问题
How do you make a UINavigationBar transparent? Though I want its bar items to remain visible.
回答1:
If anybody is wondering how to achieve this in iOS 7+, here's a solution (iOS 6 compatible too)
In Objective-C
[self.navigationBar setBackgroundImage:[UIImage new]
forBarMetrics:UIBarMetricsDefault];
self.navigationBar.shadowImage = [UIImage new];
self.navigationBar.translucent = YES;
In swift 3 (iOS 10)
self.navigationBar.setBackgroundImage(UIImage(), for: .default)
self.navigationBar.shadowImage = UIImage()
self.navigationBar.isTranslucent = true
In swift 2
self.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: .Default)
self.navigationBar.shadowImage = UIImage()
self.navigationBar.translucent = true
Discussion
Setting translucent to YES on the navigation bar does the trick, due to a behavior discussed in the UINavigationBar documentation. I'll report here the relevant fragment:
If you set this property to
YESon a navigation bar with an opaque custom background image, the navigation bar will apply a system opacity less than 1.0 to the image.
回答2:
In iOS5 you can do this to make the navigation bar transparent:
nav.navigationBar.translucent = YES; // Setting this slides the view up, underneath the nav bar (otherwise it'll appear black)
const float colorMask[6] = {222, 255, 222, 255, 222, 255};
UIImage *img = [[UIImage alloc] init];
UIImage *maskedImage = [UIImage imageWithCGImage: CGImageCreateWithMaskingColors(img.CGImage, colorMask)];
[nav.navigationBar setBackgroundImage:maskedImage forBarMetrics:UIBarMetricsDefault];
[img release];
回答3:
From IOS7 :
self.navigationController.navigationBar.translucent = YES;
self.navigationController.navigationBar.shadowImage = [UIImage new];
self.navigationController.view.backgroundColor = [UIColor clearColor];
[self.navigationController.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
self.navigationController.navigationBar.backgroundColor = [UIColor clearColor];
回答4:
For anyone who wants to do this in Swift 2.x:
self.navigationController?.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: .Default)
self.navigationController?.navigationBar.shadowImage = UIImage()
self.navigationController?.navigationBar.translucent = true
or Swift 3.x:
self.navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
self.navigationController?.navigationBar.shadowImage = UIImage()
self.navigationController?.navigationBar.isTranslucent = true
回答5:
This seems to work:
@implementation UINavigationBar (custom)
- (void)drawRect:(CGRect)rect {}
@end
navigationController.navigationBar.backgroundColor = [UIColor clearColor];
回答6:
After doing what everyone else said above, i.e.:
navigationController?.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: .default)
navigationController?.navigationBar.shadowImage = UIImage()
navigationController!.navigationBar.isTranslucent = true
... my navigation bar was still white. So I added this line:
navigationController?.navigationBar.backgroundColor = .clear
... et voila! That seemed to do the trick.
回答7:
I know this topic is old, but if people want to know how its done without overloading the drawRect method.
This is what you need:
self.navigationController.navigationBar.translucent = YES;
self.navigationController.navigationBar.opaque = YES;
self.navigationController.navigationBar.tintColor = [UIColor clearColor];
self.navigationController.navigationBar.backgroundColor = [UIColor clearColor];
回答8:
The below code expands upon the top answer chosen for this thread, to get rid of the bottom border and set text color:
The last two coded lines of this code set transparency. I borrowed that code from this thread and it worked perfectly!
The "clipsToBounds" property was code I found which got rid of the bottom border line with OR without transparency set (so if you decide to go with a solid white/black/etc. background instead, there will still be no border line).
The "tintColor" line (2nd coded line) set my back button to a light grey
I kept barTintColor as a backup. I don't know why transparency would not work, but if it doesn't, I want my bg white as I used to have it
let navigationBarAppearace = UINavigationBar.appearance() navigationBarAppearace.tintColor = UIColor.lightGray navigationBarAppearace.barTintColor = UIColor.white navigationBarAppearace.clipsToBounds = true navigationBarAppearace.isTranslucent = true navigationBarAppearace.setBackgroundImage(UIImage(), for: .default) navigationBarAppearace.shadowImage = UIImage()
回答9:
C# / Xamarin Solution
NavigationController.NavigationBar.SetBackgroundImage(new UIImage(), UIBarMetrics.Default);
NavigationController.NavigationBar.ShadowImage = new UIImage();
NavigationController.NavigationBar.Translucent = true;
回答10:
Try the following piece of code:
self.navigationController.navigationBar.translucent = YES;
回答11:
for Swift 3.0:
override func viewDidLoad() {
super.viewDidLoad()
navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
navigationController?.navigationBar.shadowImage = UIImage()
navigationController?.navigationBar.isTranslucent = true
}
回答12:
Another Way That worked for me is to Subclass UINavigationBar And leave the drawRect Method empty !!
@IBDesignable class MONavigationBar: UINavigationBar {
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func drawRect(rect: CGRect) {
// Drawing code
}}
回答13:
In Swift 4.2
self.navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
self.navigationController?.navigationBar.shadowImage = UIImage()
self.navigationController?.navigationBar.isTranslucent = true
(in viewWillAppear), and then in viewWillDisappear, to undo it, put
self.navigationController?.navigationBar.shadowImage = nil
self.navigationController?.navigationBar.isTranslucent = false
回答14:
Do you mean entirely transparent, or using the translucent-black style seen in the Photos app? The latter you can accomplish by setting its barStyle property to UIBarStyleBlackTranslucent. The former... I'm not sure about. If you want the items on it to still be visible, you might have to do some digging around in the bar's view hierarchy and remove the view containing its background.
回答15:
This works for Swift 2.0.
navigationController!.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: UIBarMetrics.Default)
navigationController!.navigationBar.shadowImage = UIImage()
navigationController!.navigationBar.translucent = true
回答16:
Check RRViewControllerExtension, which is dedicated on UINavigation bar appearance management.
with RRViewControllerExtension in your project, you just need to override
-(BOOL)prefersNavigationBarTransparent;
in you viewcontroller.
回答17:
extension UINavigationBar {
var isTransperent: Bool {
get {
return false // Just to satisfy property
}
set {
if newValue == true {
self.shadowImage = UIImage()
self.isTranslucent = true
self.setBackgroundImage(UIImage(), for: .default)
}else{
self.shadowImage = UIImage()
self.isTranslucent = false
self.setBackgroundImage(nil, for: .default)
}
}
}
}
来源：https://stackoverflow.com/questions/2315862/make-uinavigationbar-transparent