问题

I have an app that sometimes needs its navigation bar to blend in with the content.

Does anyone know how to get rid of or to change color of this annoying little bar?

On the image below situation i have - i\'m talking about this 1px height line below \"Root View Controller\"

$\"enter$

回答1:

For iOS 13:

Use the .shadowColor property

If this property is nil or contains the clear color, the bar displays no shadow

For iOS 12 and below:

To do this, you should set a custom shadow image. But for the shadow image to be shown you also need to set a custom background image, quote from Apple's documentation:

For a custom shadow image to be shown, a custom background image must also be set with the setBackgroundImage(_:for:) method. If the default background image is used, then the default shadow image will be used regardless of the value of this property.

So:

let navigationBar = navigationController!.navigationBar
navigationBar.setBackgroundImage(#imageLiteral(resourceName: "BarBackground"),
                                                        for: .default)
navigationBar.shadowImage = UIImage()

Above is the only "official" way to hide it. Unfortunately, it removes bar's translucency.

I don't want background image, just color

You have those options:

Solid color, no translucency:

navigationBar.barTintColor = UIColor.redColor()
navigationBar.isTranslucent = false
navigationBar.setBackgroundImage(UIImage(), for: .default)
navigationBar.shadowImage = UIImage()

Create small background image filled with color and use it.
Use 'hacky' method described below. It will also keep bar translucent.

How to keep bar translucent?

To keep translucency you need another approach, it looks like a hack but works well. The shadow we're trying to remove is a hairline UIImageView somewhere under UINavigationBar. We can find it and hide/show it when needed.

Instructions below assume you need hairline hidden only in one controller of your UINavigationController hierarchy.

Declare instance variable:

private var shadowImageView: UIImageView?

Add method which finds this shadow (hairline) UIImageView:

private func findShadowImage(under view: UIView) -> UIImageView? {
    if view is UIImageView && view.bounds.size.height <= 1 {
        return (view as! UIImageView)
    }

    for subview in view.subviews {
        if let imageView = findShadowImage(under: subview) {
            return imageView
        }
    }
    return nil
}

Add/edit viewWillAppear/viewWillDisappear methods:

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    if shadowImageView == nil {
        shadowImageView = findShadowImage(under: navigationController!.navigationBar)
    }
    shadowImageView?.isHidden = true
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)

    shadowImageView?.isHidden = false
}

The same method should also work for UISearchBar hairline, and (almost) anything else you need to hide :)

Many thanks to @Leo Natan for the original idea!

回答2:

Below can help simply!

Swift:

self.navigationController?.navigationBar.setValue(true, forKey: "hidesShadow")

Objective C:

[self.navigationController.navigationBar setValue:@(YES) forKeyPath:@"hidesShadow"];

回答3:

If you just want to use a solid navigation bar color and have set this up in your storyboard, use this code in your AppDelegate class to remove the 1 pixel border via the appearance proxy:

[[UINavigationBar appearance] setBackgroundImage:[[UIImage alloc] init]
                                  forBarPosition:UIBarPositionAny
                                      barMetrics:UIBarMetricsDefault];

[[UINavigationBar appearance] setShadowImage:[[UIImage alloc] init]];

回答4:

Try this:

[[UINavigationBar appearance] setBackgroundImage: [UIImage new]  
                                   forBarMetrics: UIBarMetricsDefault];

[UINavigationBar appearance].shadowImage = [UIImage new];

Below image has the explanation (iOS7 NavigationBar):

And check this SO question: iOS7 - Change UINavigationBar border color

回答5:

Wanted to add the Swift version of Serhii's answer. I created a UIBarExtension.swift with the following:

import Foundation
import UIKit

extension UINavigationBar {
    func hideBottomHairline() {
        self.hairlineImageView?.isHidden = true
    }

    func showBottomHairline() {
        self.hairlineImageView?.isHidden = false
    }
}

extension UIToolbar {
    func hideBottomHairline() {
        self.hairlineImageView?.isHidden = true
    }

    func showBottomHairline() {
        self.hairlineImageView?.isHidden = false
    }
}

extension UIView {
    fileprivate var hairlineImageView: UIImageView? {
        return hairlineImageView(in: self)
    }

    fileprivate func hairlineImageView(in view: UIView) -> UIImageView? {
        if let imageView = view as? UIImageView, imageView.bounds.height <= 1.0 {
            return imageView
        }

        for subview in view.subviews {
            if let imageView = self.hairlineImageView(in: subview) { return imageView }
        }

        return nil
    }
}

回答6:

