ios - 如何在 swift 4 中将角标(Badge)放在 UIBarButtonItem 上？

Question

我想在 UIBarButtonItem 上放置角标(Badge)。为此，我使用以下引用

Add badge alert in right bar button item in swift

在此，我创建了“UIBarButtonItem+Badge.swift”文件并将该代码放入其中。在我的 View Controller 中，我使用了 UIBarButtonItem 的导出。并调用该函数，但它对我不起作用。我的 View Controller 文件是这个

我的 UIBarButtonItem+Badge.swift 文件是

extension CAShapeLayer {
func drawRoundedRect(rect: CGRect, andColor color: UIColor, filled: Bool) {
    fillColor = filled ? color.cgColor : UIColor.white.cgColor
    strokeColor = color.cgColor
    path = UIBezierPath(roundedRect: rect, cornerRadius: 7).cgPath
   }
  }

   private var handle: UInt8 = 0;

   extension UIBarButtonItem {
private var badgeLayer: CAShapeLayer? {
    if let b: AnyObject = objc_getAssociatedObject(self, &handle) as AnyObject? {
        return b as? CAShapeLayer
    } else {
        return nil
    }
}

func setBadge(text: String?, withOffsetFromTopRight offset: CGPoint = CGPoint.zero, andColor color:UIColor = UIColor.red, andFilled filled: Bool = true, andFontSize fontSize: CGFloat = 11)
{
    badgeLayer?.removeFromSuperlayer()

    if (text == nil || text == "") {
        return
    }

    addBadge(text: text!, withOffset: offset, andColor: color, andFilled: filled)
}

 func addBadge(text: String, withOffset offset: CGPoint = CGPoint.zero, andColor color: UIColor = UIColor.red, andFilled filled: Bool = true, andFontSize fontSize: CGFloat = 11)
{
    guard let view = self.value(forKey: "view") as? UIView else { return }

    var font = UIFont.systemFont(ofSize: fontSize)

    if #available(iOS 9.0, *) { font = UIFont.monospacedDigitSystemFont(ofSize: fontSize, weight: UIFont.Weight.regular) }
    let badgeSize = text.size(withAttributes: [NSAttributedString.Key.font: font])

    // Initialize Badge
    let badge = CAShapeLayer()

    let height = badgeSize.height;
    var width = badgeSize.width + 2 /* padding */

    //make sure we have at least a circle
    if (width < height) {
        width = height
    }

    //x position is offset from right-hand side
    let x = view.frame.width - width + offset.x

    let badgeFrame = CGRect(origin: CGPoint(x: x, y: offset.y), size: CGSize(width: width, height: height))

    badge.drawRoundedRect(rect: badgeFrame, andColor: color, filled: filled)
    view.layer.addSublayer(badge)

    // Initialiaze Badge's label
    let label = CATextLayer()
    label.string = text
    label.alignmentMode = CATextLayerAlignmentMode.center
    label.font = font
    label.fontSize = font.pointSize

    label.frame = badgeFrame
    label.foregroundColor = filled ? UIColor.white.cgColor : color.cgColor
    label.backgroundColor = UIColor.clear.cgColor
    label.contentsScale = UIScreen.main.scale
    badge.addSublayer(label)

    // Save Badge as UIBarButtonItem property
    objc_setAssociatedObject(self, &handle, badge, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}

private func removeBadge() {
    badgeLayer?.removeFromSuperlayer()
   }
  }

我的viewcontroller文件是这个

import UIKit

@IBOutlet weak var notificationLabel: UIBarButtonItem!

查看didload函数

notificationLabel.addBadge(text: "4")

Answer 1

这是@VishalPethani 的 swift 4 解决方案，有一些方便的小改动。

将此 UIBarButtonItem 添加到您的代码中:

class BadgedButtonItem: UIBarButtonItem {

    public func setBadge(with value: Int) {
        self.badgeValue = value
    }

    private var badgeValue: Int? {
        didSet {
            if let value = badgeValue,
                value > 0 {
                lblBadge.isHidden = false
                lblBadge.text = "\(value)"
            } else {
                lblBadge.isHidden = true
            }
        }
    }

    var tapAction: (() -> Void)?

    private let filterBtn = UIButton()
    private let lblBadge = UILabel()

    override init() {
        super.init()
        setup()
    }

    init(with image: UIImage?) {
        super.init()
        setup(image: image)
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setup()
    }

    private func setup(image: UIImage? = nil) {

        self.filterBtn.frame = CGRect(x: 0, y: 0, width: 30, height: 30)
        self.filterBtn.adjustsImageWhenHighlighted = false
        self.filterBtn.setImage(image, for: .normal)
        self.filterBtn.addTarget(self, action: #selector(buttonPressed), for: .touchUpInside)

        self.lblBadge.frame = CGRect(x: 20, y: 0, width: 15, height: 15)
        self.lblBadge.backgroundColor = .red
        self.lblBadge.clipsToBounds = true
        self.lblBadge.layer.cornerRadius = 7
        self.lblBadge.textColor = UIColor.white
        self.lblBadge.font = UIFont.systemFont(ofSize: 10)
        self.lblBadge.textAlignment = .center
        self.lblBadge.isHidden = true
        self.lblBadge.minimumScaleFactor = 0.1
        self.lblBadge.adjustsFontSizeToFitWidth = true
        self.filterBtn.addSubview(lblBadge)
        self.customView = filterBtn
    }

    @objc func buttonPressed() {
        if let action = tapAction {
            action()
        }
    }

}

然后你就可以像这样使用它了:

class ViewController: UIViewController {

    let btn = BadgedButtonItem(with: UIImage(named: "your_image"))

    override func viewDidLoad() {
        super.viewDidLoad()

        self.navigationItem.rightBarButtonItem = btn

        btn.tapAction = {
            self.btn.setBadge(with: 1)
        }

    }
}

这是一个带有一些自定义的存储库 https://github.com/Syngmaster/BadgedBarButtonItem