Darker iOS7 translucent UINavigationBar

AMPNavigationBar.m

// .h

@interface AMPNavigationBar : UINavigationBar

@property (nonatomic, assign) CGFloat extraColorLayerOpacity UI_APPEARANCE_SELECTOR;

@end

// .m

@interface AMPNavigationBar ()

@property (nonatomic, strong) CALayer *extraColorLayer;

@end

static CGFloat const kDefaultColorLayerOpacity = 0.5f;

@implementation AMPNavigationBar

- (void)setBarTintColor:(UIColor *)barTintColor
{
  [super setBarTintColor:barTintColor];
	if (self.extraColorLayer == nil) {
		// this all only applies to 7.0 - 7.0.2
		if ([[[UIDevice currentDevice] systemVersion] compare:@"7.0.3" options:NSNumericSearch] == NSOrderedAscending) {
			self.extraColorLayer = [CALayer layer];
			self.extraColorLayer.opacity = self.extraColorLayerOpacity;
			[self.layer addSublayer:self.extraColorLayer];
		}
	}
	self.extraColorLayer.backgroundColor = barTintColor.CGColor;
}

- (void)layoutSubviews
{
  [super layoutSubviews];
	if (self.extraColorLayer != nil) {
		[self.extraColorLayer removeFromSuperlayer];
		self.extraColorLayer.opacity = self.extraColorLayerOpacity;
		[self.layer insertSublayer:self.extraColorLayer atIndex:1];
		CGFloat spaceAboveBar = self.frame.origin.y;
		self.extraColorLayer.frame = CGRectMake(0, 0 - spaceAboveBar, CGRectGetWidth(self.bounds), CGRectGetHeight(self.bounds) + spaceAboveBar);
	}
}

- (void)setExtraColorLayerOpacity:(CGFloat)extraColorLayerOpacity
{
  _extraColorLayerOpacity = extraColorLayerOpacity;
	[self setNeedsLayout];
}

#pragma mark - NSCoding

- (id)initWithCoder:(NSCoder *)decoder
{
    self = [super initWithCoder:decoder];
    if (self) {
        _extraColorLayerOpacity = [[decoder decodeObjectForKey:@"extraColorLayerOpacity"] floatValue];
    }
    return self;
}

- (void)encodeWithCoder:(NSCoder *)encoder
{
	[super encodeWithCoder:encoder];
	[encoder encodeObject:@(self.extraColorLayerOpacity) forKey:@"extraColorLayerOpacity"];
}

@end

// the easy way to use it is to subclass UINavigationController and override:
- (id)initWithRootViewController:(UIViewController *)rootViewController
{
  self = [super initWithNavigationBarClass:[APNavigationBar class] toolbarClass:[UIToolbar class]];
  if (self) {
    self.viewControllers = @[ rootViewController ];
  }
  return self;
}

Don't forget to add

[[APNavigationBar appearance] setExtraColorLayerOpacity:0.5f];

when you call it!

Maybe we can remove kDefaultColorLayerOpacity since it not used anymore.

Nice work. Trying to figure out how to get this to work with UINavigationControllers created in a Storyboard. Not sure it's possible.

Your subclass of UINavigationController will have:

• (id)initWithCoder:(NSCoder *)decoder

called when the subclass is created, but you don't have the opportunity to set the UINavigationBar at that time.

Thanks, great solution! Whenever I go into a subview or scroll the current view, though, the opacity seems to change after about 1 second. Is it supposed to do that? If so, how can I disable it?

https://gist.github.com/j-mcnally/6987297

I didnt want to have to go over every single class and change the subclass so i went with the swizzing approach, id love if someone wanted to implement this to the original spec, its late and i only need it to be one color and one opacity ever, but wanted to get thoughts about potential pitfalls.

This fails when the device is rotated to landscape orientation. Instead of computing spaceAboveBar from the bar's frame, its better to get the status bar's height directly using CGRectGetHeight([[UIApplication sharedApplication] statusBarFrame]). Fork here: https://gist.github.com/chaitanyagupta/7024530

check the new comment, 7.0.3 changed things again. I'm only using the backing layer pre 7.0.3. For everything later a color with an alpha (I'm using .91 on blackColor) seems to be a better approach.