The swift way to do it:

UINavigationBar.appearance().setBackgroundImage(
    UIImage(),
    forBarPosition: .Any,
    barMetrics: .Default)

UINavigationBar.appearance().shadowImage = UIImage()

回答7:

Simple solution in swift

   let navigationBar = self.navigationController?.navigationBar
    navigationBar?.setBackgroundImage(UIImage(), forBarPosition: UIBarPosition.Any, barMetrics: UIBarMetrics.Default)
    navigationBar?.shadowImage = UIImage()

回答8:

After studying the answer from Serhil, I created a pod UINavigationBar+Addition that can easily hide the hairline.

#import "UINavigationBar+Addition.h"

- (void)viewDidLoad {
    [super viewDidLoad];

    UINavigationBar *navigationBar = self.navigationController.navigationBar;
    [navigationBar hideBottomHairline];
}

回答9:

In Swift 3.0

Edit your AppDelegate.swift by adding the following code to your application function:

// Override point for customization after application launch.

// Remove border in navigationBar
UINavigationBar.appearance().shadowImage = UIImage()
UINavigationBar.appearance().setBackgroundImage(UIImage(), for: .default)

回答10:

pxpgraphics' solution updated for Swift 2.0

extension UINavigationBar {

    func hideBottomHairline()
    {
        hairlineImageViewInNavigationBar(self)?.hidden = true
    }

    func showBottomHairline()
    {
        hairlineImageViewInNavigationBar(self)?.hidden = false
    }

    private func hairlineImageViewInNavigationBar(view: UIView) -> UIImageView?
    {
        if let imageView = view as? UIImageView where imageView.bounds.height <= 1
        {
            return imageView
        }

        for subview: UIView in view.subviews
        {
            if let imageView = hairlineImageViewInNavigationBar(subview)
            {
                return imageView
            }
        }

        return nil
    }

}

extension UIToolbar
{

    func hideHairline()
    {
        let navigationBarImageView = hairlineImageViewInToolbar(self)?.hidden = true
    }

    func showHairline()
    {
        let navigationBarImageView = hairlineImageViewInToolbar(self)?.hidden = false
    }

    private func hairlineImageViewInToolbar(view: UIView) -> UIImageView?
    {
        if let imageView = view as? UIImageView where imageView.bounds.height <= 1
        {
            return imageView
        }

        for subview: UIView in view.subviews
        {
            if let imageView = hairlineImageViewInToolbar(subview)
            {
                return imageView
            }
        }

        return nil
    }

}

回答11:

Swift 4 //for hiding navigation bar shadow line

navigationController?.navigationBar.shadowImage = UIImage()

回答12:

Can also be hidden from Storyboard (working on Xcode 10.1)

By adding runtime attribute: hidesShadow - Boolean - True

回答13:

As of iOS 13 there is a system API to set or remove the shadow

UIKit uses shadowImage and the shadowColor property to determine the shadow's appearance. When shadowImage is nil, the bar displays a default shadow tinted according to the value in the shadowColor property. If shadowColor is nil or contains the clearColor color, the bar displays no shadow.

    let appearance = UINavigationBarAppearance()
    appearance.shadowImage = nil
    appearance.shadowColor = nil
    navigationController.navigationBar.standardAppearance = appearance

回答14:

I use a UINavigationBar extension that enables me to hide/show that shadow using the UIAppearance API or selecting which navigation bar has to hide/show that shadow using Storyboard (or source code). Here is the extension:

import UIKit

private var flatAssociatedObjectKey: UInt8 = 0

/*
  An extension that adds a "flat" field to UINavigationBar. This flag, when
  enabled, removes the shadow under the navigation bar.
 */
@IBDesignable extension UINavigationBar {
    @IBInspectable var flat: Bool {
        get {
            guard let obj = objc_getAssociatedObject(self, &flatAssociatedObjectKey) as? NSNumber else {
                return false
            }
            return obj.boolValue;
        }

        set {
            if (newValue) {
                let void = UIImage()
                setBackgroundImage(void, forBarPosition: .Any, barMetrics: .Default)
                shadowImage = void
            } else {
                setBackgroundImage(nil, forBarPosition: .Any, barMetrics: .Default)
                shadowImage = nil
            }
            objc_setAssociatedObject(self, &flatAssociatedObjectKey, NSNumber(bool: newValue),
                    objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }
    }
}

