给 UINavigationBar 设置背景图片的最简单方法

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利用objective-c的Category语法扩展UINavigationBar 类

具体代码为

@implementation UINavigationBar (UINavigationBarCategory)

- (void)drawRect:(CGRect)rect {
// Drawing code
UIImage *img = [UIImage imageNamed: @"navbar_background.png"];
CGPoint point = {0,0};

[img drawAtPoint:point];

}
@end

////////////////////方法2////////////////////////////////////////////////////

@implementation UINavigationBar (UINavigationBarCategory)

- (void)drawRect:(CGRect)rect {

//加入旋转坐标系代码

// Drawing code

UIImage *navBarImage = [UIImage imageNamed:@"LOGO_320×44.png"];

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextTranslateCTM(context, 0.0, self.frame.size.height);

CGContextScaleCTM(context, 1.0, -1.0);

CGPoint center=self.center;

CGImageRef cgImage= CGImageCreateWithImageInRect(navBarImage.CGImage,CGRectMake(0, 0, 1, 44));

CGContextDrawImage(context, CGRectMake(center.x-160-80, 0, 80,self.frame.size.height), cgImage);

CGContextDrawImage(context, CGRectMake(center.x-160, 0, 320,self.frame.size.height), navBarImage.CGImage);

CGContextDrawImage(context, CGRectMake(center.x+160, 0, 80,self.frame.size.height), cgImage);

}

@end

old code

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