带有自定义背景图像的 UINavigationbar
我有一个自定义类别，可以根据我所在的视图为我的导航栏定义特殊的背景图像。
在类别中，我使用设置图像。
- (void)drawRect:(CGRect)rect
事情是，当在导航控制器中浏览我的视图时，自定义图像会消失，留下320x44（条的大小）的空白区域，直到下一个控制器重新出现 - 即大约 1 秒后。
这种看起来很难看，我想知道是否有更好的方法来做到这一点，所以我有一个干净的实现，看起来也不错并且符合我的要求。
提前致谢。
类别代码：
- (void)initImageDictionary
{
if(navigationBarImages==NULL){
navigationBarImages=[[NSMutableDictionary alloc] init];
}
}
- (void)drawRect:(CGRect)rect
{
UIImage *imageName = [navigationBarImages objectForKey:[NSValue valueWithNonretainedObject: self]];
UIImage *image = imageName;
[image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
}
- (void)setMyImage:(UIImage*)image
{
[navigationBarImages setObject:image forKey:[NSValue valueWithNonretainedObject: self]];
[self setNeedsDisplay];
}
然后我调用：
[self.navigationBar performSelectorInBackground:@selector(setMyImage:) withObject:[UIImage imageNamed:imageTopbar]];
I have a custom category to define a special background image for my navigationbar depending on the view I'm in.
Within the category I set the image using
- (void)drawRect:(CGRect)rect
The thing is, when navigating through my views in the Navigation Controller, the custom image disappears leaving a blank white space 320x44(size of the bar) until the next controller reappers - i.e. after about 1 second.
This sort of looks ugly and I was wondering whether there was a better way to do this so I have a clean implementation which looks nice aswell and fits my demands.
Thanks in advance.
Category Code:
- (void)initImageDictionary
{
if(navigationBarImages==NULL){
navigationBarImages=[[NSMutableDictionary alloc] init];
}
}
- (void)drawRect:(CGRect)rect
{
UIImage *imageName = [navigationBarImages objectForKey:[NSValue valueWithNonretainedObject: self]];
UIImage *image = imageName;
[image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
}
- (void)setMyImage:(UIImage*)image
{
[navigationBarImages setObject:image forKey:[NSValue valueWithNonretainedObject: self]];
[self setNeedsDisplay];
}
Then I call:
[self.navigationBar performSelectorInBackground:@selector(setMyImage:) withObject:[UIImage imageNamed:imageTopbar]];
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您应该仅在主线程上使用 UIKit。
You should use UIKit only on the main thread.
在您的 ViewController 中，尝试以下操作，其中 @"BGimage.png" 是您的图像文件：
//puts an image as bg pattern(tiles) for a View
//self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"BGimage.png"]];
In your ViewController, try this where @"BGimage.png" is your image file:
//puts an image as bg pattern(tiles) for a View
//self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"BGimage.png"]];