Now, to disable the shadow across all navigation bars you have to use:

UINavigationBar.appearance().flat = true

Or you can enable/disable this behavior using storyboards:

回答15:

Swift 4 Tested ONE LINE SOLUTION

In Viewdidload() Set Navigation controller's userdefault value true for key "hidesShadow"

override func viewDidLoad() {
    super.viewDidLoad()

    self.navigationController?.navigationBar.setValue(true, forKey: "hidesShadow")

}

回答16:

Another option if you want to preserve translucency and you don't want to subclass every UINavigationController in your app:

#import <objc/runtime.h>

@implementation UINavigationController (NoShadow)

+ (void)load {
    Method original = class_getInstanceMethod(self, @selector(viewWillAppear:));
    Method swizzled = class_getInstanceMethod(self, @selector(swizzled_viewWillAppear:));
    method_exchangeImplementations(original, swizzled);
}

+ (UIImageView *)findHairlineImageViewUnder:(UIView *)view {
    if ([view isKindOfClass:UIImageView.class] && view.bounds.size.height <= 1.0) {
        return (UIImageView *)view;
    }

    for (UIView *subview in view.subviews) {
        UIImageView *imageView = [self findHairlineImageViewUnder:subview];
        if (imageView) {
            return imageView;
        }
    }

    return nil;
}

- (void)swizzled_viewWillAppear:(BOOL)animated {
    UIImageView *shadow = [UINavigationController findHairlineImageViewUnder:self.navigationBar];
    shadow.hidden = YES;

    [self swizzled_viewWillAppear:animated];
}

@end

回答17:

Swift put this

UINavigationBar.appearance().setBackgroundImage(UIImage(), forBarPosition: .Any, barMetrics: .Default)
UINavigationBar.appearance().shadowImage = UIImage()

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool

回答18:

Slightly Swift Solution 
func setGlobalAppearanceCharacteristics () {
    let navigationBarAppearace = UINavigationBar.appearance()
    navigationBarAppearace.tintColor = UIColor.white
    navigationBarAppearace.barTintColor = UIColor.blue
    navigationBarAppearace.setBackgroundImage(UIImage(), for: UIBarMetrics.default)
    navigationBarAppearace.shadowImage = UIImage()

}

回答19:

Solution in Swift 4.2:

private func removeHairlineFromNavbar() {
    UINavigationBar.appearance().setBackgroundImage(
        UIImage(),
        for: .any,
        barMetrics: .default)
    UINavigationBar.appearance().shadowImage = UIImage()
}

Just put this function at the first Viewcontroller and call it in viewdidload

回答20:

In iOS8, if you set the UINavigationBar.barStyle to .Black you can set the bar's background as plain color without the border.

In Swift:

UINavigationBar.appearance().translucent = false
UINavigationBar.appearance().barStyle = UIBarStyle.Black
UINavigationBar.appearance().barTintColor = UIColor.redColor()

回答21:

Here's a very simple solution:

self.navigationController.navigationBar.clipsToBounds = YES;

回答22:

The problem with setting a background image is it removes blurring. You can remove it without setting a background image. See my answer here.

回答23:

You should add a view to a bottom of the UISearchBar

let rect = searchController.searchBar.frame;
let lineView : UIView = UIView.init(frame: CGRect.init(x: 0, y: rect.size.height-1, width: rect.size.width, height: 1))
lineView.backgroundColor = UIColor.init(hexString: "8CC73E")
searchController.searchBar.addSubview(lineView)

回答24:

Simple solution – Swift 5

Create an extension:

extension UIImage {

    class func hideNavBarLine(color: UIColor) -> UIImage? {

        let rect = CGRect(x: 0, y: 0, width: 1, height: 1)
        UIGraphicsBeginImageContext(rect.size)
        let context = UIGraphicsGetCurrentContext()
        context?.setFillColor(color.cgColor)
        context?.fill(rect)


        let navBarLine = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return navBarLine
    }
}

