Question

我只想更改其中一个标签项目的背景颜色。我找到了许多链接，但没有得到任何帮助。

要求：

而且，这是我设置标签栏项目的方式

 let myTabBarItem3 = (self.tabBar.items?[2])! as UITabBarItem
 myTabBarItem3.image = UIImage(named: "ic_center")?.withRenderingMode(UIImageRenderingMode.alwaysOriginal)
 myTabBarItem3.selectedImage = UIImage(named: "ic_center")?.withRenderingMode(UIImageRenderingMode.alwaysOriginal)

我想要的是中心标签栏项目的黑色背景。

有什么想法吗？

是的，它不是重复的，因为之前的回答不准确，添加额外的子视图从来都不是一个好选择，所以期待朋友们提供一些好的解决方案

Answer 1

您可以将子视图添加到父tabBar 然后，您可以在子视图上设置背景颜色。计算tabBarItem的偏移量和宽度，并在其下插入subView。

let itemIndex = 2
let bgColor = UIColor(red: 0, green: 0, blue: 0, alpha: 1.0)

let itemWidth = tabBar.frame.width / CGFloat(tabBar.items!.count)
let bgView = UIView(frame: CGRectMake(itemWidth * itemIndex, 0, itemWidth, tabBar.frame.height))
bgView.backgroundColor = bgColor
tabBar.insertSubview(bgView, atIndex: 0)

Answer 2

您可以使用imageView来实现这种效果，尝试这种方法

let myImageView: UIImageView = {
    let imageView = UIImageView()
    return imageView
}()

// Now add this imageView as subview and apply constraints
tabbar.addSubview(myImageView)
myImageView.translatesAutoresizingMaskIntoConstraints = false        
addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:[v0(28)]", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": myImageView]))
addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[v0(28)]", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": myImageView]))

tabbar.myImageView.image = UIImage(named: "ic_center")?.withRenderingMode(UIImageRenderingMode.alwaysTemplate)
tabbar.myImageView.tintColor = UIColor.black

Answer 3

如果您想更改仅tabBarItem中心的背景颜色，可以按照以下代码进行操作。

注意：以下所有代码都在自定义类中使用，该类将UITabBarController扩展为：

class tabbarVCViewController: UITabBarController, UITabBarControllerDelegate {

    // MARK: - ViewController Override Methods.
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.

        setupInitilView()
    }

    // MARK: - setup Initial View Methode.
    private func setupInitilView() {

        delegate = self

        // Sets the default color of the icon of the selected UITabBarItem and Title
        UITabBar.appearance().tintColor = UIColor.white

        // Sets the default color of the background of the UITabBar
        UITabBar.appearance().barTintColor = UIColor.white

        // Sets the background color of the selected UITabBarItem (using and plain colored UIImage with the width = 1/5 of the tabBar (if you have 5 items) and the height of the tabBar)
        //UITabBar.appearance().selectionIndicatorImage = UIImage().makeImageWithColorAndSize(color: UIColor.black, size: CGSize.init(width: tabBar.frame.width/4, height:  tabBar.frame.height))


        // Uses the original colors for your images, so they aren't not rendered as grey automatically.
        for item in self.tabBar.items! {
            if let image = item.image {

                //item.image = image.withRenderingMode(.alwaysTemplate)

                item.image = image.withRenderingMode(.alwaysOriginal) //Use default image colour as grey colour and your centre image default colour as white colour as your requirement.
            }
        }

         //Change the backgound colour of specific tabBarItem.

         let itemIndex:CGFloat = 2.0

         let bgColor = UIColor.black
         let itemWidth = tabBar.frame.width / CGFloat(tabBar.items!.count)
         let bgView = UIView(frame: CGRect.init(x: itemWidth * itemIndex, y: 0, width: itemWidth, height: tabBar.frame.height))
        bgView.backgroundColor = bgColor
        tabBar.insertSubview(bgView, at: 0)

    }

    // MARK: - UITabbarController Override Methods .
    override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {

    }


    // MARK: - UITabBarControllerDelegate Methods
    func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {

        return true
    }
}

根据您的用户界面将tabBarItem图片默认颜色设置为灰色，并在资产中将tabBarItem图片默认颜色设置为白色。

并且你想要扩展UIImage类来制作你需要的大小的纯色图像：

extension UIImage {
    func makeImageWithColorAndSize(color: UIColor, size: CGSize) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(size, false, 0)
        color.setFill()
        UIRectFill(CGRect.init(x: 0, y: 0, width: size.width, height: size.height))
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image!
    }
}

Answer 4

试试这个：

 UITabBar.appearance().tintColor = UIColor.pink
 UITabBar.appearance().barTintColor = UIColor.white
            if #available(iOS 10.0, *) {
                UITabBar.appearance().unselectedItemTintColor = UIColor.white
            } else {
                // Fallback on earlier versions
            }
let x = Double(UIScreen.main.bounds.width / 5.0)
let y = Double(tabBarController!.tabBar.frame.size.height)
let indicatorBackground: UIImage? = self.image(from: UIColor.black, for: CGSize(width: x, height: y))
UITabBar.appearance().selectionIndicatorImage = indicatorBackground

帮助方法

func image(from color: UIColor, for size: CGSize) -> UIImage {
    let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
    autoreleasepool {
        UIGraphicsBeginImageContext(rect.size)
    }
    let context: CGContext? = UIGraphicsGetCurrentContext()
    context?.setFillColor(color.cgColor)
    context?.fill(rect)
    let image: UIImage? = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image!
}

在Swift中更改UITabBarItem的背景颜色

4 个答案: