如何在 UITabBarItem 中添加小红点

Question

如何在UITabBarItem 的右上角添加红点。

我已经搜索了一段时间，有些人说这可以设置UITabBarItem的徽章值。但是当我尝试将徽章值设置为空白空间“”时，红点有点大。如何我能买到合适的吗？非常感谢。

Answer 1

为您想要的UITabBarItem 设置badgeValue，如下所示：

    // for first tab
    (tabBarController!.tabBar.items!.first! as! UITabBarItem).badgeValue = "1"

    //for second tab
    (tabBarController!.tabBar.items![1] as! UITabBarItem).badgeValue = "2"

    // for last tab
    (tabBarController!.tabBar.items!.last! as! UITabBarItem).badgeValue = "final"

对于来自UITabBarItem 的remove 和badge，只需分配nil

(tabBarController!.tabBar.items!.first! as! UITabBarItem).badgeValue = nil

你可以得到输出 Like

更多信息请参考link

选择--2

    var lbl : UILabel = UILabel(frame: CGRectMake(225, 5, 20, 20))
    lbl.layer.borderColor = UIColor.whiteColor().CGColor
    lbl.layer.borderWidth = 2
    lbl.layer.cornerRadius = lbl.bounds.size.height/2
    lbl.textAlignment = NSTextAlignment.Center
    lbl.layer.masksToBounds = true
    lbl.font = UIFont(name: hereaddyourFontName, size: 13)
    lbl.textColor = UIColor.whiteColor()
    lbl.backgroundColor = UIColor.redColor()
    lbl.text = "1"  //if you no need remove this

    // add subview to tabBarController?.tabBar
    self.tabBarController?.tabBar.addSubview(lbl)

输出是

Answer 2

你可以试试这个方法：

func addRedDotAtTabBarItemIndex(index: Int) {

    for subview in tabBarController!.tabBar.subviews {

        if let subview = subview as? UIView {

            if subview.tag == 1314 {
                subview.removeFromSuperview()
                break
            }
        }
    }
    let RedDotRadius: CGFloat = 5
    let RedDotDiameter = RedDotRadius * 2

    let TopMargin:CGFloat = 5

    let TabBarItemCount = CGFloat(self.tabBarController!.tabBar.items!.count)

    let HalfItemWidth = CGRectGetWidth(view.bounds) / (TabBarItemCount * 2)

    let  xOffset = HalfItemWidth * CGFloat(index * 2 + 1)

    let imageHalfWidth: CGFloat = (self.tabBarController!.tabBar.items![index] as! UITabBarItem).selectedImage.size.width / 2

    let redDot = UIView(frame: CGRect(x: xOffset + imageHalfWidth, y: TopMargin, width: RedDotDiameter, height: RedDotDiameter))

    redDot.tag = 1314
    redDot.backgroundColor = UIColor.redColor()
    redDot.layer.cornerRadius = RedDotRadius


    self.tabBarController?.tabBar.addSubview(redDot)
}

Answer 3

我想出了一个破解解决方案。

func addRedDotAtTabBarItemIndex(index: Int,dotRadius: CGFloat) {

    var tabBarButtons = [UIView]()

    // find the UITabBarButton instance.
    for subview in tabBarController!.tabBar.subviews.reverse() {

        if subview.isKindOfClass(NSClassFromString("UITabBarButton")) {

            tabBarButtons.append(subview as! UIView)
        }
    }

    if index >= tabBarButtons.count {
        println("out of bounds")
        return
    }

    let tabBar = tabBarButtons[index]

    var selectedImageWidth: CGFloat!
    var topMargin: CGFloat!

    for subview in tabBar.subviews {

        if subview.isKindOfClass(NSClassFromString("UITabBarSwappableImageView")) {

            selectedImageWidth = (subview as! UIView).frame.size.width
            topMargin = (subview as! UIView).frame.origin.y
        }
    }

