栏.

Now I'd like to add exception to show the normal uinavigation bar when i load an specific viewcontroller into de navigationcontroller.

如何编码该异常?

推荐答案

我认为对于 UINavigationBar 上的类别，这是不可能的.我会建议一个子类，例如 CustomNavigationBar

I don't think that's possible with a category on UINavigationBar. I would suggest a subclass, say CustomNavigationBar

.h

#import <UIKit/UIKit.h>

@interface CustomNavigationBar : UINavigationBar {
}
@end

.m

#import "CustomNavigationBar.h"

@implementation CustomNavigationBar

- (void)drawRect:(CGRect)rect {
        UIImage *img = [UIImage imageNamed: @"navigation_background.png"];
        [img drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
}

@end

棘手的事情是，您永远不会自己创建 UINavigationBar ，这全部由UIKit处理.要仅更改某些栏的外观，您必须在运行时手动更改它们的类.

The tricky thing is that you never create a UINavigationBar yourself, it's all handled by UIKit. To change the appearance of some bars only, you'll have to manually change their class at runtime.

导入

#import <objc/runtime.h>

然后在您的视图控制器中(例如在viewDidLoad中)添加

And in your view controller (in viewDidLoad for example), add

object_setClass(self.navigationController.navigationBar, [CustomNavigationBar class]);

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