Add this to viewDidLoad():

self.navigationController?.navigationBar.shadowImage = UIImage.hideNavBarLine(color: UIColor.clear)

回答25:

I know this is an old thread, but I found a solution that works really well:

Subclass UINavigationBar. In your UINavigationBar subclass, override didAddSubview with the following code:

- (void)didAddSubview:(UIView *)subview
{
    [super didAddSubview:subview];

    if ([subview isKindOfClass:[UIImageView class]]) {
        [subview setClipsToBounds:YES];
    }
}

回答26:

I Just created an extension for this... Sorry about formatting (this is my first answer).

Usage:

  override func viewDidLoad() {
    super.viewDidLoad()
    self.navigationController?.hideShadow = true
}

Extension:

 UINavigationController.swift
//  Created by Ricardo López Rey on 16/7/15.

import Foundation


struct UINavigationControllerExtension {
    static var hideShadowKey : String = "HideShadow"
static let backColor = UIColor(red: 247/255, green: 247/255, blue: 248/255, alpha: 1.0)
}

extension UINavigationController {

    var hideShadow : Bool {
        get {
            if let ret =  objc_getAssociatedObject(self, &UINavigationControllerExtension.hideShadowKey) as? Bool {
                return ret
            } else {
                return false
            }


        }
        set {
            objc_setAssociatedObject(self,&UINavigationControllerExtension.hideShadowKey,newValue, objc_AssociationPolicy(OBJC_ASSOCIATION_RETAIN_NONATOMIC))

            if newValue {


            self.navigationBar.setBackgroundImage(solidImage(UINavigationControllerExtension.backColor), forBarMetrics: UIBarMetrics.Default)

                self.navigationBar.shadowImage = solidImage(UIColor.clearColor())
            } else {
                self.navigationBar.setBackgroundImage(nil, forBarMetrics: UIBarMetrics.Default)
            }
        }
    }

    private func solidImage(color: UIColor, size: CGSize = CGSize(width: 1,height: 1)) -> UIImage {
        var rect = CGRectMake(0, 0, size.width, size.height)
        UIGraphicsBeginImageContextWithOptions(size, false, 0)
        color.setFill()
        UIRectFill(rect)
        var image: UIImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }


}

回答27:

Within AppDelegate, this has globally changed the format of the NavBar:

 func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    UINavigationBar.appearance().setBackgroundImage(UIImage(), forBarPosition: UIBarPosition.Any, barMetrics: UIBarMetrics.Default)
    UINavigationBar.appearance().shadowImage = UIImage()
    UINavigationBar.appearance().tintColor = UIColor.whiteColor()
    UINavigationBar.appearance().barTintColor = UIColor.redColor()
    UINavigationBar.appearance().translucent = false
    UINavigationBar.appearance().clipsToBounds = false
    UINavigationBar.appearance().backgroundColor = UIColor.redColor()
    UINavigationBar.appearance().titleTextAttributes = [NSFontAttributeName : (UIFont(name: "FONT NAME", size: 18))!, NSForegroundColorAttributeName: UIColor.whiteColor()] }

Haven't managed to implement anything different on a specific VC, but this will help 90% of people

回答28:

For iOS 9 users, this worked for me. just add this:

UINavigationBar.appearance().shadowImage = UIImage()

回答29:

-(void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    UIImage *emptyImage = [UIImage new];
    self.navigationController.navigationBar.shadowImage = emptyImage;
    [self.navigationController.navigationBar setBackgroundImage:emptyImage forBarMetrics:UIBarMetricsDefault];
}

回答30:

Objective C Answer to Above Question

// removing 1px line of navigation bar

[[UINavigationBar appearance] setBackgroundImage:[[UIImage alloc]init] forBarMetrics:UIBarMetricsDefault];
[[UINavigationBar appearance] setShadowImage:[[UIImage alloc] init]];
[[UINavigationBar appearance] setTranslucent:NO];
[[UINavigationBar appearance] setTintColor:[UIColor yourColor]];

来源：https://stackoverflow.com/questions/19226965/how-to-hide-uinavigationbar-1px-bottom-line

标签

ios

objective-c

swift

ipad

uinavigationbar

How to hide UINavigationBar 1px bottom line

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