    // remove existing red dot.
    for subview in tabBar.subviews {

        if subview.tag == 999 {
            subview.removeFromSuperview()
        }
    }

    let redDot = UIView(frame: CGRect(x: CGRectGetMidX(tabBar.bounds) + selectedImageWidth / 2 + dotRadius, y: topMargin, width: dotRadius * 2, height: dotRadius * 2))

    redDot.backgroundColor = UIColor.redColor()
    redDot.layer.cornerRadius = dotRadius   // half of the view's height.
    redDot.tag = 999

    tabBar.addSubview(redDot)

}

Answer 4

我测试这个问题的答案。但不适用于 iPad。 现在我发现，当你在iPhone上添加这个时，tabBarItem左右边距为2，每个项目边距为4。代码如下：

    NSInteger barItemCount = self.tabBar.items.count;

    UITabBarItem *barItem = (UITabBarItem *)self.tabBar.items[index];
    CGFloat imageHalfWidth = barItem.image.size.width / 2.0;

    CGFloat barItemWidth = (BXS_WINDOW_WIDTH - barItemCount * 4) / barItemCount;
    CGFloat barItemMargin = 4;
    CGFloat redDotXOffset = barItemMargin / 2 + barItemMargin * index + barItemWidth * (index + 0.5);

和 iPad 如下：

    barItemWidth = 76;
    barItemMargin = 34;
    redDotXOffset = (BXS_WINDOW_WIDTH - 76 * barItemCount - 34 * (barItemCount - 1)) / 2.0 + 76 * (index + 0.5) + 34 * index;

希望这是有用的。

Answer 5

适用于 iPad 和 iPhone。 能够自动隐藏和计算索引。

如果 self 不是 UITabBarController，则调用 self.setTabBarDotVisible(visible:true)。

如果 self 是 UITabBarController，则调用 self.setTabBarDotVisible(visible:true, index:2)。

import UIKit

public extension UIViewController {

func setTabBarDotVisible(visible:Bool,index: Int? = nil) {

    let tabBarController:UITabBarController!

    if self is UITabBarController
    {
        tabBarController = self as! UITabBarController
    }
    else
    {
        if self.tabBarController == nil
        {
            return
        }
        tabBarController = self.tabBarController!
    }

    let indexFinal:Int

    if (index != nil)
    {
        indexFinal = index!
    }
    else
    {
        let index3 = tabBarController.viewControllers?.index(of: self)

        if index3 == nil
        {
            return;
        }
        else
        {
             indexFinal = index3!
        }

    }

    guard let barItems = tabBarController.tabBar.items else
    {
        return
    }

    //


    let tag = 8888

    var tabBarItemView:UIView?

    for subview in tabBarController.tabBar.subviews {

        let className = String(describing: type(of: subview))

        guard className == "UITabBarButton" else {
            continue
        }

        var label:UILabel?
        var dotView:UIView?

        for subview2 in subview.subviews {

            if subview2.tag == tag {
                dotView = subview2;
            }
            else if (subview2 is UILabel)
            {
                label = subview2 as? UILabel
            }

        }


        if label?.text == barItems[indexFinal].title
        {
            dotView?.removeFromSuperview()
            tabBarItemView = subview;
            break;
        }
    }

    if (tabBarItemView == nil || !visible)
    {
        return
    }



    let barItemWidth = tabBarItemView!.bounds.width

    let x = barItemWidth * 0.5 + (barItems[indexFinal].selectedImage?.size.width ?? barItemWidth) / 2
    let y:CGFloat = 5
    let size:CGFloat = 10;

    let redDot = UIView(frame: CGRect(x: x, y: y, width: size, height: size))

    redDot.tag = tag
    redDot.backgroundColor = UIColor.red
    redDot.layer.cornerRadius = size/2


    tabBarItemView!.addSubview(redDot)
}

}

Answer 6

这是 Swift 4 解决方案：

1) 将 BaseTabBar 自定义类添加到您的项目中：

import UIKit

class BaseTabBar: UITabBar {
  static var dotColor: UIColor = UIColor.red
  static var dotSize: CGFloat = 4
  static var dotPositionX: CGFloat = 0.8
  static var dotPositionY: CGFloat = 0.2

  var dotMap = [Int: Bool]()

