使 UINavigationBar 透明

Question

How do you make a UINavigationBar transparent ? Though I want its bar items to remain visible.

Answer 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 YES on a navigation bar with an opaque custom background image, the navigation bar will apply a system opacity less than 1.0 to the image.

Answer 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];

Answer 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];

Answer 4

If you build with the latest beta iOS 13.4 and Xcode 11.4, the accepted answer won't work anymore. I've found another way, maybe it's just a bug in the beta software, but I'm writing it down there, just in case

(swift 5)

import UIKit

class TransparentNavBar :UINavigationBar {
    override func awakeFromNib() {
        super.awakeFromNib()
        self.setBackgroundImage(UIImage(), for: .default)
        self.shadowImage = UIImage()
        self.isTranslucent = true
        self.backgroundColor = .clear
        if #available(iOS 13.0, *) {
            self.standardAppearance.backgroundColor = .clear
            self.standardAppearance.backgroundEffect = .none
            self.standardAppearance.shadowColor = .clear
        }
    }
}

Answer 5

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

Answer 6

This seems to work:

@implementation UINavigationBar (custom)
- (void)drawRect:(CGRect)rect {}
@end

navigationController.navigationBar.backgroundColor = [UIColor clearColor];

Answer 7

After doing what everyone else said above, ie:

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.

Answer 8

The below code expands upon the top answer chosen for this thread, to get rid of the bottom border and set text color:

1. The last two coded lines of this code set transparency. I borrowed that code from this thread and it worked perfectly!

2. 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).

3. The "tintColor" line (2nd coded line) set my back button to a light grey

4. 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()

Answer 9

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];

Answer 10

Solution - Swift 5 - iOS 13+

According to the documentation , in your UIViewController subclass:

override func viewDidLoad()
{
    super.viewDidLoad()
    
    let appearance = UINavigationBarAppearance()
    appearance.configureWithTransparentBackground()
    //appearance.backgroundColor = UIColor.clear
    
    navigationItem.compactAppearance = appearance
    navigationItem.scrollEdgeAppearance = appearance
    navigationItem.standardAppearance = appearance
    
    //...
}

Just to be clear, this makes the UINavigationBar completely transparent . The bar button items are still visible and work properly.

What didn't work

override func viewDidLoad()
{
    super.viewDidLoad()
    
    navigationController?.navigationBar.isTranslucent = true
    navigationController?.navigationBar.isOpaque = false

    //...
}

This made me realize I didn't actually know the difference between transparent and translucent RIP.

References

https://developer.apple.com/documentation/uikit/uinavigationcontroller/customizing_your_app_s_navigation_bar

https://www.lexico.com/en/definition/transparent

https://www.lexico.com/en/definition/translucent

Update 08/10/2021

Changing the navigationItem bar buttons after setting the appearance in the way I provided will reset the appearance and you'll have to do it again.

Answer 11

C# / Xamarin Solution

NavigationController.NavigationBar.SetBackgroundImage(new UIImage(), UIBarMetrics.Default);
NavigationController.NavigationBar.ShadowImage = new UIImage();
NavigationController.NavigationBar.Translucent = true;

Answer 12

for Swift 3.0:

override func viewDidLoad() {
    super.viewDidLoad()

    navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
    navigationController?.navigationBar.shadowImage = UIImage()
    navigationController?.navigationBar.isTranslucent = true
}

Answer 13

试试下面的一段代码：

self.navigationController.navigationBar.translucent = YES;

Answer 14

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
}}

Answer 15

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

Answer 16

This worked with Swift 5.

// Clear the background image.
navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)

// Clear the shadow image.
navigationController?.navigationBar.shadowImage = UIImage()

// Ensure the navigation bar is translucent.
navigationController?.navigationBar.isTranslucent = true

Answer 17

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.

Answer 18

This works for Swift 2.0.

navigationController!.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: UIBarMetrics.Default)
navigationController!.navigationBar.shadowImage = UIImage()
navigationController!.navigationBar.translucent = true

Answer 19

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.

Answer 20

Swift 5<\/strong> :: Calling below in AppDelegate's didFinishLaunchingWithOptions function does the trick (This will be applied to your all navigationBars though, don't forget to switch your view controllers)

let navBarAppearance = UINavigationBarAppearance()
navBarAppearance.configureWithTransparentBackground()
            
navigationController?.navigationBar.standardAppearance = navBarAppearance
navigationController?.navigationBar.scrollEdgeAppearance = navBarAppearance

Answer 21

extension UINavigationBar {
var isTransperent: Bool {
        get {
            return false // Just to satisfy property
        }
        set {
            if newValue {
                self.shadowImage = UIImage()
                self.isTranslucent = true
                self.setBackgroundImage(UIImage(), for: .default)
            } else {
                self.shadowImage = UIImage()
                self.isTranslucent = false
                self.setBackgroundImage(nil, for: .default)
            }
        }
    }
}