UINavigationBar渐变细节

Question

我试图重新创建一个UINavigationBar的外观。栏的背景是使用渐变绘制的，但尚不清楚默认颜色和点的内容。有人在这方面做过什么吗？

Answer 1

从我的一个项目。根据自己的喜好调整颜色。它还可以显示背景图片，如果你想（ImageReady中），否则它绘制导航栏像苹果的

//         #Lighter r,g,b,a   #Darker r,g,b,a 
#define MAIN_COLOR_COMPONENTS  { 0.153, 0.306, 0.553, 1.0, 0.122, 0.247, 0.482, 1.0 } 
#define LIGHT_COLOR_COMPONENTS  { 0.478, 0.573, 0.725, 1.0, 0.216, 0.357, 0.584, 1.0 } 

@implementation UINavigationBar (UINavigationBarCategory) 

- (void)drawRect:(CGRect)rect { 
    if (imageReady) { 
     UIImage *img = [UIImage imageNamed: @"navigation_background.png"]; 
     [img drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)]; 
    } else { 
     // Render yourself instead. 
     // You will need to adjust the MAIN_COLOR_COMPONENTS and LIGHT_COLOR_COMPONENTS to match your app 

     // emulate the tint colored bar 
     CGContextRef context = UIGraphicsGetCurrentContext(); 
     CGFloat locations[2] = { 0.0, 1.0 }; 
     CGColorSpaceRef myColorspace = CGColorSpaceCreateDeviceRGB(); 

     CGFloat topComponents[8] = LIGHT_COLOR_COMPONENTS; 
     CGGradientRef topGradient = CGGradientCreateWithColorComponents(myColorspace, topComponents, locations, 2); 
     CGContextDrawLinearGradient(context, topGradient, CGPointMake(0, 0), CGPointMake(0,self.frame.size.height/2), 0); 
     CGGradientRelease(topGradient); 

     CGFloat botComponents[8] = MAIN_COLOR_COMPONENTS; 
     CGGradientRef botGradient = CGGradientCreateWithColorComponents(myColorspace, botComponents, locations, 2); 
     CGContextDrawLinearGradient(context, botGradient, 
     CGPointMake(0,self.frame.size.height/2), CGPointMake(0, self.frame.size.height), 0); 
     CGGradientRelease(botGradient); 

     CGColorSpaceRelease(myColorspace); 


     // top Line 
     CGContextSetRGBStrokeColor(context, 1, 1, 1, 1.0); 
     CGContextMoveToPoint(context, 0, 0); 
     CGContextAddLineToPoint(context, self.frame.size.width, 0); 
     CGContextStrokePath(context); 

     // bottom line 
     CGContextSetRGBStrokeColor(context, 0, 0, 0, 1.0); 
     CGContextMoveToPoint(context, 0, self.frame.size.height); 
     CGContextAddLineToPoint(context, self.frame.size.width, self.frame.size.height); 
     CGContextStrokePath(context); 
    } 
} 

@end