  func resetDots() {
    dotMap.removeAll()
  }

  func addDot(tabIndex: Int) {
    dotMap[tabIndex] = true
  }

  func removeDot(tabIndex: Int) {
    dotMap[tabIndex] = false
  }

  override func draw(_ rect: CGRect) {
    super.draw(rect)
    if let items = items {
      for i in 0..<items.count {
        let item = items[i]
        if let view = item.value(forKey: "view") as? UIView, let dotBoolean = dotMap[i], dotBoolean == true {
          let x = view.frame.origin.x + view.frame.width * BaseTabBar.dotPositionX
          let y = view.frame.origin.y + view.frame.height * BaseTabBar.dotPositionY
          let dotPath = UIBezierPath(ovalIn: CGRect(x: x, y: y, width: BaseTabBar.dotSize, height: BaseTabBar.dotSize))
          BaseTabBar.dotColor.setFill()
          dotPath.fill()
        }
      }
    }
  }

}

2) 将 UITabBarController 中的 UITabBar 自定义类更改为 BaseTabBar。

3）管理可以访问tabBarController的地方的点

func updateNotificationCount(count: Int) {
    if let tabBar = navigationController?.tabBarController?.tabBar as? BaseTabBar {
      if count > 0 {
        tabBar.addDot(tabIndex: 0)
      } else {
        tabBar.removeDot(tabIndex: 0)
      }
      tabBar.setNeedsDisplay()
    }
  }

Answer 7

我添加了 5 个标签栏索引，并根据通知发生添加点。首先，创建 Dots 视图数组。

var Dots = [UIView](repeating: UIView(), count: 5)

func addRedDotAtTabBarItemIndex(index: Int) {

    if  self.Dots[index].tag != index {

        let RedDotRadius: CGFloat = 7
        let RedDotDiameter = RedDotRadius

        let TopMargin:CGFloat = 2

        let tabSize = self.tabBarController.view.frame.width / CGFloat(5)

        let  xPosition = tabSize * CGFloat(index - 1)

        let tabHalfWidth: CGFloat = tabSize / 2

        self.Dots[index] =  UIView(frame: CGRect(x: xPosition + tabHalfWidth - 2 , y: TopMargin, width: RedDotDiameter, height: RedDotDiameter))

        self.Dots[index].tag = index
        self.Dots[index].backgroundColor = UIColor.red
        self.Dots[index].layer.cornerRadius = RedDotRadius

        self.tabBarController.tabBar.addSubview(self.Dots[index])

    }
}

如果要从选定索引中删除点，请使用以下代码：

func removeRedDotAtTabBarItemIndex(index: Int) {

        self.Dots[index].removeFromSuperview()
        self.Dots[index].tag = 0
    }

Answer 8

如果你想避免遍历子视图和潜在的危险黑客攻击，我所做的就是将徽章的背景颜色设置为清除并使用带样式的项目符号点显示为徽章：

tabBarItem.badgeValue = "●"
tabBarItem.badgeColor = .clear
tabBarItem.setBadgeTextAttributes([NSAttributedStringKey.foregroundColor.rawValue: UIColor.red], for: .normal)

这似乎比其他答案更具前瞻性。

Answer 9

简单的解决方案 在情节提要 tabbaritem 徽章值中设置空间。

如果我们在输出下方添加空格，您可以获得：

Answer 10

这在当前的iOS 版本中非常简单

tabBarItem.badgeValue = " "

它显示tabbar item顶部的红点

Answer 11

在 Swift 5 中：

tabBarItem.badgeValue = "1"

改变默认颜色使用：

tabBarItem.badgeColor = UIColor.systemBlue

Answer 12

斯威夫特 5+

这进入属于该选项卡的控制器

替代。你只需要抓住正确的tabBarItem

func updateTabBarBadge(showDot: Bool) {
    
    guard let tbi = tabBarItem else {
        return
    }
    
    if showDot {
        tbi.setBadgeTextAttributes([.font: UIFont.systemFont(ofSize: 6), .foregroundColor:UIColor(named: "Primary")!], for: .normal)
        tbi.badgeValue = "⬤"
        tbi.badgeColor = UIColor.clear
    } else {
        tbi.badgeValue = nil
    }
    
}