更改导航栏底部边框颜色Swift

Question

它适用于

import UIKit

class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    self.navigationController?.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: .Default)
    self.navigationController?.navigationBar.shadowImage = UIColor.redColor().as1ptImage()


}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

extension UIColor {
    func as1ptImage() -> UIImage {
        UIGraphicsBeginImageContext(CGSizeMake(1, 1))
        let ctx = UIGraphicsGetCurrentContext()
        self.setFill()
        CGContextFillRect(ctx, CGRect(x: 0, y: 0, width: 1, height: 1))
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
}

但是当我添加一个UITableView它没有出现在它上面时,当我添加一个UISearchView它出现但删除导航栏.

谁知道如何解决这个问题？

Answer 1

您必须调整shadowImage导航栏的属性.

试试这个吧.我在UIColor上创建了一个类别作为帮助,但您可以按照自己喜欢的方式进行重构.

extension UIColor {
    func as1ptImage() -> UIImage {
        UIGraphicsBeginImageContext(CGSizeMake(1, 1))
        let ctx = UIGraphicsGetCurrentContext()
        self.setFill()
        CGContextFillRect(ctx, CGRect(x: 0, y: 0, width: 1, height: 1))
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
}

选项1:在单个导航栏上

然后在你的视图控制器中(将UIColor更改为你喜欢的):

// We can use a 1px image with the color we want for the shadow image
self.navigationController?.navigationBar.shadowImage = UIColor.redColor().as1ptImage()

// We need to replace the navigation bar's background image as well 
// in order to make the shadowImage appear. We use the same 1px color tecnique
self.navigationController?.navigationBar.setBackgroundImage(UIColor.yellowColor??().as1ptImage(), forBarMetrics: .Default)    

选项2:在所有导航栏上使用外观代理

不是在每个导航栏上设置背景图像和阴影图像,而是可以依赖UIAppearance代理.您可以尝试将这些行添加到AppDelegate,而不是在viewDidLoad中添加先前的行.

// We can use a 1px image with the color we want for the shadow image
UINavigationBar.appearance().shadowImage = UIColor.redColor().as1ptImage()

// We need to replace the navigation bar's background image as well 
// in order to make the shadowImage appear. We use the same 1px color technique
UINavigationBar.appearance().setBackgroundImage(UIColor.yellowColor().as1ptImage(), forBarMetrics: .Default)

Answer 2

@TheoF,@ Alessandro和@Pavel的精彩贡献.

这是我为...所做的

斯威夫特4

extension UIColor {

    /// Converts this `UIColor` instance to a 1x1 `UIImage` instance and returns it.
    ///
    /// - Returns: `self` as a 1x1 `UIImage`.
    func as1ptImage() -> UIImage {
        UIGraphicsBeginImageContext(CGSize(width: 1, height: 1))
        setFill()
        UIGraphicsGetCurrentContext()?.fill(CGRect(x: 0, y: 0, width: 1, height: 1))
        let image = UIGraphicsGetImageFromCurrentImageContext() ?? UIImage()
        UIGraphicsEndImageContext()
        return image
    }
}

使用它viewDidLoad():

/* In this example, I have a ViewController embedded in a NavigationController in IB. */

// Remove the background color.
navigationController?.navigationBar.setBackgroundImage(UIColor.clear.as1ptImage(), for: .default)

// Set the shadow color.
navigationController?.navigationBar.shadowImage = UIColor.gray.as1ptImage()

Answer 3

Swift 4.0 - 5.2 的解决方案

这是用于更改底部导航栏线的高度和颜色的小扩展

extension UINavigationController
{
    func addCustomBottomLine(color:UIColor,height:Double)
    {
        //Hiding Default Line and Shadow
        navigationBar.setValue(true, forKey: "hidesShadow")
    
        //Creating New line
        let lineView = UIView(frame: CGRect(x: 0, y: 0, width:0, height: height))
        lineView.backgroundColor = color
        navigationBar.addSubview(lineView)
    
        lineView.translatesAutoresizingMaskIntoConstraints = false
        lineView.widthAnchor.constraint(equalTo: navigationBar.widthAnchor).isActive = true
        lineView.heightAnchor.constraint(equalToConstant: CGFloat(height)).isActive = true
        lineView.centerXAnchor.constraint(equalTo: navigationBar.centerXAnchor).isActive = true
        lineView.topAnchor.constraint(equalTo: navigationBar.bottomAnchor).isActive = true
    }
}

添加此扩展后，您可以在任何 UINavigationController 上调用此方法（例如从 ViewController viewDidLoad()）

self.navigationController?.addCustomBottomLine(color: UIColor.black, height: 20)